Cost of running your own Compressor

[Mattleycrue76]

I'm curious

I know quite a few of you have their own compressor/fill station setup and I've heard conflicting things about the cost of maintaining one. Do you have them to save money? Or more for convenience? How much does it typtically cost for filters and other consumables? The majority of people with fill stations that I know of dive quite a bit of trimix which leads me to believe that that's where the savings come into play. But at what point? Do any of you run a sort of "Co-Op" for lack of a better word with your close dive buddies and if so how has that worked out for you? Sorry for all the questions, I'm not trying to pry into anyone's business, I'm just genuinely curious about the costs and motivation for having your own setup.

[Sounder]

FWIW, I forget the numbers but when I looked into this I ended up buying more tanks. I believe you do it for convenience and to save on fuel driving to/from the fill station. I also remember it depending on exactly how much you're already paying for fills as to whether it's "worth it" or not.

It reminds me of a quote from Ben Villao: "I went out looking at new drysuits today, and came home with a large tube of Aquaseal."

[spatman]

pensacolaracer started this thread last spring that might answer some of your questions:

http://www.nwdiveclub.com/viewtopic.php?f=1&t=7594

[loanwolf]

It depends on how often you dive and what you dive. If you are diving a mix even nitrox and dive quite a bit it pays.

It can also pay in less maintenance costs and longer life of your tanks. As your air will more than likely be much cleaner than the shops.

One thing we do not think about in this country is how much does it cost you a mile to drive a vehicle down the road. My truck is about $1.25 a mile to move down the road in total costs. So if you figure that in and the dive shop is out of the way it all adds up. If you have to drive to the shop it is no longer a $12 nitrox fill but maybe a $50 fill with a 20+ mile round trip to the shop.

[camerone]

I think the old "if you gotta ask..." answer applies. Seriously not a cheap proposition. In fact, it's definitely a losing proposition. You also gain a new hobby - compressor maintenance and upkeep, as they are not plug-n-play items to keep around. You have to change oil (engine and compressor block), change filters, rebuild valves, maintain hoses, repack media, monitor air, blah blah blah.

I do it for convenience, not for cost savings. The nearest place to me that pumps 'mix is NWSD, and they're a PITA to get to in traffic since I live in Bellevue and I work in the I-district downtown. Plus, I work 60-ish hours a week, every week, so dropping and picking up tanks is a week in between...and don't ask about doing dives two days in a row. Matt's shop is awesome, but it's not anywhere convenient for me to use regularly. I had a Baby Booster for a few years, but I'd run out of "banked" mix or never have the right stuff to top off, and inevitably, I'd want to be diving the next morning, early. It sucks to have to rush away from the dive site to make it to a shop before they close, just so you can fill up.

If any of the LDSes here were like Amigo's in Ft. White, Florida, I probably wouldn't bother with it...24/7 fills with prior arrangement and you always fill your own. Most awesome dive shop ever, and Wayne absolutely rocks... I digress, though... I needed to build out a small station to do that.

The cheapest part of the whole thing is the compressor itself, for a small setup. The rest of the needed bits cost more.

I run a very small Coltri block (MCH-6, 3.5 cfm), with a petrol engine (Honda, 6.5 hp). New, I think they're $3500-ish, used in the $1500-$2000 range, depending on condition. It's plenty fine for rebreather work, which is what I use it for, but woe were the neighbors the day I decided to vip and clean my dubs, my two AL80 stages, my AL40 stage, and all the small tanks. I ran through three tanks of gasoline filling. Electric motors are cheaper to operate, but they're not portable and they fill slower.

I bought the compressor used at a fairly good price, with a pseudo-hyperfilter and a spare T of oxygen (empty). If I were an OC diver, though, I wouldn't have bought less than a 6cfm setup as 3.5 cfm is too slow to do dubs.

Add on to that setup:
- two sets of filters - primary and hyperfilter. Primaries are 20 hour replacements and cost $40/each. I built a repackable filter on the lathe to drop that primary filter cost to $8/each if I pack my own. The big filter costs quite a bit to repack, too. Just a quart-sized bottle of hopcalite catalyst is around $100. Add on sieve, food-grade oil, activated carbon, mobile 1 (for the gas engine) and o-rings, and it's not cheap. The hyperfilter lasts up to a year at the volumes I pump, since I keep it under pressure.

- hyperfilter. Fortunately, I had one with the compressor. It needed some work on the lathe to really function as such, but it wasn't too bad to fix. These suckers cost a fortune to buy. Even if you go with a Rix oil-free compressor, you need a large dessicant stack to get rid of the moisture.

- bank bottles - Craigslist is your friend... I own my bottles, but new they're $300-ish. Craigslist will yield deals in the $50-$75 range for a T bottle I keep one of helium and one of o2 around. Helium refills are $140, Oxygen are $30, and that's for about 250 cf of gas. Up to you whether you have the setup to use all of it or not...

- booster pump - I have a booster to scrounge all that expensive helium and to give me full O2 top ups. That's $2000 with whips. If you find a used one, you can get them for $1000-$1500 and rebuild it yourself.

- Fittings - you need whips, whip ends, moisture and carbon monoxide monitor discs and holders, a "priority valve" to keep the filter under pressure at all times, gauges to monitor things, check valves, bleed valves, CGA540 and CGA580 fittings for the gas bottles, hoses, etc. They add up really fast when you're trying to put together a decent system.

I -don't- have bank bottles, I don't have autodrains on the compressor (but wish I did...there's another $750 - $1k...), and I don't continuous blend, even though I have a stick to do it with, since the compressor is only good to 40% nitrox, and I'm a believer that nitrox less than 50% is useless (just carry a damn O2 bottle under your arm and be done with it.)

If you want to continuous blend, I recommend adding a He analyzer - $800 and up - to the setup. I PP blend instead.

If you're doing a permanent install, SS tubing and Swagelok fittings don't come cheap. I keep my stuff portable to drag out to the coast or whatever. Plus, it's cheaper that way, and with a gas motor on the compressor block, I'm not doing that inside the garage

Finally -- and here's where most people forget about the home setup - you HAVE to test your air. I test right before every filter change... why? That's when the air should be at its absolute WORST, and I still had better be pumping OCA. What's the point of testing on a brand new filter? If you had everything set up right, of course you'll pass. Air tests are around $100/each. So, there's a minimum of $100/year in air testing fees...more if it's a heavy year.

In short, it's a pain in the ass to run a compressor set up. If I had the kind of job or lifestyle where I had time to routinely make it to an LDS while they were open without having to plan days and days ahead (or sacrifice a Saturday) I probably wouldn't bother. I don't, though, and I like the freedom of being able to fill what I want, when I want it.

If you want to save money diving Trimix - the answer isn't a compressor and fill station. The answer is to quit blowing bubbles and wasting the helium

[loanwolf]

I think the old "if you gotta ask..." answer applies. Seriously not a cheap proposition. In fact, it's definitely a losing proposition. You also gain a new hobby - compressor maintenance and upkeep, as they are not plug-n-play items to keep around. You have to change oil (engine and compressor block), change filters, rebuild valves, maintain hoses, repack media, monitor air, blah blah blah.

I do it for convenience, not for cost savings. The nearest place to me that pumps 'mix is NWSD, and they're a PITA to get to in traffic since I live in Bellevue and I work in the I-district downtown. Plus, I work 60-ish hours a week, every week, so dropping and picking up tanks is a week in between...and don't ask about doing dives two days in a row. Matt's shop is awesome, but it's not anywhere convenient for me to use regularly. I had a Baby Booster for a few years, but I'd run out of "banked" mix or never have the right stuff to top off, and inevitably, I'd want to be diving the next morning, early. It sucks to have to rush away from the dive site to make it to a shop before they close, just so you can fill up.

If any of the LDSes here were like Amigo's in Ft. White, Florida, I probably wouldn't bother with it...24/7 fills with prior arrangement and you always fill your own. Most awesome dive shop ever, and Wayne absolutely rocks... I digress, though... I needed to build out a small station to do that.

The cheapest part of the whole thing is the compressor itself, for a small setup. The rest of the needed bits cost more.

I run a very small Coltri block (MCH-6, 3.5 cfm), with a petrol engine (Honda, 6.5 hp). New, I think they're $3500-ish, used in the $1500-$2000 range, depending on condition. It's plenty fine for rebreather work, which is what I use it for, but woe were the neighbors the day I decided to vip and clean my dubs, my two AL80 stages, my AL40 stage, and all the small tanks. I ran through three tanks of gasoline filling. Electric motors are cheaper to operate, but they're not portable and they fill slower.

I bought the compressor used at a fairly good price, with a pseudo-hyperfilter and a spare T of oxygen (empty). If I were an OC diver, though, I wouldn't have bought less than a 6cfm setup as 3.5 cfm is too slow to do dubs.

Add on to that setup:
- two sets of filters - primary and hyperfilter. Primaries are 20 hour replacements and cost $40/each. I built a repackable filter on the lathe to drop that primary filter cost to $8/each if I pack my own. The big filter costs quite a bit to repack, too. Just a quart-sized bottle of hopcalite catalyst is around $100. Add on sieve, food-grade oil, activated carbon, mobile 1 (for the gas engine) and o-rings, and it's not cheap. The hyperfilter lasts up to a year at the volumes I pump, since I keep it under pressure.

- hyperfilter. Fortunately, I had one with the compressor. It needed some work on the lathe to really function as such, but it wasn't too bad to fix. These suckers cost a fortune to buy. Even if you go with a Rix oil-free compressor, you need a large dessicant stack to get rid of the moisture.

- bank bottles - Craigslist is your friend... I own my bottles, but new they're $300-ish. Craigslist will yield deals in the $50-$75 range for a T bottle I keep one of helium and one of o2 around. Helium refills are $140, Oxygen are $30, and that's for about 250 cf of gas. Up to you whether you have the setup to use all of it or not...

- booster pump - I have a booster to scrounge all that expensive helium and to give me full O2 top ups. That's $2000 with whips. If you find a used one, you can get them for $1000-$1500 and rebuild it yourself.

- Fittings - you need whips, whip ends, moisture and carbon monoxide monitor discs and holders, a "priority valve" to keep the filter under pressure at all times, gauges to monitor things, check valves, bleed valves, CGA540 and CGA580 fittings for the gas bottles, hoses, etc. They add up really fast when you're trying to put together a decent system.

I -don't- have bank bottles, I don't have autodrains on the compressor (but wish I did...there's another $750 - $1k...), and I don't continuous blend, even though I have a stick to do it with, since the compressor is only good to 40% nitrox, and I'm a believer that nitrox less than 50% is useless (just carry a damn O2 bottle under your arm and be done with it.)

If you want to continuous blend, I recommend adding a He analyzer - $800 and up - to the setup. I PP blend instead.

If you're doing a permanent install, SS tubing and Swagelok fittings don't come cheap. I keep my stuff portable to drag out to the coast or whatever. Plus, it's cheaper that way, and with a gas motor on the compressor block, I'm not doing that inside the garage

Finally -- and here's where most people forget about the home setup - you HAVE to test your air. I test right before every filter change... why? That's when the air should be at its absolute WORST, and I still had better be pumping OCA. What's the point of testing on a brand new filter? If you had everything set up right, of course you'll pass. Air tests are around $100/each. So, there's a minimum of $100/year in air testing fees...more if it's a heavy year.

In short, it's a pain in the ass to run a compressor set up. If I had the kind of job or lifestyle where I had time to routinely make it to an LDS while they were open without having to plan days and days ahead (or sacrifice a Saturday) I probably wouldn't bother. I don't, though, and I like the freedom of being able to fill what I want, when I want it.

If you want to save money diving Trimix - the answer isn't a compressor and fill station. The answer is to quit blowing bubbles and wasting the helium

Come on Cam you dont need to test .

No it all adds up. But if you dive a lot and are OC it makes since. If I am on OC DM'ing a tech class I will go though about $250.00 a day in nitrox and deco gas, If it is a TM class as much as $500.00 a day in gas if i were buying it at the typical LDS. Three sets of twins and three sets of deco bottles. Were making it myself is far cheaper and I can do it at night between classes. That's is also were my rebreather took me less than 2 months to pay for it in gas savings verses buying gas at a shop or keeping a OC fill/mixing station at the house.

[boydski]

I have to agree with Cameron, I don't think running your own compressor really saves you any money. It is hard to beat the convenience and ability to pump whatever you want when you want it.

I bought a used Rix Compressor about six years ago simply because it was becoming impossible for me to get Nitrox fills in a timely fashion. Little did I know at the time that I'd wind up with an Oxygen Booster and ten T-bottles of Helium, Argon and Oxygen!

I had a lot of help from friends and local dive shops that donated analyzers, helium bottles, etc., but if you add the cost of all the bits and pieces that make up a complete fill station, its a frightening amount of money.

As for the convenience, my favorite addition to my setup was running some SS tubing to the outside wall of my garage and attaching a 25' fill whip. This allows me to fill my doubles while they are still sitting in the boat (on the trailer). Not having to haul tanks into and out of the boat all of the time sure makes my life easy.

I think that my booster (which cost $6k) eventually paid for itself, but I consider the whole fill station more of a break-even kind of expenditure that is definitely worth the time and cost as it allows you to go diving more, which is the whole point.

YMMV,

[Mattleycrue76]

Scott that setup has me drooling. I'm a ways off from Trimix diving and it's becomming apparent that the cost savings for helitrox mixes probably isn't there but somehow the thought of being independant and being able to fill what I want when I want is intrigueing. I'm not in the market for a compressor(yet) but if I were to run across something what would I want to be looking for or avoid at all costs. I ask this because i may get a chance to buy a Bauer compressor for pretty cheap but I don't have any specs on it yet.

[camerone]

Scott that setup has me drooling. I'm a ways off from Trimix diving and it's becomming apparent that the cost savings for helitrox mixes probably isn't there but somehow the thought of being independant and being able to fill what I want when I want is intrigueing. I'm not in the market for a compressor(yet) but if I were to run across something what would I want to be looking for or avoid at all costs. I ask this because i may get a chance to buy a Bauer compressor for pretty cheap but I don't have any specs on it yet.

If you're seriously considering 'mix, you should seriously consider the CCR route instead. Depending on the unit, and the accessories, you break even in as little as 50-100 trimix dives based on cost of gas at retail. Annual service is expensive for the O2 cell replacements, but if you're regularly diving 'mix, it will pay for itself.

Bauers are excellent units - other than the pathetic small stock filter on the unit, the block is definitely a favorite out there. Easy rebuilds, good parts availability, and a nice three-stage unit.

I happen to like the Coltri MCH-6 block that I have. It's resold by Nuvair and Max-Aire both with their own sticker plastered over the Coltri one. They're all the same unit. The onboard filter is acceptable for Grade-E air, but you will change it a lot (but not as much as the Bauer's!) Some people don't like the fact it's a four-stage compressor, and that it runs the pistons fairly fast. OTOH, unlike the other small compressors out there, its manual claims you are perfectly fine using it to pump banked bottles... none of the other small ones think that's within the design parameters.

Rix units are great - less filtration, and they're oil free, so it's a lot easier to get OCA out of them. Parts are very expensive for them, and I've heard the special Rix grease you need costs a fortune. You can filter air from a small compressor just as effectively, so while the Rix is initially attractive for not needing anything other than dessicant, it's rather moot when you actually look into what it takes to get a small compressor pumping OCA. I'm not saying they're bad (they're not...good stuff), but the oil-free thing isn't necessarily as much of an advantage as the marketing brochures want you to believe.

Things to stay away from - Walter-Kidde, Stewart-Warner, or any of the old military surplus garbage. Some of it wasn't even intended for breathing air - I've seen flamethrower compressors being sold to divers! While they may run, parts are harder and harder to come by when they die or break down. These seem like a bargain, but they're anything but...

[boydski]

Rix units are great - less filtration, and they're oil free, so it's a lot easier to get OCA out of them. Parts are very expensive for them, and I've heard the special Rix grease you need costs a fortune....

Camerone is correct about the RIX units and the parts being very expensive. It is easy to get OCA from them, but the lack of lubrication means replacing the teflon packing on the high pressure piston fairly frequently. Fortunately, its an easy job.

The special Rix grease is only expensive if you buy it from Rix. I use Petron Plus ( $8 for a tube that will last 5-6 years).

[loanwolf]

Scott that setup has me drooling. I'm a ways off from Trimix diving and it's becomming apparent that the cost savings for helitrox mixes probably isn't there but somehow the thought of being independant and being able to fill what I want when I want is intrigueing. I'm not in the market for a compressor(yet) but if I were to run across something what would I want to be looking for or avoid at all costs. I ask this because i may get a chance to buy a Bauer compressor for pretty cheap but I don't have any specs on it yet.

Matt go CCR all you really need is a booster and a few HP tanks for air to mix with, a cheap shop compressor to run the booster, and a set of twins or a old K orT bottle that is only good for banking dill. By the time you buy everything else you will spend more on equipment than a CCR Rig and training. And then on top of that you the cost of gas it makes no sense to do OC anymore. Don't get me wrong I still like to dive OC once in a while but overall it makes no since today. You can do CCR right out of the gate. their is no reason to do OC tech if you are truly wanting to go the tech way. The overall cost, extended range, deco advantages, comfort in and out of the water, easy of travel is all hard to beat.

I got rid of the compressor and now just use the booster, If i am on the road i run it off standard scuba cylinders and do not need a compressor. I get 6-8 hrs of bottom time on 23cf of gas typically, 3 or 4 90-120min dives. I can typically fill 10 times off a set of twin 120's (actually get much more than that as the tanks are never empty all the way). That is 60-80 hrs of bottom time off one set of twin 120's of dill, verses one maybe 2 hrs on OC. A $40 240cf bottle of O2 will last even longer most of the time.

It is something to take a look at verses spending all the money on a compressor and associated equipment. If you have questions lets have a beer and talk .

[Mattleycrue76]

Thanks for all the responses, I am beginning to understand the complexity of running a complete fill station and I certainly buy the argument of CCR over OC for trimix costs. I have always (since I first heard of them) been interested in RB technology and actually don't doubt that I'll end up on one someday. However there are a few reasons why not right now in no particular order. First of all I am just finishing up my T1 cert through UTD. I own pretty much all the OC gear that will be necessary through at least T2. So from a hardware standpoint there is a big difference between buying the gas a few dives at a time and plopping down 10-12k for a CCR. Second, my dive buddies are all currently on OC, I am really enjoying the team based approach of UTD, and while I believe there will soon be alot of "mixed team" diving coming down the road I don't see a whole lot of it going on right now. Third, I hold the belief (and I could be wrong) that a good CCR diver should have some OC Deco diving experience first since a failure of your unit basically turns you into an OC diver in a split second. Having said all that if my diving at some point takes me into deep trimix territory I will definitely be looking long and hard at a rebreather.

So, why couldn't someone just buy a booster and some gas bottles (o2/HE/), then use a shopcompressor or tank to boost HE and O2 into the tanks and go by the LDS to get them topped with air (OCA)? Maybe there's some fatal flaw in this idea or maybe the savings aren't great enough I dunno. But it would still be considerably more convenient than driving the the shop twice for mix fills.

[vbcoachchris]

[Mattleycrue76]

There's a reason I chose to ask these questions here rather than TDS. I am not trying to start a fest.

[spatman]

So, why couldn't someone just buy a booster and some gas bottles (o2/HE/), then use a shopcompressor or tank to boost HE and O2 into the tanks and go by the LDS to get them topped with air (OCA)? Maybe there's some fatal flaw in this idea or maybe the savings aren't great enough I dunno. But it would still be considerably more convenient than driving the the shop twice for mix fills.

i've been a bit curious about standalone boosters as well, though i admit i do not understand them at all...

[loanwolf]

We used to to that all the time. Most of the shops will not let you do that anymore. They get pissed if they find out that is what you are up to. So we had to get our own compressors after they put a stop to it.

[loanwolf]

Thanks for all the responses, I am beginning to understand the complexity of running a complete fill station and I certainly buy the argument of CCR over OC for trimix costs. I have always (since I first heard of them) been interested in RB technology and actually don't doubt that I'll end up on one someday. However there are a few reasons why not right now in no particular order. First of all I am just finishing up my T1 cert through UTD. I own pretty much all the OC gear that will be necessary through at least T2. So from a hardware standpoint there is a big difference between buying the gas a few dives at a time and plopping down 10-12k for a CCR. Second, my dive buddies are all currently on OC, I am really enjoying the team based approach of UTD, and while I believe there will soon be alot of "mixed team" diving coming down the road I don't see a whole lot of it going on right now. Third, I hold the belief (and I could be wrong) that a good CCR diver should have some OC Deco diving experience first since a failure of your unit basically turns you into an OC diver in a split second. Having said all that if my diving at some point takes me into deep trimix territory I will definitely be looking long and hard at a rebreather.

So, why couldn't someone just buy a booster and some gas bottles (o2/HE/), then use a shopcompressor or tank to boost HE and O2 into the tanks and go by the LDS to get them topped with air (OCA)? Maybe there's some fatal flaw in this idea or maybe the savings aren't great enough I dunno. But it would still be considerably more convenient than driving the the shop twice for mix fills.

Matt you can get new units from $3500 and up now.

[camerone]

Second, my dive buddies are all currently on OC,

We'll find you some better buddies :biggrin: To each his own, and there's nothing wrong wasting our national helium supply as bubbles, if that's what you want to do. A lot of your O/C gear does get re-used, though, and prices on mCCR units are in the $5k range, with some units as low as $3500 or so.

So, why couldn't someone just buy a booster and some gas bottles (o2/HE/), then use a shopcompressor or tank to boost HE and O2 into the tanks and go by the LDS to get them topped with air (OCA)? Maybe there's some fatal flaw in this idea or maybe the savings aren't great enough I dunno. But it would still be considerably more convenient than driving the the shop twice for mix fills.

I did this for quite a while myself, before I had the compressor. I've had a Jetsam booster for three or four years now. If you can make it to the LDS and they're open when you want/need to go, it works fine. For the rebreather bottles, I kept an 80 of O2 and an 80 of 21/35 or 18/45 around all the time and transfilled via the booster. What got hard was the bailout bottles for the dive. As I would always use a little bit here and there, I would re-top 40s or 80s with air, dropping to leaner and leaner mixes.

I also ran a pneumatic booster off the dubs as drive gas ($5/fill...) There's plusses and minuses to an LP compressor vs dubs to run the booster...if you go the LP shop compressor route, you need an oil free compressor that can do 150 psi continuous - basically there's a Sears one and a DeWalt one that work (they're two-stage oil free, and "200 psi," which we all know is a joke...) They're kind of inexpensive, and if you value your booster, you do need to install a small dessicator inline with the output before the booster to dry the air. Otherwise, you will eventually trash your booster.

With any pneumatic booster, the lower the supply gas, the less efficient the booster works out to be, more so with helium than oxygen. I once drained an entire set of dubs filling a 19 cf bottle of trimix from my 80 cf bank bottle whilst really trying to scrounge...

In this case, it's a flexibility and convenience thing. I believe that a small booster is almost required kit for a rebreather diver...you can get away with probably 75-80% of your fill needs with only the booster and the right whips, if you have enough tanks and plan strategically as to what to bank at home. It's that other 25% that you can't do which used to get me.

It's a little harder for me as my girlfriend dives an SCR (hard to bank 42% without wasting bottles), and she occasionally dives O/C. So, for me the booster worked great, but for her needs, the compressor makes more sense. "Yah, honey, I got the compressor for _you._ It's all about you, dear..."

[boydski]

So, why couldn't someone just buy a booster and some gas bottles (o2/HE/), then use a shopcompressor or tank to boost HE and O2 into the tanks and go by the LDS to get them topped with air (OCA)?

I know several people that are currently doing the very thing you describe. It works well for them as their LDS is close by. At times it can be inconvenient when they are too late getting to the shop or home to get the gas they want, but extra tanks or buddies with compressors can usually solve that issue.

As Camerone describes, if you're a long way from OCA, it probably will become a hassle. If you can get access to a shop compressor (or Scott C's awesome garage) without the long distance travel, then starting with a booster may work out for you. I think the HI boosters are less then $3k now, but if you're topping off doubles, you'll want a booster big enough to handle the volume.

A couple of guys melted down their baby booster trying to fill too many sets of doubles. The little boosters work great for the rebreather guys, but are not so hot for filling many sets of twins.

Of course an electric booster is the cat's meow if you can afford it. No boost air, just push a button and they quietly fill your twins, deco tanks, etc.

[vbcoachchris]

I was kidding about the

I do this for several people already

Scott

[camerone]

A couple of guys melted down their baby booster trying to fill too many sets of doubles. The little boosters work great for the rebreather guys, but are not so hot for filling many sets of twins.

I've used it to top off 40's for deco, but it's really slow for that, and it's about the limit of what it's good for. It's meant as a rebreather tool, definitely. If you're going to boost for O/C, then you want something that's a little bigger. Also, get something double-acting where it'll pump on both sides of the stroke. The Baby Booster is very inefficient, but if you consider the design parameters, it's an excellent bit of kit. Brain dead simple inside, cheap (~$2k loaded with whips and fittings), very easy to rebuild/field strip with only a set of hex keys, etc.

It's design was for use on dive boats by rebreather guys...when the O/C guys came up with 500 psi left, you would go around, plug into their BC fitting, and scrounge their tanks down to the IP of the first stages to drive your booster and top off your oxygen to a full fill. For a permanent or high use scenario, it's not a great solution. It's also not isolated between drive and source gas, so if you don't use relatively clean gas to drive the pump, you WILL contaminate the side that pumps HP O2... and that's bad.

Of course an electric booster is the cat's meow if you can afford it. No boost air, just push a button and they quietly fill your twins, deco tanks, etc.

I am jealous of that Masterline. I can't justify it, but that doesn't mean I'd pass up the opportunity to own one.

I'm actually thinking of converting my Coltri from gas to electric. I think I can do it for $150, and I'll keep the gas engine for travel. It'll make winter fills a lot nicer, especially since I cleaned out the garage and turned the third bay into my little diveshop of horrors a couple of weekends ago. There's actually room to move around in there!