It's possible, but it would get expensive. If you really need a CO2
system that large, consider going to a pressurized system. The buy-in cost is higher, but the upkeep is a lot cheaper and neater and the results are better. I've done both DIY CO2
and pressurized CO2
and the pressurized system wins hands down, even thought I've only been running it for a week.
If you watch craigslist and eBay and have a little luck, you can do a pressurized system for a decent price. I've got $35 into mine (soon to be $70 with a hydrotest and a refill), but I should be able to run for years with my one tank or run all my tanks for a year or so.