Varietys The Spice Of Life

[rhizome]

Costs .

Used tank will run about $50, new about $175. Solenoid valve and flow meter combo will run about $150. Fills on a 20# about $20.

Single orifice burner @ ~400, scaling up to ~1200 for a commercial unit. Can't imagine a PS garden needing more than one orifice . ( Pauses for giggles). What's an LP tank cost these days, like $30? I know I pay $6 to refill a grill tank.

You can control either system with-

-A cheap 15min interval timer ~15
-A decent digi timer ~20
-A cycle timer (analog) ~110
-Cycle timer (digital) ~150
-A ppm controller ~450 and up

Hazzards of each .

Well, w/ the tank the hazards are pretty much flooding the room w/ unregulated gas, and dropping the tank on yer foot/lap. I guess theoretically you could snap off the valve stem, but it's only 800psi, so it won't go off and do the rocket thing like an o2 tank.
Big danger is tank discharging accidentally, displacing air/02 in an enclosed space and causing suffocation. You'd need a very tight room, and to be leaking the volume of the room in co2 over a short period of time to do this, but it's possible. ( Guy I knew died this way w/ a tank of NO2.) If you don't sleep in yer room, I wouldn't worry about it.
And, obviously, all the compressed gas stuff- standard cautions.

W/ a burner, you have a lot of the same issues, plus the presence of an open flame in the grow. LP goes gaseous @ well below atmospheric pressure, has same leak factors, flammable gas, yada yada- but you usually catch leaks, because you can smell em. Modern burners have electronic ignition, so the pilot flame is no longer an issue. Installed by a competant person who has read and followed the installation instructions, and has a reasonable understanding of how to not catch shit on fire, and checks for complete combustion on a regular basis- I'd say the risk is about nil.
Again, you could drop the tank on your foot/lap.

Combustion CO2 has a co-generate of water vapor, and throws a little heat. Not a hazard, just a management issue. That, and the set-up cost, are why I'd rec a tank system for a small (6x6/under) room and a burner for a larger room.

Be aware that higher atmo co2 levels can cause pH drop, esp in a DWC rig- again, management.

Longevity of Co2 vs LP ?

Either way, delivery gear will last a lifetime, control gear less so. I don't remember the CO2 yeild ratio for LP, but I wanna say it's right around 50%, so 40# of propane will last about as long as 20# of gas. Check my math on that, though.

Dif controls and manufacturers .

See list above. Right now I think the Sentinal stuff is the best bang/buck in the market, but YMMV. I don't trust the CAP stuff for this application- I know of one ppm-1 that stuck on and cooked the paint off of a burner. Long time ago, but scary...

As much as it spooks me , A burner / LP might fit our situation a lil better . We're at Home Cheapo 5 days a week = easy to swap LP tanks . All the gearhead friends would ask questions at the welding supply store about all the Co2 tanks , and they're not open on the weekends either .

Well, there's your answer. Ya just grill three meals a day
Don't let it spook ya- yer not an idiot.

Rhizome / or anyone else for that matter - Whats your take on all the basic Systems , controllers avalible ? The 40% increase in yield claims I'm seeing are prob. hogwash like the savings claims of a didi-ballast I bet ? I've only seen 1 person here lately playin w/ Co2 .

You'll be freakin amazed what juicing a well tuned room can do. Think Nitrous- car's not running well, it won't go all that fast... Car's got a good mechanical tune and is running @ good effieciency already, and ya bleed in a little nitrous...yummy.

I've yet to see somebody introduce CO2 to a well tuned room and not have to tie the first run down off the lights. But if yer not already tuned, you get bupkus.

Think about how a dramatically increased growth rate is going to affect your process, and that should tell you if gas is something you want to play with.

It is possible to g(r)o(w) too fast.