55 gal planted CO2 question

Off-the-shelf systems like the Nutrafin probably aren't sufficient for a 55g. You could use Flourish Excel (liquid carbon) but that could get expensive over the long run.

Rex Grigg has a great discussion of pressurized CO2 at his site; the whole site is well-worth your time. :idea:

Yes- they should have a tank exchange program. They will likely want a deposit = the cost of the tank.

Minimum Equipment:
Regulator- dual guage is preferred but single gauge can be used.
Needle valve- to regulate flow rate.
Bubble Counter- to be able tp see flow when changing it by being able to count the bubbles/minute.
Co2 resistant tubining- to connect all the parts.
Teflon tape- to insure all threaded connections don't leak.

You will need a method for dispersing the co2 into the water. this can be as simple as running it though a canister or using a reactor of some sort.

Optional Equipment:
Reactor/diffusor- to get the max co2 into the water.
Solenoid- turns co2 on and off at a preset time or in response to pH level.
pH controller- used with a solenoid to measure pH and then have solenoid turn the co2 on or off.