You can get an Ista disposable system at most Petco's for about $50. Replacement CO2 cartridges are $10 each. The system is very cute.
In a 2.5l tank (do you really mean 2.5 liters or gallons?) it would last a while if you can get the bubble rate dialed in slow enough... however with no fauna there's not really any harm in running it higher, other than you'd use more CO2. I have a hard time adjusting the one I have with really low bubble rates.. it's really difficult to get the bubble rate slower than about 1 per second, but it's easier to adjust my Aquatek mini's down pretty low (I have one running just 12 bubbles a minute).
Yeah those are the ones I was looking at before making this thread. I didn't know Petco stocks them. That's a huge money saver! There's a Petco 5 minutes from me. The one I saw was on some site for $80 with bubble counter, diffuser, regulator, the cartridge and stand. Does the Petco one include all of this?
It's just flora for now. Fauna will will come in much much later after the tank has had time to stabilize. No clue what is going in there yet. Going to DSM the HC in the tank and leave it outside for now.
I really mean 2.5 liters not gallons. This is the whole reason why I decided to go with a disposable CO2 cartridge setup instead of a paintball or a real setup. A disposable CO2 cartridge setup will last quite some time on a 2.5 liter tank and take up minimal real estate in the tank and desk it's going on.