So you've got your CO2 system all set up, whether it's DIY yeast powered, or pressurized, and you've even got your CO2 diffusing method set up and working great. But something's wrong. Your plants aren't growing faster, the algae is still there, and your pH isn't dropping. You check and double check your equipment and make sure there are no leaks anywhere and that CO2 is flowing fine. Chances are, all that CO2 you're pumping into your aquarium is being vented off into the atmosphere. What's the culprit? Here are the most common causes:
- Hang-on-back (HOB) Filters - There's a reason these filters aren't used often with high tech planted aquariums. All that water agitation involved with sucking it up and then churning it through filter media and dumping it back into the tank is sure to vent most if not all of your CO2. Try a canister or internal filter instead.
- Airstones - There should be no reason to have an airstone in your planted tank. The plants take care of providing any oxygen needed for fish. Using one with a high tech planted tank is sure to lower your CO2 levels. Unless this is intended (i.e. as an emergency measure when CO2 gets too high), take out the airstone! This also goes for all air pump powered figurines, etc. But if you're reading this blog you probably threw those out years ago anyway. If you haven't yet, please do, before you give Takashi Amano a heart attack!
- Powerhead/filter outlets - If you place powerheads or filter outlets too close to the surface of the water, they'll create turbulence which will vent CO2. Place all spraybars, filter outlets, and powerhead outlets a safe distance under the surface so you don't see too many ripples (if any at all).