- Thread Starter
If I place the outflow correctly it would not produce a buildup inside as it would be to the front edge. The inner cave is also with multiple access points both top, sides and front as you can see. I estimate about a 1 gallon to 1.5 g space under/inside and thus with the top opening most C02 would escape if trapped inside of the cave. The Chihiros Doctor unit also widly helps with better O2. I ran an experiment with a 5bps Co2 during the evening all night and no fish gasping or hurt. Without the CD I would not attempt this experiment or make sure you got a good diffused air input. Since having the CD unit I run no airstones at all for this tank.