I have a 100 gallon tank and my pH monitor reads 7.5. In the morning before the CO2 kicks on it reads 8.0.

How do I lower this more?

I use a wet/dry but I have removed the drip plate, bio balls, etc... so it is basically just a sump now. I have my CO2 injected directly into my return pump so I get a good mist all over the tank.

The only problem I can think of is that it is outgassing in my sump. Tonight I will put a piece of PVC on the return to have it below the water line to cut down on surface/water agitation.

Any comments would be greatly appreciated.

Keith

George Booth, Steve Dixon and myself all reported independently back in the late/mid 1990's that the main issue was the overflow.

Gas loss should be the same otherwise if the sump/dry section of the wet/dry is sealed.

Often they have vents to add air into these sections.
Tape those up.

Bacteria on the biomedia produces CO2 and uses O2.
Sio the in/out result => no net gain or lost of CO2 really and if anything, a sealed dry section would give you a bit more CO2..........

Same with a canister.

But the overflow should have the level raised up to about 2" below the surface, not 6-12-18 inches etc.

This will also reduce noise and evaporation.
So add the media back, tape up any leaks etc in the wet/dry section, feed the CO2 reactor output into the suction side of the return pump.

Be careful after adding these changes, watch the fish so you do not gas them.

Regards,
Tom Barr

As another suggestion, how about submerging the exit of the drain line and planting the sump? If you prefer more stable CO2 ppm, put the main and the sump on opposite photoperiods. This sounds difficult to dose but in reality is easy with EI. FWIW I ditched my DIY wet/dry a long time ago and just use this method with plants as biofilters. Works well for me.

If the tank is drilled, Durso standpipe is the shiznit -- quiet, low surface agitation, allows high flow with minimal-no CO2 loss -- www.dursostandpipes.com

Hope this helps.

The duros are nice, you can DIY as well.

Planted filters do a wonder and can be used on any tank, not just planted tanks.

See some older APD post I had on types of plants and lighting for it.


Regards,
Tom Barr