I never used ph controller and never had air stone in my planted tank. now im setting up a new 100G tank with aquasoil and soft water (gh 3, kh3 )and installed PH controller. before any co2 injection the PH is 6.3-6.4 (reading from the ph controller) i set the controller to shut off the co2 at 5.8 (i know that by the kh/ph table its a lot - but i dont trust it). i would like to add air stone as i would like to introduce a few species of shrimps and heard they need good amounts of oxygen .
Now my question is that : if i add air stone to the tank during dark hours - will it give more oxygen to the water? i think its like driving a car with one leg on the brakes and one leg on the gas... but still want your opinion?
Will it make the controller work harder to achieve the desire PH (and co2 levels)? i dont mind loosing CO2 for nothing but would like to keep my shrimps alive!

I've got 9 shrimp in my 29 gallon tank. I don't consider that they need more O2 than fish, what they do need is good water conditions.

I run my CO2 24/7. I allow the output from my small ecco filter and the small powerhead at the other side of the tank to ripple the surface. I like the current of water within the tank and consider this beneficial to all the flora and fauna within. I achieve an estimated 25 to 30 ppm of CO2 on one bubble per 1.5 seconds. I don't consider that I am losing a serious quantity of CO2.

I can't help you on the controller but if I was setting one up I would have it turn the CO2 off during the dark period rather than have it conrolled by the Ph.

Ian

I've just re-read your post and I think that your Ph calibration must be off because I don't think you can achieve anything like 45ppm CO2 without injection, which is what your figures are suggesting. I would also add a little bicarb to up your Kh a little to give a margin of safety, aim for about 5 degrees.

Ian

Ian, the Amano substrate influences the kh/ph chart, so I wouldn't pay any attention to it.

OIC Jerime. Just googled on it and if it has that effect on water stats I'm not sure that I would want it in my tank, Amano name and all.

Ian

This is what I do with my DIY co2. I have it all set up on timers. When lights go out, reactor powerhead turns off, effectively shutting co2 off (it just bubbles out of tank) and at same time airstone comes on to add oxygen for night. In morning airstone turns off a couple hours before lights come on. Powerhead rector comes on at same time giving co2 a couple hours to build back up to 30 ppm for when lights come on. You could do same thing only you would have timer for whole co2 setup where mine is just for reactor.

Good luck, Bill

PS
Airstone could probably wait a few hours after lights to turn on because there is plenty of oxygen from photosynthesis/pearling.

An airstone will reduce the O2 by turning it on at night as the water has been oversaturated(beyond 100%) with dissolved O2 from the plants all day.

Why remove it?

Wait till the light have been off for several hours, maybe 6 or more.

Depends on your plant growth rate and density, but I routinely have 140-150% when the lights go off.

In the morning, I have 90-110%.

Regards,
Tom Barr

Tom,
What about dealing with "excess CO2"(if there really is such a thing). I have found that the only practical way to assure constant 30ppm DIY CO2 during the light cycle is to overshoot sometimes to as high as 54 or more ppm. Having read all the warnings about high CO2, over 40ppm, and having experienced gasping fish (before tank was heavily planted) I installed airtstone on timer to drop CO2 at night, which it does very effectively.

Is high CO2 a problem at all if there is plenty of oxygen? If a highly planted tank has 90 to 110% oxygen saturation in the morning does it need the airstone at all?

Bill