[TreeofSouls]

Thx to anyone who can give me some insight. I have a 36 gal bow tank, 1 betta, 5 Danio and 5 Tetra. Biomaster 350 with a Fluval 3.0 LED. I'm having trouble with the correct application of pressurized CO2. I have an American Marine PH controller that is reading my tank at a steady 6.4 PH. My water out of the tap is much closer to 7. MY KH seems to be around 4. I have a large piece of driftwood in the tank which may be lowering it. The problem is, the PH is so low that the controller won't inject any CO2. I'm nervous about lowering the threshold much past 6.3 for the health of the fish. I have the controller plugged into a timer that turns it off at night as I don't want to inject at night. I thought there would be a much greater PH swing at night, and that the controller would have turned on this morning, but there didn't seem to be much of a PH rise overnight and I'm a bit confused as to why. Any idea's?

 

[Basementfishtanks]

That’s a good question. Do you have a high plant load? Are you trying to raise your ph at all? Closer to 7?

 

[TreeofSouls]

I recently replanted that tank. Micro sword carpet, Monte Carlo on driftwood and a bunch of fast growing stem plants.

 

[Immortal1]

Thx to anyone who can give me some insight. I have a 36 gal bow tank, 1 betta, 5 Danio and 5 Tetra. Biomaster 350 with a Fluval 3.0 LED. I'm having trouble with the correct application of pressurized CO2. I have an American Marine PH controller that is reading my tank at a steady 6.4 PH. My water out of the tap is much closer to 7. MY KH seems to be around 4. I have a large piece of driftwood in the tank which may be lowering it. The problem is, the PH is so low that the controller won't inject any CO2. I'm nervous about lowering the threshold much past 6.3 for the health of the fish. I have the controller plugged into a timer that turns it off at night as I don't want to inject at night. I thought there would be a much greater PH swing at night, and that the controller would have turned on this morning, but there didn't seem to be much of a PH rise overnight and I'm a bit confused as to why. Any idea's?

Generally speaking, many of us running tanks full of stem plants and fish will have atleast a 1.0 to 1.3 drop in pH on our tanks.
With that said, I would start by saying you first need to know what the degassed pH of your tap water is. Easiest way would be to leave a cup of tap water standing out for a couple of days. The fastest way would be to leave a cup of tap water standing out with an air stone running in it for maybe 6-12 hours.
You said your tap water is about 7. And you have 4dKH. Sounds similar to numbers I used to have. My guess is your degassed pH may end up being about 7.4.
If that is true, then the 6.4pH you have your controller set to is pretty good. 6.3pH cutoff should not be a big issue either. Typically for me, the best approach is first to understand how your Betta acts normally - i.e. swims round in the middle of the tank, rarely goes to the surface except for food.
If you notice your pH is now at 6.3 and the Betta is now spending a lot of time near the surface, away from your CO2 source - then it's time to note that pH level and raise it up 1/10th (i.e. 6.4=ok, 6.3=stressed. Stay with 6.4).

I should also add that air stones can be very useful in a CO2 tank. You say the American Marine is on a timer... Add an additional timer for an air stone. Have the air stone run when the CO2 is not running. This will help add additional O2 to your water column which will also make your fish happier. FYI - the air stone itself does not add oxygen to the water. The bubbles from the air stone breaks up the water surface which allows Gaseous Exchange to happen. "Light Reading"

 

[TreeofSouls]

Thx Immortal. I have a Twinstar Nano plus that is supposed to be delivering O2 into the system periodically. Maybe I'll change that to an airstone.

 

[BOTIA]

Thx to anyone who can give me some insight. I have a 36 gal bow tank, 1 betta, 5 Danio and 5 Tetra. Biomaster 350 with a Fluval 3.0 LED. I'm having trouble with the correct application of pressurized CO2. I have an American Marine PH controller that is reading my tank at a steady 6.4 PH. My water out of the tap is much closer to 7. MY KH seems to be around 4. I have a large piece of driftwood in the tank which may be lowering it. The problem is, the PH is so low that the controller won't inject any CO2. I'm nervous about lowering the threshold much past 6.3 for the health of the fish. I have the controller plugged into a timer that turns it off at night as I don't want to inject at night. I thought there would be a much greater PH swing at night, and that the controller would have turned on this morning, but there didn't seem to be much of a PH rise overnight and I'm a bit confused as to why. Any idea's?

Without gas exchange , ph won't drop or rise much.
kh 4 water will have a natural degassed ph of 8.2

Your tapwater will undoubtedly increase in pH after 24 hours due to offgassing of chlorine.

A cup of water leave it out for 24 hours and test the pH. This will give you your off gassed PH starting point.

I think you're fine.

However make sure your probe is properly calibrated and that your large piece of driftwood isn't adding a lot of tannic acid artificially keeping your pH down. I once had this happen after I drilled several large holes through a large piece of mopani wood to serve as a loach " hotel" .

I should've boiled it first as it turned out I had a large tannic acid swing. That stopped my CO2 from coming on and Created an algae outbreak because the CO2 would not come on.

I should've boiled the wood after I drilled all the holes through it to leech out the tannins and nitrates.
It was very confusing until I figured it out.