Baking Soda to Raise PH

[manny]

Has anyone tried baking soda to raise their ph? If so, did it work?

[dan]

is there any side efects useing this mix? i've always bought the buffer, but if it works i might give it a try

[matt]

For normal buffering, baking soda works fine. It's sodium bicarbonate, and alkalinity basically refers to the level of carbonate ions in the water. So, the bicarbonate dissolves to carbonate ions. This does not usually raise ph much; I don't really understand the reaction. Washing soda, which is sodium carbonate, does the same thing, but raises ph in the process.

[manny]

Well, here's what I'm trying to do.

My KH measures at 10.4
Calcium is at 375
and my ph is at 7.9

I'm trying to get my Calcium and ph up a little. So what I'm gonna do is use a ph buffer (which I forgot I had) to try and bring my ph up. Then slowly raise my calcium by using Kent Turbo Calcium after I get the ph right. Then just keep it there using B-Ionic. As of right now I'm just using the B-Ionic and its keeping my calcium and alkalinity steady but hasn't seemed to bring my calcium up much. Is my plan the right thing to do? Would I be doing it in the right order?

[Instar]

Manny, If your pH is too low for you with a Kh of 10.4 (assuming the test kits are accurate) then you have another issue. I would raise the calcium a little and forget the pH right now. The Kh already indicates that the pH should be buffered enough. If you drive it higher trying to raise the pH, then you will really be out of balance with the calcium even worse than you are. Normal sea water kH is 7.5 with calcium a little less than 400. First I would raise the calcium SLOWLY and watch for the kH to start coming down. When you are closer to balanced, check the Magnesium. Then decide where to go from there. Baking soda or washing soda is not what it needs right now (providing those tests are accurate that you listed). A normal tank can be expected to have an early a.m. pH of 7.9. Also check the pH after the 11 hours photoperiod with all the lights running to see what the swing during the day/night is.

[manny]

oh ok, i'll check my ph after my lights go out. that's probly why it measured so low cause it was in the morning when i tested it.

[GaryP]

Baking Soda will actually drop your pH. Washing Soda will raise it. What you want to do is use a 6:1 ratio of baking soda to washing soda as a buffer. The others are correct in that baking soda will raise alkalinity, but it will not raise pH. Since your pH is low, but alkalinity is high, I think you have an excess of bicarbonate, and low carbonate.

Larry is right, you have some other issues here. The third factor in the buffering issue is carbonic acid from CO2. If your pH is low, you probably have depleted most of your carbonate neutralizing carbonic acid. CO2 is produced at night when the lights are off and this results in pH being low.

Gary

[matt]

Yeah, I thought you might have a build up of CO2, but are you running your skimmer? If so, it's unlikely you have a gas exchange problem. 7.9 in the morning is not really a problem in itself, and unless you're using a decent ph probe, calibrated, you don't really know what your ph is. As long as your dkh is that high, I wouldn't worry about it. Toss a little calcium chloride in there every day, maybe it's best to do that late in the afternoon, and get your calcium up to 400 or so; that might take 3 or 4 days. I don't think it needs to be much higher. That will probably drop your dkh a little as well.

Gary;

I have understood that bicarbonate ions disassociate into carbonate ions in seawater. How could he have an excess of bicarbonate? Maybe there's something about this I'm not getting; that's likely.