Low Ph. Acceptable dKH and Ca

[Ruskin]

So I've had low PH since tank setup around February. I'm usually around 7.7 using a calibrated new Ph probe and confirmed with a Salifert test kit. Freshly mixed salt comes in around 8.4 for me.

Lately my Ph is dropping to about 7.60 to 7.55. My dKH is 8.9 and Ca is around 450 using Salifert test kits. I started Kalk via ATO on Saturday and its maintaining my numbers with only a 1/2 tsp per gallon. The Ph hasn't changed much.

I did the aeration test and its definelty a co2 issue as I got a Ph reading of 8.5 after an hour outside and testing inside gave me the same numbers as my tank. I have the windows open now to help get it back to better levels but this isnt going to be feasable everyday. I do not run a skimmer, and have an ATS instead.

So do I do the baked baking soda method to raise Ph? If so is there detailed instructions i could go over to make sure i do it safely. Or do I raise my kalk a bit since I have some room to go up with dKH and Ca?

Sorry for the long post, wanted to put as much info as I could think of.

[bertoni]

Kalk is more effective than baked baking soda (sodium carbonate) in raising pH, so there's not much more you can do chemically. How high is the pH reading with the windows open? Sometimes, tanks do better with more aeration. Getting good surface agitation can help remove surface films, which sometimes cause this problem.

[Ruskin]

In roughly 2 hours it's gone up by about 0.06.

Thanks for the info on Kalk, I didn't know that. My demand is low now anyways, so perhaps in time the amount will need to go up and it will bring my Ph to a more comfortable number. I may add more kalk just to see where I land with my next ato fill up.

I'll also try to adjust the powerheads for more surface agitation.

[bertoni]

Okay, let's see how much the powerheads help. It's not all that common, but sometimes they do solve the problem.

[hhaase]

So when you did the CO2 test outside you got a ph of 8.5, and when you tested inside it was 7.5? Sounds like a lot of atmospheric CO2 in your home that is getting getting absorbed by the water. Not uncommon for smaller homes or places that have gas stoves/ovens/water heaters.

-Hans

[Ruskin]

Hans, yeah that's what I was thinking too. The house is not small and is open concept but the tank is in the basement and its spray foamed down there so it's sealed up pretty well. It is on the other side of the house from the mechanical room.

I started looking into Co2 monitors today out of curiosity. The windows were open during the day today for around 10-12 hours and it jumped from 7.60 to 7.82. I shut everything after that for fear it might be too much of a jump? I did adjust the powerheads and add another 1/2 tsp of Kalk to a new bucket of ATO water as you suggested Jonathan, so maybe it's all playing a part?

[bertoni]

It's hard to know which changes are doing the most, but opening the windows often has a very large effect. I wouldn't worry about aeration causing a problem by shifting the pH. I'd be much more cautious about dosing a lot of lime. That will change other parameters, too.

[hhaase]

CO2 settles, so the concentrations will be higher in the basement. Maybe just circulation inside the house will be enough, but hard to tell without numbers to back anything up.

-Hans

[Ruskin]

Yea, I've left the Kalk at my normal. I think the powerheads and most importantly the fresh air are helping. Im at about 7.9 most days now which is a huge improvement over what its been.

I'll keep an eye on it over the next few weeks and if i cant get it to break 8+ I'll look into a monitor to see whats going on. Maybe theres a faulty appliance contributing more than it should somewhere.

[bertoni]

7.9 isn't that bad for a tank in a house. Lots of Tanks of the Month ran around 7.8.

[RobbyG]

Originally Posted by hhaase

CO2 settles, so the concentrations will be higher in the basement. Maybe just circulation inside the house will be enough, but hard to tell without numbers to back anything up.

-Hans

I was thinking the same thing.
If I was the OP I would plump a 3/4" PVC pipe from closest point outside the house down to the basement and cap the pipe with a nipple that the skimmer airline can attach to.

With my current setup all of my skimmer air is coming from outside the house.

[bertoni]

Fresher air through a skimmer sometimes helps. In many cases, though, aeration through the tank surface dominates, and the skimmer effect is negligible. If it's easy to try, though, I'd give it a shot.