Fluctuating pH

[Celestialgirl]

Over a week long period, my pH gradually rises from 7.4 to 8.2. My GH takes about 18-19 drops, my KH takes 6-7 drops. My tap water left out for 24 hours is 7.4. Any ideas on why my pH keeps changing? I'm concerned about whatever fish I add. I'm also cycled.

 

[V227]

It's far more common for ph to crash than rise. Did you use limestone in aquascaping your tank? Or have any crushed coral / dolomite in your filter material. All of these can cause your ph to rise. If your ph stabilizes at 8 -8.2 it probably won 't hurt your fish. The key word here is "stable". Fish don't react well to unstable conditions. I'm sure other AA members will provide additional information. Good luck.

 

[Celestialgirl]

I originally had just plain blue gravel but I've switched to black sand (Carib Sea brand). I added driftwood about a month ago. No limestone or crushed coral. The tank has been running over 5 months and has been fluctuating the whole time.

The problem is that it isn't stable. As soon as I change 25-30% of the water, it drops back to 7.4. If I do twice weekly water changes I can keep it stable at 7.4 but it's not truly stable.

Thanks for your response.

 

[V227]

You might try adding a small peice of malaysian drift wood. It's heavy and dense and will probably drop the ph some. The only drawback is that it will stain your water like weak tea.
Looks like you are handling the situation well. I've never had the type of aquarium sand you have so I have no idea if that's the cause.

 

[Celestialgirl]

It's Tahitian Moon Sand and it says it doesn't affect pH. Plus, when I had plain old gravel the same thing was happening.

I do have mopani drift wood in the tank already, do you know if it affects the water differently than the malaysian drift wood? I thought the mopani was supposed to drop the pH but it hasn't really made a difference either.

I think I have a tough case. I've spent a tremendous amount of time researching my issue and for most people it's due to soft water or tap water, which isn't my case.

 

[TMaier]

I'm gonna go out on a limb here. One of the other members said something to me once. Is it possible your source water is loaded with CO2 and the ph is low. But as it off gasses you ph rises?

 

[Celestialgirl]

I did put some water in a cup and let it gas off for 24 hours, do you think that's not enough time? Right out of the tap my pH is 7.4 and 24 hours later it was still 7.4. Is there a way to test for CO2?

 

[V227]

To test for co2, test your (ph) And the carbonate hardness (kh). Cross reference the results on
A chart readily available on line. I've never tried this, just looked it up.

 

[TMaier]

I did put some water in a cup and let it gas off for 24 hours, do you think that's not enough time? Right out of the tap my pH is 7.4 and 24 hours later it was still 7.4. Is there a way to test for CO2?

Their comment to me if I recall correctly was that letting water sit out it can increase the Co2?

But once it is in the tank with plants consuming and water surface agitation it is lost.

 

[Celestialgirl]

Well, according to that chart my CO2 is actually low... So I'm not sure what that means?

 

[TMaier]

The mystery continues. I'm as stumped as you. If it's any consolation the Planted guru's who pump Co2 speak of a drop in Ph by a full point when they have it running. And the fish handle it daily. Unless they go too far and there isn't enough oxygen lol.

Are your fish showing any signs of distress?

 

[Celestialgirl]

No, but I'm trying to figure it stocking. I have 5 platys and 5 sterbai Corys. I would love to get into some dwarf cichlids, maybe pearl gouramis. I just know I can't have sensitive fish while my pH is moving so much.

 

[TMaier]

If you had coral/aragonite it would probably stabilize it on the higher end.

Or add woods to bring it down. Or peat in the filter.

 

[Celestialgirl]

So I should switch to a substrates that raises pH to try to stabilize it?

I already have 1 piece of driftwood on the tank. I had two for a while but the tannins were a bit stronger than I'd like. No real effect on the pH occurred. The remaining piece has been there for a month or so.

 

[TMaier]

Substrate change is a big change. I suspect if you add just a bit of the coral/aragonite it will stabilize the ph.

 

[V227]

If you didn't like driftwood due to water staining, then you really wouldn't like peat.
The high end stableizing idea sounds good. Changing the substrate option leaves you with crushed coral or dolomite, both white. It would look more like an african cichlid tank. The water in my area is hard and the ph is similar to yours. Over the years I have kept German blue rams, Bolivians, even discus, with no problems. With rams, especially the germans, a clean tank is probably more important than your higher than average ph. Since you want rams but don't particularly like driftwood, consider buying a Texas Holey rock. The limestone will buffer your water and provide hiding places. Companies sell them on line "expensive" or visit your local rock yard or landscaping company "cheap - huge selection". I currently keep numerous varieties of new world cichlids "alleged soft water only fish" in my limestone aquascaped tanks. Keep AA updated, and don't stress too much over this.

 

[Mebbid]

What is your source of water?
What additives are you using?
What pH test kit?