pH returns to 8.4+ whatever I do.

desx2501

New member
Hi,
I monitor my pH with an Apex Controller, and it's been giving "high" ratings for a while now. I've tested the pH with a regular test kit and the pH IS effectively high.

I'm using tap water that I treat for my top off and water changes so I tested the treated tap water and it reads about 8.0. I tried adding vinegar a few times already. The pH goes down (after 3-4mins since I add it in my sump, just "after" the probe") but I'd say about... 4-6h after, the pH is back to it's high value. The pH increases/decreases at day/night, but that's normal and it's not what worries me.

Here are some information that might be related to this :
It's a 40g tank with a 10g sump. It has 2×24w T5 HO iirc. There is a "day light" light over the sump that lights at night. There is a red algae (not talking about the slime, I'm talking about a "normal saltwater plant") and an hammerhead coral in the display tank, and a Chaeto in the sump.

The tank only has 2 clowns, 2 cardinals, an urchin and a small cleaning crew.

Any idea what I could/should do about that pH?
 
8.4 ph?

8.4 ph?

If the high PH isn't causing any problems I wouldn't worry about it. Their are other products out there that can lower PH.:twitch:
 
Adjusting pH with vinegar is usually a kind of bad idea. The effect is temporary at best, and you are adding organic carbon to the tank, fueling bacterial blooms if not careful.

I wouldn't worry about that pH too much. Especially if everything is happy.
 
The only "problem" with the pH I've seen yet is that the clown fish is slowly turning part black. It's not a black clown (sorry for the non-scientific names :-P ) but it's slowly becoming black, and I've been told it's caused by water being too basic. Last thing, is that I've been told that a pH this high might hurt the fish, even though the coral would still be fine.
 
How high are you talking about? I don't think fish are going to have trouble at 8.4

What are you dosing alk with? There might be some changes you could make there that would slowly lead to lower pH.
 
pH probes as they age and get dirty read high. If you haven't cleaned and calibrated in the last 30days that the first place to start. When I clean/calibrate mine it can go down .2 from that alone. If your not dosing kalkwasser or other additives that are know to be high in pH, then I highly suspect your readings are not accurate. It takes quite a bit of doing to consistantly read 8.4+.
 
I think pH 8.4 is perfect, and I wouldn't lower it. I agree that there's no good way to reduce the pH with an additive. What's the highest pH measured so far?
 
@disc1: 8.45 is the highest I've seen. I'm not dosing alk.

@David Grigor: The probes were calibrated 2months ago, and I confirmed the probe reading with a chemical test. I'm not dosing anything for the moment.

@bertoni: Highest was 8.45.

Since it seems not troublesome, I'll just monitor the pH and won't try to fix it, since by the look of it, it's not broken!

Thanks everyone for your input :-)
 
The ph sounds fine to me. The algae and nightime lighted fuge will lower CO2 and elevate ph particularly if the sytem is covered or otherwise limits gas exchange with the surrounding air.
 
More aeration should help limit the pH rise. Oily films on water surfaces might be an issue, for example. I agree that anything below 8.6 is fine.
 
More aeration should help limit the pH rise. Oily films on water surfaces might be an issue, for example. I agree that anything below 8.6 is fine.

Shouldn't aerating it only make the pH rise until the water is saturated(so not past healthy levels) and then it will have no additional affect? I have never heard of aeration keeping pH from rising.

Oxygen saturated water will prevent pH swings from day and night(like he is having) and keep the tank's pH more constant.
 
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