High Ph in oscar aquarium

Hi, I have 1 oscar in a 125 gallon aquarium. I noticed the PH is quite high about a 8.3- 8.4. I tested my tap water which came out to a 8. I do have some granite rocks in the aquarium which I did do tests on and cleaned them before I set the tank up. Are the rocks the reason that the PH has jumped up? what should I do to help stabilize the PH or am I over reacting (everywhere I have read said 6-8ph for an Oscar). Thank you for everyone's help and opinions!

 

How large are the water changes you are doing? what other fish are in the tank?

 

How large are the water changes you are doing? what other fish are in the tank?

i did a 65 a couple days ago but my usual is around 25-30%. He is the only fish in the tank

 

If the rocks are granite it they should not be increasing the pH. What substrate do you have? Ideally the oscar would do best in softer water with a neutral or slightly acidic pH. I am sure many tank bred ones are kept at a higher pH, but I think I have read that they are then more vulnerable to Hexamita / hole in the head disease.

 

If the rocks are granite it they should not be increasing the pH. What substrate do you have? Ideally the oscar would do best in softer water with a neutral or slightly acidic pH. I am sure many tank bred ones are kept at a higher pH, but I think I have read that they are then more vulnerable to Hexamita / hole in the head disease.

the substrate is a coarse sand. I got it at the aquarium shop. I can figure out what type if you want.

 

Most likely it will be inert I think. Not sure why your pH is increasing, or even if it is as I am not sure that the tests are that accurate.

 

Kh keeps pH stable. Likely your water has some sort of stabilizers to make it less alkaline. When stabilizers wear off, the low Kh triggers a rise in your pH

Find out how to increase Kh, and pH will stabilize

 

Just stop water changing your tank and let it run, monitor your parameters, I suspect that you are over water changing this aquarium.

 

pH goes up after tap water sits because the C02 in the water leaves which raises the pH.

You have high pH water from your tap. It's not your tank causing this.

Take a glass of water from the tap and let it sit over night and measure the pH then you can see that it is the outgassing of C02 that cause the pH rise. This is normal.

Your fish will be fine as long as your tank is cycled and has a good biofilter.

 

When stabilizers wear off, the low Kh triggers a rise in your pH

low KH, low pH.

It's most likely the precision of the test. 8 vs. 8.3 is within the error margin.

 

Just stop water changing your tank and let it run, monitor your parameters, I suspect that you are over water changing this aquarium.

With a heavily planted tank this might be OK, but in this case I doubt that the tank is planted, I'm sure nitrates would become too high and this would be an additional risk for the oscar?

 

low KH, low pH.

It's most likely the precision of the test. 8 vs. 8.3 is within the error margin.

Thank you, Trusty Mac

I know low KH causes instability in pH, but I thought it was also a cause of pH change, high or low? That's what research said, but as the saying goes, don't believe everything said on the internet.

So DuckDuckGo failed me again I guess :/

 

I know low KH causes instability in pH, but I thought it was also a cause of pH change, high or low?

It does not cause instability by being low or non-existant. The feared pH-crash happens only in a handful of scenarios.
The most common is not doing waterchanges in naturally soft water, with no live plants and high stocking density. So if the pH of the tap is below 2° and the water isn't changed in a long time nitrate accumulates which is dissolved as nitric acid and lowers pH, eventually neutralizing KH completely. That's when the crash happens.
The other common situation is when people mess with the levels and use pH-down products or straight up acid on relatively soft water in the tank itself instead of pretreating it.
The third is very soft source-water, soil and CO2 injection.

And if in doubt: In low or no-KH water just small quantities of humic substances buffer pH sufficiently.

There is a lot of misinformation going around, as there are still many people sticking to outdated info they learned decades ago, information provided by companies that produce water additives or reading outdated books. Biggest factor is misinformation spread by manufacturers still. And of course all of this is regurgitated over and over.

So DuckDuckGo failed me again I guess

A search engine has no influence on the quality of the website it finds.

 

I imagine your tap water is what we call "liquid rock". This is fine for most captive bred fish as they are hundreds of generations from the soft waters of the rainforest and can breed in harder water of dirt pond in Asia.

 

Thanks for all of your guys help !!