Tank has higher pH than tap water, what's the cause?

[MermaidGurl]

I tested my newly filled aquarium after 24hrs, and the pH was 8.3. The pH of my tap water is approximately 7.5. What might be the cause, and how can I lower it in my tank??
Thanks

 

[UntimelyLord]

Hi! Most likely your tap water had CO2 in it and after that had a chance to off-gas the pH is higher. To see if this is the case, leave a glass of water out for 24-48 hours and then test the pH. If you have shells or coral pieces in your tank that can also raise pH. Some rocks can as well.
Driftwood or Indian almond leaves can be added to naturally lower pH. They may also make your water slightly brown.
You could also add RO/DI water to your tap water, say half and half.
It may be easier to just choose fish that are okay with that pH. Live-bearers, for example, will be fine.

 

[MermaidGurl]

Hi! Most likely your tap water had CO2 in it and after that had a chance to off-gas the pH is higher. To see if this is the case, leave a glass of water out for 24-48 hours and then test the pH. If you have shells or coral pieces in your tank that can also raise pH. Some rocks can as well.
Driftwood or Indian almond leaves can be added to naturally lower pH. They may also make your water slightly brown.
You could also add RO/DI water to your tap water, say half and half.
It may be easier to just choose fish that are okay with that pH. Live-bearers, for example, will be fine.

So I tested my tap water after leaving it in a glass for 24 hrs, and the pH turned out to be 8.3 as well. My water goes through a softener, since it's well water. Idk if that would have anything to do with it.

 

[Sheridonia]

I'm dealing with the same issue. I'm starting to buy spring water from Walmart in the jugs to assist with a nice ph. It's taking some time but hoping it works