Tap Water Ph Is 7.5, But Tank Ph Is 8.2

[rust81]

My tap pH is 7.5, yet my tank pH is 8.2. I am running 3 tanks in total and at least 2 of them are showing a pH of over 8. I dont have any coral sand in the tank - so there shouldnt be anything buffering the pH.

Any ideas?

 

[aaronnorth]

rocks that contain calcium can raise the pH

 

[rust81]

I've got no rocks in the tank. Only proper aquarium ornaments and ceramic pots. Bit puzzled really!

 

[Behold]

High CO2 Levels in the tap water.

My water from the tap is 7.8 but if sat for a day changes to 8.5. Test some water that has had time to sit.

As the CO2 escapes the acidity drops or something and the PH rises.

Something like that anyway!!

 

[rdd1952]

Run a glass of tap ater and let it sit or a period of time and then test it (try testing at 6 hours, 12 hours and 24 hours). As mentioned, it can rise.

 

[ronanphilip]

our ph rises a bit too. was wondering why that happened. ill have to try testing after leaving it sit for a while.

 

[joecoral]

it apparently can be to do with water companies buffering the water if you live in a hard water area, as the water that comes out of the tap must be pH neutral, but the buffer can quickly wear off, or so im told...

 

[Bignose]

it apparently can be to do with water companies buffering the water if you live in a hard water area, as the water that comes out of the tap must be pH neutral, but the buffer can quickly wear off, or so im told...

Unless your local water company has a rule about it "coming out neutral" there isn't any real reason for that. Companies with hard water will often acidify it by adding CO2 because more acidic water is less likely to leave deposits on the pipe walls and fixtures. It is also can help minimize dissolving of the pipe materials. Lastly, a swing in pH also helps stress the bacteria and can help kill them (just as an extra step beyond the chlorination). But, the main reason is less deposits in the pipes.

Like I said, I think you've been told wrong, because there is no reason for the water to have to be a pH of 7.0. It is just a number.