Ph Readings Are Weird

I have an almost cycled tank (finally) but have a question about ph readings. First: My tank is a 15 gallon column tank, currently using a Aqeon Quiet 30 filter with additional airstone. Dimensions of tank are 13x13x24 high. I have some live plants and will be adding more soon. I use Flourish Excel liquid. I am just now switching from AquaSafe Plus water conditioner to Prime and Stability prior to finally adding new fish. Ammonia is still just a bit high at.25, Nitrites 0, Nitrates 5. Gh is 60, kh is 0.

Here's my question. Per the API Master test kit, the Ph test range is from 6 to 7.6 and the High Range is from 7.4 to 8.8. When I test my tap water, regular ph is bright blue- off the chart for the regular ph tester. The High ph is 8. When I test my tank water, the regular ph is 6. The High range is lighter than the 7.4 so probably a 7.2. In the past (prior to my tank's meltdown and 2 1/2 months to recycle it) the regular ph was 7.2 and the high range was the just lighter than 7.4 on the high range. I tried using some ph test strip to compare and also get a 6. on it. I plan on taking a sample to my LFS but does anyone have any thought/clues as to what is going on? Should I raise the ph any if the LFS also get 6? I have ordered some green neon tetras and olive nehrite snails which will be shipped this coming week.

 

So tap is 8 and tank is 6. Used to be 7.2-7.4. If you haven't done a water change in over 2 months I would expect the oh to be low. Your tap of 8 could easily off gass to 7ish so a big water change before you add fish should restore it to 7ish.

 

You should get your KH up more, that’s what stabilizes PH. If it’s zero your PH will be bouncing all over.

 

I Had to read that again. Guess I missed that.

 

You should get your KH up more, that’s what stabilizes PH. If it’s zero your PH will be bouncing all over.

Thanks! SO do you have a suggestion for raising the kh. Does baking soda work or should I go back to the lfs? I have everal days before fishies arrive so I'd like to resolve this soon.

 

What substrate are you using?

 

What substrate are you using?

I have aquarium gravel.

 

The 0 kh is an issue. Is it 0 in your tap and tank?

 

So tap is 8 and tank is 6. Used to be 7.2-7.4. If you haven't done a water change in over 2 months I would expect the oh to be low. Your tap of 8 could easily off gass to 7ish so a big water change before you add fish should restore it to 7ish.

I've been doing regular water changes of about 25-30%. The tank had a stable 7.2 ph for 2 years before the meltdown. Even doing the 2 1/2 month restart, I did water changes.

 

Thanks! SO do you have a suggestion for raising the kh. Does baking soda work or should I go back to the lfs? I have everal days before fishies arrive so I'd like to resolve this soon.

I’d do either crushed coral in your filter or use Seachem Alkaline buffer.

 

I’d do either crushed coral in your filter or use Seachem Alkaline buffer.

Thanks, I'll try that.

 

0 KH means you don't have any buffer. And the nitrification process consumes CaCO3 lowering pH.

you can try Aragonite substrate or crushed coral as a buffer.