PH keeps dropping

[tekjunkie28]

I have a 10 gallon with 4 neons and 6 black neon tetras. I have 1 large sponge and 1 small sponge filter and a seachem tidal 35 (the small one).   I keep doing water changes get and its not raising my pH much and my tap pH is 7.6. I use prime and I think that is part of the issue. I have 1 Java fern and the rest are fake plants.  I ammonia in the tank and I believe its from the stalled/dead nitrogen cycle. Tank is over a year old.. maybe 2. I have no nitrites and nitrates are around when this started.  I have done multiple 50-75% water changes.   

 

I know I can use crushed coral for buffer but I want to learn why this happened and experiment with how to get it back up.  

[Squeegee79]

If your water has a very low carbonate hardness, or kH, it will not be able to retain a neutral to high pH very well. If you google kH you will get 1000 articles that go into way more depth about it than I will here, but essentially it sounds like you need to raise the kH of your water. 

This could mean crushed coral, but there are also products you can add to the water when you do a water change that will buffer the water. I believe that you can even just use baking soda, but I am not familiar with actually using that, so definitely do some research on it before you decide the best way to go.

[tekjunkie28]

My hardness tests out of the tap at 125. 

[quikv6]

tekjunkie...when you say hardness, I'm guessing you are referring to GH.  But it's the low KH that would contribute to PH swings/dropping PH.

[MAC]

Another thing to consider is testing your tap water ph right out of the faucet and then letting some sit in a glass for about 24 hours and test again. That may help get a better understanding of where the true tap ph settles to on its own. 

 

[tekjunkie28]

My kh is unknown. GH is about 125-150. pH after 24 hours is 7.6.   It doesn't drop any.