pH increases

Question
QUESTION: Nathan -
I have a 55 gal freshwater tank that has been set up for over 1 year. I change 25 of my water/vacuum weekly since my tank is full of mature fish (almost all tetras and 4 danios.I have one piece of driftwood in my tank. My tap water has been at a pH of 7.2 and my fish are acclimated to that pH. Here is the problem: my pH has jumped to 7.6.  Nothing has changed. Any thoughts?  Thanks for your time.

Deb

ANSWER: Hi Deb,

It's natural for tap water to fluctuate once in a while. The pH of rainwater in the winter can sometimes be different from that in the summer. It's bizarre, but hey, it's nature!

If you want to lower the pH, don't use chemicals. Use something natural. Peat moss in the filter will slightly lower the pH. It's natural and cheap, and is found at most fish stores that sell filters.
Also, adding Co2 will also lower the pH.

If you don't have access to either, then you could use a pH lowering chemical, such as Hagen's pH adjust down. Be sure to use very small amounts, and test the water constantly.

Good Luck, and Happy Fishkeeping!

---------- FOLLOW-UP ----------

QUESTION: I called my LFS looking for peat moss. They didn't have it but agreed our water fluctuates a huge amount and he said to use "purified water" which he (conveniently) has at his store for $.35 a gallon and suggested I use that for water changes.
What is purified water? How can I make some for myself? Any thoughts?  Thanks again.

ANSWER: Hi Deb,

"Purified" water can mean many things. The term 'purified' may be one of many things, like distilled, reverse osmosis, etc.

You could buy a filter that attaches to your tap, like the Brita ones you can find at your local grocery store for about $30. Those ones will purify the water, but they will not affect the pH. Instead, they will remove the 'ions' that raise the pH back to the high level, which means that using your own purified water in conjunction with a small amount of pH adjuster will maintain a stable pH. This would be the best option.

If you don't want to buy their water, or get a tap-filtration unit, then your best choice may be to buy those dissolving tabs that neutralize your pH at 7.0. See if these can be found at your local fish store.

You may want to go and try to see if you have a different pet store in your area that deals with fish. In the US, Petco and PetSmart are both excellent choices. They have many locations, and by going to their website, you can check the closest one near you.

$.35 is not too bad of a deal, considering the price of bottled water is high. However, it's rather impractical, lugging huge tubs of water to and fro from the store to your home...

Good Luck, and Happy Fishkeeping!

---------- FOLLOW-UP ----------

QUESTION: Dear Nathan -
Thank you for your continued help!  I purchased some pH lowering chemicals and used them with my 25% water change.  I got my pH perfect last night but this morning it has bounced back up to the original. I am concerned my fish will not be able to take the stress!!

Answer
Hi Deb,

The reason why it bounces back is because the pH 'buffers' in your water are still present. They naturally raise the pH back to their original (high) level. The lowering agent will work for a day or so, and the 'buffering ions' will kick in. The only way to prevent this would be to filter your tap water, to remove the buffering ions. Without the buffering ions, the pH of the water could easily be changed.

The type of filter that attaches to your faucet would work great. They are fairly inexpensive ($30). Used in conjunction with the pH lower chemical, the pH will remain stable.

Good luck, and Happy Fishkeeping!