Sudden low pH, with high hardness

[hennaartist]

I have a 55 gallon planted tank (no driftwood) with ropefish, SAE, and angelfish. It's been set up (with these fish) for nearly two years. I do a 25% water change weekly and everything has been fine. A few days ago, I thought something seemed off, nothing in particular made me think that, but I figured I should test the water (I am sorta a test-aholic lol).

I was so shocked by the low pH, that I took a sample over to my lfs (I use test strips). However, they confirmed that my pH was VERY low (at 6), my water was hard, and my nitrates were much higher than usual (not dangerous though).

I haven't added anything new to the tank. I tested my tap water (after leaving it out overnight) and the pH was at 6.8, as usual. I keep limestone in my tank to add hardness, and keep my pH at about 7.2ish.

Im a regular customer (they know me by name) and they were uncertain why there would be a sudden drop. They could only suggest a water change (which I immediately did), and possibly using some pH up. I really don't want to use chemicals, especially when my parameters had been just fine (for almost two years).

Any ideas or suggestions?

 

[Mebbid]

Could be old tank syndrome. I would try doing multiple 50% water changes this week and see how it reacts.

 

[Andy Sager]

There is a correlation between higher nitrates and falling PH. (Your LFS should know this.) I think if you address that issue it will also address your PH issue. I currently have the same issue with a couple of tanks. ( too many fish and too much food with out my keeping track )I just do a daily water change of about 10%-15% ( so as to not change things too drastically too quickly) and my PH is rising. It's back to weekly changes once the levels adjust.

 

[hennaartist]

There is a correlation between higher nitrates and falling PH. (Your LFS should know this.) I think if you address that issue it will also address your PH issue. I currently have the same issue with a couple of tanks. ( too many fish and too much food with out my keeping track )I just do a daily water change of about 10%-15% ( so as to not change things too drastically too quickly) and my PH is rising. It's back to weekly changes once the levels adjust.

Thank you so very much..
I have been feeding a bit more lately (I'm attempting to stop hand feeding, so that I can eventually take a vacation lol). I'll go back to hand feeding, and do some extra water changes until things stabilize.

 

[PNWaquarist]

Your water utility may have also done something differently on their end. Definitely do the water changes as suggested above to see if that helps, though.

If the problem is your tap water, you'll want to get that pH up a little, before your BB go dormant and you get an ammonia spike. Dissolve about 1/4 teaspoon of baking soda into a cup of tank water and add. Repeat every 4-6 hours or so. I'd try to bump it up to at least 6.5.


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