PH dropping

[BrianGray]

First off ammonia is at.25ppm nitrite is 0ppm nitrate is very high ? PH is 6.4
The tank has been established for six months
The last new fish was added two months ago
The tank is a 55g with a wisper 30 60
The last water change was two weeks ago 25%
In it are 3 red zebra 4 yellow lab 2 kenyi 1 socolofi 1 acie 1 greshakei (Albino) 2 Synodontis eupterus
I also have a chunk of coral in their
My questions are
Even after a water change my nitrates are high. why? nitrates out of the tap are 0
Why is my PH always dropping? PH out of the tap is 7

 

[HN1]

Even after a water change my nitrates are high. why? How well do you gravel vac during the water changes?

Why is my PH always dropping? CO2 will gas off and lower pH. Test your tap after leaving it out in a cup overnight.

 

[JohnPaul]

There should be zero ammonia in a cycled tank. So something is seriously wrong. Either your tank is not cycled, or else you have too many fish and not enough filtration to be able to handle the amount of ammonia your fish are producing on a daily basis. Or else you are perhaps overfeeding and uneaten food is being left in the tank to decompose, causing ammonia spikes.

The fact that your tap water has zero nitrates yet you find "high" levels of nitrates in your tank even after your water changes is another piece of evidence that you are overstocked. If 25% water changes every other week aren't enough to keep your nitrate levels in check, then you need to start doing 25% changes every week. Either that, or else use a bunch of fast-growing live plants to act as "nitrate sponges," but of course that is going to require the proper lighting and (perhaps) dosing of fertilizers.

What does "Whisper 30 60" mean. Is that two filters or one?

Ammonia (besides being toxic to fish) is also acidic, so the fact you have ammonia present could very well account for your pH dropping. Also, when you say your tap water is pH 7, is that the reading you get on it after a full 24 hours? I ask because due to the pressure at which water flows through the pipes (which in turn impacts the levels of dissolved gasses), often the pH of water when it first comes out of the tap is different than the pH of that same water after it has been sitting for 24 hours exposed to the atmosphere. So if you haven't checked that, then run some of your water into clean glass, let it sit, and then test pH and see what you get.

The only other things I can think of that cause pH lowering would be certain driftwoods leaching tannins into your water (tannins = acids), the presence of peat in your filter (which you don't mention), or else certain substrates such as ADA Amazonia. Oh, and if it is a planted tank and you inject CO2, that would do it as well.

Those are some of the things I can think of.

 

[BrianGray]

I have some water that had been sitting for two days with no fish PH was 6.4 so thank you both for that
When I do a water change I vacuum as much as I can but I have large rocks for the fish to hide
the filter is for 60g my fish are not full grown but I will ad another filter the same size later for the stock level
when I feed I use the one minuet rule but the flakes sometimes come out to fast
I have four tanks all with the same problem
the planted 20g 3 zebras 5 neon tetras is the the same

 

[mfdrookie516]

have you ruled out a bad test kit? test with some ro/di water or distilled and see what you get... it should read 0 for ammonia, nitrite, and nitrate, and ph should be close to 7 (i think)

 

[HN1]

How often do you feed your tanks?

 

[BrianGray]

I feed once a day
I tested nitrate with my tap water it was 0