water high in nitrates low in ph

Question
Hi, I believe my problem started by overfeeding but the nitrates are high and the water ph is low.  I change the water twice this week so unfortunately  that would be probably more than 25 % It's a 5 gal tank and I have one kissing fish and two strawberry tetra and 1 upside down catfish.  I also tried from the store liquid to bring the nitrated down and also another types to balance the water but didn't work.

Answer
Well i would get a bigger tank like a ten gallon then those fish would be easier to maintain. To get the pH to the right level use Proper pH 7.0 by API to get the pH up and stable. For the nitrates use "Prime" by Seachem to lower them.

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