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Fish/Discus pH level


Hi Richard---I just bought 2 new young Discus (first time owner) & they seem distressed with my tap water's pH level.  I added "pH decrease" a few times but it's still 7.2-7.4.  What's the best way to lower pH to 6.5?  Please help.  They're expensive & I don't want to lose them.



Hi Larry

I get asked this question a lot and the answer is to trash the chemicals you're using and leave the pH alone. Adding chemicals to the water and fluctuating the pH will cause your Discus more harm than trying to keep pH at a certain range. They will adapt to the pH as long as it's stable and the water is clean. Discus have low tolerance for dirty water. Use the same water source each time you change the water.

Make sure there is nothing in your tank such as a rock or other decor that is raising the pH. Make sure there is no excess food or fish waste in the gravel which will also raise your pH. You can add a piece of driftwood to the tank which will naturally lower the pH, but even I don't do that because it tends to discolor the water.

My Discus are just fine in a pH of 7.8 The most important thing to keeping Discus happy and healthy is a proper diet and perfect water conditions. I do water changes in my Discus tank twice a week, and I never add chemicals to any of my tanks other than water conditioner.

Once all the chemicals are out of the water and your pH is stable, your Discus should appear less stressed.

Hope this helps, good luck!



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Richard Hight


I own and maintain several freshwater aquariums from 2 to 180 gallon. I can answer most questions about freshwater aquariums, including setup, cycling, maintenance, compatible tank mates, feeding. Moving? I've moved fish both across town and across the country and can help you get your little aquatic friends to their new home safely. I know and have experience with most freshwater community fish, South American Cichlids and African Cichlids. I don't answer questions about Goldfish or keeping Goldfish with Tropical Fish. I also don't answer questions about keeping crustaceans (shrimp, snails, crabs etc) with Tropical Fish, nor questions about saltwater fish or aquariums. I'm not available to answer questions on weekends, this is when I do maintenance on my own tanks.


Many years of personal experience with fish and aquariums

HSG 2010-2011 prof

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