GH and KH Levels Of My Aquarium

Question
Hello Karen,
I just recently decided to get my fishtank (20 gallon) running again.  My Ph Level Appears to be a consistant 7.8. my alkalinity is 300< and my Hardness is 300 both of which I want to lower... right? My Nitrate levels are both where they should be... i recently bought 3 guppies and 4 tetra neons, the neons died and 1 guppie as well... is this due to my high levels of hardness and alkilinity? i have been looking for solutions and all i have come up with is distilled water... what would you suggest?

Answer
Dear Kyle,
Your levels of pH, Alkalinity, and GH (hardness) indicate you have 'hard' water. There is nothing wrong with hard water for most tropical fish. This is because fish are very adaptable and can thrive in less than preferred water chemistry, even spawn in it. And it's also a dangerous thing to try to mess with Alkalinity, pH or any of these levels because dangerous ups and downs from adding acidifying chemicals are extremely stressful for the fish. If you add water softening chemicals, very frequently your naturally high alkalinity level will just buffer the water back in just a short time. No matter how much you add of the pH lowering chemical, the Alkalinity will absorb it until it is completely exhausted. And the result is a pH rollercoaster ride and some very stressed fish.

So just leave your pH, KH, and gh where they are now. The reason you might have lost your fish were because the aquarium was relatively newly setup and didn't yet established the bioligical filter (beneficial bacteria) needed to keep the water healthy. Neon tetras and guppies are sensitive to any trace of ammonia or nitrite so if you could check these you may find the real culprit. As a rule, Ammonia should be 0 Nitrite should be 0 and nitrate less than 20ppm.

Have you cycled your aquarium? If not let me know. You'll need to slowly add some hardy cycling fish and test the water daily while making massive water changes should ammonia or nitrite levels be above safe bounds.

I really hope this helps. As long as extremes are avoided, fish do just fine, live long, and breed in less than preferred water chemistry and as long as their aquariums gets plenty of water changes and is warm, they will thrive.

My very best wishes and Welcome back to this relaxing Hobby!
Karen~