My test kit is telling me my PH is 8.4+. I am cycling my tank if that helps any. How damaging can the PH be to an aquarium? How can I fix it?

Are you cycling with or without fish? If with fish, what type of fish? Some types of fish would love your high alkalinity and pH..

If you want to artificially/chemically lower your pH fast you can use a buffer such as sodium biphosphate (Monosodium phosphate) See: Monosodium phosphate - Wikipedia, the free encyclopedia. However, the one negative side effect is that your TDS (total dissolved solids) goes through the roof which might have an overall negative effect, especially, as I've noticed, on many tropical/aquarium plants.

most people on here have told me that as long as you drip acclimate the fish, the ph level doesnt matter much as long as it's stable. the fish will adjust if acclimated correctly

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Its normal for ph to be high when cycling. When there is enough nitrifying bacteria to break down ammonia and nitrite, the ph should go down. Dont be too concern as its still cycling.

If after cycling it is still high, you can try to use sera super peat and soak it in your tank. It will cause ph to drop and its safe to use.

I have wrote about my ph levels when my tank was cycling. You can reference it in my blog.

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I get that value on all my tanks both Fw and marine.

pH rises as carbon dioxide is removed.


therefore high pH just means low carbon dioxide.

If that is because plants are removing the carbon dioxide, that can't be a problem for the fish in fact my fish thrive at those levels.


Just let that tank run and see where pH winds up.
As fish are added the pH could come down due to the increase in carbon dioxide. So not need to add chemicals.

my .02

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fw leiden since 1979, fo salt since 1979, mixed reef 55g 2002-2009. Strong emphasis on the tank taking care of itself. Balanced with plant life, no water changes, tap water, no filters in FW. Only dosing calcium, alk, mag in marine reef tanks. http://www.aquariumforum.com/f15/my-...ods-26410.html
recent tanks (till 2009) 7 years- 10g FW leiden 7 yrs, 55g mixed reef 7, 2 yrs, 20g FW leiden, 10 g fw leiden , 29g mixed reef, current tank 55g leiden