PH - How high is too high?

[Bailseeker]

Mixed reef 90 gallon long, sump w/ chaeto, skimmer, T5/LED, less than 1 year old, mostly frags growing well.

My water comes from an aquifer with a PH of 8.3 out of the tap. I'm dosing kalk at 1 tbl spoon per 7 gallons with my ATO and about 10ml of soda ash every other day. I use less than 5 gallons of ATO per week. My PH normally fluctuates between 8.4 and 8.55 daily. I have an Apex and calibrate the probe every few months. API PH test kit shows high PH as well. Phosphates are .08 to .12, nitrates at 10, and ALK at 8.3 to 8.5. I want to increase my ALK to 9.5 and intend to use sodium bicarbonate to offset the PH increase.

I searched around, but couldn't find a decent answer. How high is too high for PH? I can easily increase the PH to 8.7 or higher if I wanted to with higher dosing of soda ash and kalk, but would that help or hurt coral growth?

I apologize in advance to people that consistently fight low PH.....

 

[lapin]

pH And The Reef Aquarium

For many aquarists, pH is not something that they have much experience with aside from their aquarium. For many, pH is almost a black box measurement: something to be considered, but whose physical meaning makes little sense to them. This...

www.reef2reef.com