Calcium and PH

Brisbane Lion

New member
Hi all

My PH is constantly about 8.4 Is this too high? Also my calcium is always at least 650. Should I be concerned?

Kind Regards


Premium Member
Calcium that high is a problem. Are you sure the test kit is accurate? What is your alkalinity running? Lots of great links here. This is one of my favorites, but as you can see there is alot of reading there!
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Brisbane Lion

New member
Alkalinity is around 9 so should be okay. I use "Prodac" brand salt. Supposed to be one of the best. It does have high calcium but sometimes I register above 700ppm. Not sure what you mean by "dosed"? I use a refractometer to measure levels and am sure it is accurate.


Premium Member
I've never heard of that salt. If nothing is being added to the water, then the salt is almost certainly the source. This article might help checking the refractometer calibration:

The other possibility is a bad test kit. I might try to get a second opinion. Calcium shouldn't be fluctuating very much on a day to day basis.


Premium Member
There is no reason to believe any calcium level above 450 is going to be beneficial to a tank and may just cause problems in other places.

If this Prodac is suppose to be the best, I'd be concerned what I am paying for all this extra calcium I do not need. :)

I would expect you have good pH. It's pretty warm down under right now and you probably do not have CO2 issues.

What s.g. are you mixing at and how do you measure ?


In Memoriam
How often do you do water changes and how much do you change out?Do you add any calcium suppliment?

Brisbane Lion

New member
Okay.....water changes are done fortnightly.....about 25%. I use a refractometer to measure salt levels and a PH monitor. The salt level stays pretty much between 600 and 700 and no I dont add any supplements. I mix to about 1.0125.