Alk 13.5 dKH????? Help

Pure Fishigan · Aug 11, 2022

I was testing all my reef tanks 60.2 and a WB 10 cube and alk was through the roof like 12.2 in the tanks themselves
Then I realized I did waterchange yesterday and went to test my mixing can and it tested 13.2!!!!
I am using a Hanna Alk checker and the reagent is still good
and my salt is good 1.026
The salt I use is tropic marin pro reef salt and never had any issues in the past usually mix 7-8
is there any cause for why this happened and how should I go about saving my corals and livestock
any help is appreciated

gbru316 · Aug 11, 2022

The first thing you should do (after you take a step back, and a deep breath) is verify the alkalinity measurement -- either by taking a sample to your LFS or testing with a test kit.

Don't make any changes until you've verified that the 13.2 dKh measurement is accurate.

HBtank · Aug 11, 2022

Yeah that doesn't sound right and more like a bad reading. Most importantly, does it look like it actually jumped 5-6 dKH (i.e. any tank inhabitants stressed)?

Randy Holmes-Farley · Aug 11, 2022

Did you use tap water to make the new salt water?

Pure Fishigan · Aug 11, 2022

Nope RODI from BRS and on way to closest lfs to get it checked

Randy Holmes-Farley · Aug 11, 2022

If you have any RO/DI, you can do an alk test on it, but if it is 0-1 ppm TDS, it is no concern.

NotApplicable · Aug 11, 2022

I use coral pro salt and the all is p dang high in it!

Randy Holmes-Farley · Aug 11, 2022

NotApplicable said:
I use coral pro salt and the all is p dang high in it!

P means phosphate?

Lou Ekus · Aug 12, 2022

Pure Fishigan said:
I was testing all my reef tanks 60.2 and a WB 10 cube and alk was through the roof like 12.2 in the tanks themselves
Then I realized I did waterchange yesterday and went to test my mixing can and it tested 13.2!!!!
I am using a Hanna Alk checker and the reagent is still good
and my salt is good 1.026
The salt I use is tropic marin pro reef salt and never had any issues in the past usually mix 7-8
is there any cause for why this happened and how should I go about saving my corals and livestock
any help is appreciated

As others have suggested here, I would double and triple check the alkalinity measurement. If that turns out to be accurate, I would then check the salinity measurement. If it all checks out, then I would check the calcium and magnesium in the water that is testing such high alkalinity. If the calcium and magnesium is also extremely high, then it points to the salinity measurement being off. If the salinity is correct, and your calcium and magnesium concentrations are in a good range, then the isolated alkalinity measurement becomes more of concern by itself.

That all being said, I would be VERY careful here and not make any changes until I am absolutely certain of the cause of this discrepancy. I never like to say anything is totally impossible. However, it is extremely unlikely that you have a batch of Tropic Marin Pro Reef that is 13.2 dkH at 1.026. So if there is some other reason for this, you need to make the proper adjustment and NOT go chasing values that may be incorrect indicators of what is actually going on. Worst case scenario is that the same incorrect measurement has been causing you to make adjustments in your tanks leading to issues with parameters there that now need to be corrected with great care.

Please let me know how you make out. If everything checks out, I can always get the lot number from you and check our batch controls for alkalinity of that batch. But doing that as a first step will just waste time in getting things resolved, in my opinion.

Good luck and please let me know how you make out and what you find.