Alk discrepancy

[zbrusko]

The Alk in my mixing tub is 7.5. I use Nyos salt and keep it full with the lid on. Its a 20 gallon Brute garbage can. The salinity is the same as my tank, which is 8.0 dKH using the same Hanna checker. Is this right? Is the tank higher due to the rock & sand? I have an algae reactor but no skimmer & just 1 goni that I’ve had for 3 weeks. Thanks.

 

[Randy Holmes-Farley Verified Community Expert]

Might be higher for many reasons. Can you list anything you dose?

Are you tracking nitrate?

 

[zbrusko]

Might be higher for many reasons. Can you list anything you dose?

Are you tracking nitrate?

I am only dosing chaetoGro at the moment. Nitrate floats around 12.

 

[Randy Holmes-Farley Verified Community Expert]

If nitrate declined from a higher value, that would boost alk.

Are you topping off with ro/di?

 

[zbrusko]

Oh, that’s interesting. My nitrates were higher, but I’ve kept it under better control since I got the algae reactor working properly over the last few months. I am topping off with RO/DI.

 

[Randy Holmes-Farley Verified Community Expert]

Oh, that’s interesting. My nitrates were higher, but I’ve kept it under better control since I got the algae reactor working properly over the last few months. I am topping off with RO/DI.

That may be the difference then. :)

It might also be batch variability in the salt, or a testing issue.