Can I dose these at the same time


New member
My Alk is 7.7 and my Ca is 400. I've got Seachem Alk additive and Seachem Ca additive. Can I do both at the same time to raise my specs?


New member
Yes, one right after the other, just not together. I dose Alk first as I can see it as it disperses. As soon as I can no longer see it I add the Ca. If possible add it to a sump or fuge, if not add slowly to a high flow area.


Premium Member
As mentioned do it in a sump or at least in a high flow area of the tank. If you can wait 5 or 10 minutes in between that would be ideal, if not you will likely be ok anyway.

Randy Holmes-Farley

Reef Chemist
Premium Member
I've got Seachem Alk additive

Which one?

I'd avoid "Marine Buffer" for use as an alkalinity supplement in reef tanks. Seachem Reef Buffer and Reef Builder are OK, essentially being baking soda and baked baking soda. Marine Buffer has borate in it, which is not desirable as a reef additive for alkalinity. :)