Low Alkalinity using Kalk

[jsteinmeyer]

I've been dosing kalk for about three weeks now (1.5 tsp per gallon based on BRS calculator). It did a great job increasing my Ca level and stabilize my Ph but KH is trailing. My levels are below based on Red Sea tests:

Ph: 8.1
KH: 6 dkh
Ca: 430 ppm
Mg: 1440 ppm
Phosphates: 0
Nitrates: ~5 ppm
1.205 sg

Any guesses as to why my KH is falling a little flat? Is 6 dkh sufficient at this point? Tank is 5 months with Zoas, a couple LPS and a monti cap and stylophora. No fish as of now.

 

[thegrun]

I would increase the alkalinity with soda ash, then maintain the desired levels with kalk.

 

[mcgyvr]

What salt mix are you using?

IMO you don't have enough corals to even need to be dosing anything..
Water changes alone should keep levels where they need to be..

But yes you can use soda ash or baking soda to raise it back up some but I would want to know what my fresh saltwater alk was and either change salt or target that level..