Chalice Corals with recession and spots.

[havoc_one]

Hi everybody! Any thoughts on what might be causing this slight and relatively sudden recession on both my chalices? We did do our first 10% change with the Tropic Marin coral salt after always using Red Sea coral pro, so used soda ash to adjust alk in the mix to what was in the tank to try to keep it consistent. pH has been around 7.9-8.1 pretty consistently. Nitrites are 10 ppb , phosphorous was 18 ppb. Both acceptable ranges from what I understand. Nitrates are pretty close to 5. All the other corals seem happy. Zoas, leathers, Duncan, GSP.

Alk change has been minimal in my mind. 7.4 a couple days ago. Added small amount of soda ash dissolved liquid. Two days later added another bit to bring it from 7.7 to 8.
Is this too much too quick?
If it is an Alk issue, will it resolve itself after some stability?

 

[fishguy242]

hi,small change in alk ,no prob,best advice i can give, mod flow, mod light,for chalices didn't mention cal,should be around 450