bubble coral

[68shelby]

did my water test today.
ph 8.3
nitrate 1 ppm elos kit
calcium 420ppm salifert kit
nitrite 0
ammonia 0
temp 80 does not fluctuate past 81 or below 80
kh 80
specific gravity 1.024
no algae in my tank so I seldom test for phosphates.
I do on a regular basis stir up the sand, so he could have gotten sand on him, I did lightly blow it off of all the rock work and corals, last night however. And I never directly feed him.