Someone please help on receding chalices

[peterhong]

My chalices have been receding and bleaching one by one slowly. However my sps are doing extremely well. Tank size 120 gallons.
My parameters are:
1.025 salinity
Alk 6.5
Mag 1000
Phosphate .06
calcium 400
I am running carbon, Gfo and doing 20 gallons water changes every week. What's wrong with my tank? Thanks in advance.

[docbattysreef]

I've noticed that many LPS respond poorly to mg levels lower than NSW. Slowly bring your mg up to about 1350 and see if that helps.

[betamed]

alk is a bit low too.

[MechEng99]

Yes, your alk/mag are low. What's your lighting? Are you feeding? Flow? Need more info.

[peterhong]

I am running 5 hours a day on ATI T5 8bulbs 3 Coral Plus, 3 Blue plus, 2 Actinic . I feed every two days. My only flow is a Tunze 6105 powerhead.

[betamed]

if the sps are happy light and flow probably are not an issue. So long as they are not being blasted right next to the 6105. I have basically the same fixture and my chalices do fine at all depths running it 10hrs a day.

[rogersb]

I think this should be stickied: http://www.reefcentral.com/forums/showthread.php?t=2081064&highlight=chalice+sticky

It will help with most chalice issues and definitely get your mag up.

[SantaMonica]

Parasite/invert eating them? Might explain the taller sps not getting hurt.

[radksa]

Just was dealing with this issue myself. Mag is way too low, needs to be between 1400 and 1450. Alk needs boosted as well. As for lighting, it is probably too powerful. Try to place the chalices under shade. I have a 6 bulb ATI, 4 blue+, 1 purple+, and 1 true actinic, and it's too bright, even with them on the bottom of a 90 gallon tank (24 in. deep). ATI fixtures and bulbs are much brighter than some people realize, I think. They are great for mod. to high light corals, but not low light corals, IMO. My palys don't do well under those lights, either. My montis love those lights, though. Hope this helps,
Scott