Help with Favia

[JW3571]

I have a Favia frag that looks near death. I've attached a pic. Here are my water parameters:

Alk 240
PH 8.2
Phosphate 0
Nitrate 0
Nitrite 0
Calcium 400
Mag 820

I know the Mag is quite low. I'm worried i'm not doing the test correctly. It's a red sea mag test.

I've tried moving it under hardly any light or out in light on the sand bed. The tank is a 90g with 30 g sump. I have 2 150w mh and 4 t5ho lights. THe most i've run my mh is 4 hours. It looks like he's bleaching on the outside. I've been feeding the corals with a baster every other day.

[Crawfish00]

Most of my favias are in higher lighting.. I have a 90 also with 2 mh175 and t5hos 2 48" actinic and blue t8 LEDs.. I'm not sure the color of yours brighter colors tend to like more lighting... Also your calcium is low 480 would be much better..it's kinda hard to tell in the pic if it's bleaching or dyeing.. I'd try more light move it up quite a bit and get the calcium up... Just my two cents

[JW3571]

I'll try moving it up. It can't get worse.

[lewk]

I rarely feed any favias in my tank and they're all doing good. Every other day seems like a lot to me.

[Eric45]

If you have a chronic deficiency in magnesium, your corals will not be able to use calcium effectively. You need to get it up to 1200-1400 and you'll find your alk and calc remain much steadier. Also, that your phosphate test reads zero is pretty much meaningless from what i've read. Animals and algae will take up the phosphate before it can be read on a test.

I use lots of gfo to keep it down and everything seems happy - esp. the fast growing favia.

[JW3571]

I was feeding every other day just to see if i could bring him back to health

[Crawfish00]

What are you feeding them??

[JW3571]

I've been doing mysis and something else i got from teh LFS, I'll have to check.

[Sisterlimonpot]

I have a favia that looks the same maybe worse off than yours, I transferred it form a tank that had traces of nitrates (5-10 ppm) into my 125 that I incorporate an ultra low nutrient system (ULNS) with. it has withered to almost nothing. I deduce it to either the lack of 'dirty water' or lack of trace elements like amino acids in the system.