Need Help with Fox and Bubble Coral
 

I bought a bubble coral and a fox coral about 3 months ago at the same time and added them too my tank. Both looked very healthy when I got them but they are both on a slow decline and shrinking in size.
My tank is 2 years, 90 gallon with 10 gallon sump. I have 2 x 250 watt mh lights that are due for a change. I run the mh for 6 hours a day.
My parameters are:
Salinity 1.025
Alk 7.7
Ca 450
Mg 1350
Nitrate 0
Phos 0
I do a 15 gallon water change every 10 days. I had coralline algae growing like crazy a month ago and my alk and mg were a little low but it is stable again and the coralline has slowed down.
I find every few days a lot of my corals look like crap and then they will be fine the next day. I started running some carbon as I thought maybe I was getting a little chemical warfare but it hasn't made a difference.
I moved the bubble and fox last week but they did worse and I moved them back to their original spots. They are at the bottom of the tank in low flow and I wasn't sure the fox was getting enough light but now I am thinking that maybe my tank is too clean. I have been feeding the bubble about once a week and now I am wondering about feeding the fox coral too.
Should I be running my lights longer or is this a feeding issue? I am at a loss as to why they are both not doing well. If I feed the fox coral what is the best to feed it since it has such small mouths. I also notice that they will be open and when I turn the mh lights on they close up and the bubble looks almost swollen but then the next day it is fine. Is this normal?
Any advice much appreciated.
Leanne P

My bubble coral has a mind of its own. Somedays its huge, other days its fairly small. I dont think its anything to really worry about unless it looks like its dying. When they get rid of there waste they shrink up and kinda look like they are dying to. And i dont really feed my bubble anything, it just sorta takes stuff outta the water that i feed my fish. It has probably doubled in size since i got it and i keep it in high light high flow. Good luck

it could possibly be due to too much light,only from my experience I have 3 mother colonies of fox corals and doing great on the bottom of the tank with LEDs same as a large colony of bubble coral,I don't directly feed the corals but do feed the entire tank with a mix of micron food.

I don't think it is too much light as both of them are partly shaded under rocks. I was actually thinking they may not have been getting enough light. I do realize that the corals close up periodically but the bubbles on the bubble coral don't seem to be as big and full as they were when I got it.

Leanne

it took my bubble coral a month or so before it fully adapted to my tank. Id just give it time, it will probably come around.

fox corals do best shaded with very little flow. If the flow is too high for it, try moving it to a better location.

Some lps like some nitrates.....

All my hammer/frogspawn/octo spawn/ torches are thriving and my no3 is 40-60

My Aussie gold torch isn't happy so I'm gonna try dropping my no3 and see if it gets happy

+1 they need low light and turbulence water flow. Mine do best in those spots. Also fox coral take most of the nutrient from the water. Maybe your tank is not dirty enough? Try some reef fuel - it works wonders - just don't use a lot.

Fox coral need higher flow - they are naturally found on reef cliffs with turbulent water

6 hours seems like a very short photoperiod. Most of us run our main lights 8-10 hours I think.

Both my fox and my bubbles like lower light, protection from full blast of flow.