Why are my Acros dying?

[strike2867]

A few of my Acro frags seem to just stop having any polyp extension. Some of the others aren't growing at all. A frag of Red Planet has lost mot of its color, polyps are extending less and I fear it may be on its way out. At the same time, my Green Birdsnest sees new growth on a nearly daily basis, with ok polyp extension. An orange Montipora Digitata has grown from a tiny frag to a nice colony, with several more coming. Ricordeas, both Florida and Yuma, are growing very fast. Xenia is growing fast. One thing is it might be the lights. I got the Orbit fixture 2x250 watt when they were on a huge sale. The bulbs in there are original from roughly 7-8 months ago, I have some new Phoenix's ready to go in there. They are on 10 hours a day and a 100 Watts of T5 are on 12 hours a day. The Acros definitely encrust, but no upward growth. I do vodka dosing. There are 5 fish, all pretty small. The largest is a 5-6 inch Lavender Tang. I'm hoping he grows to his 8 inches. My parameters are:

90 Gallon
Nitrate, Phosphate: undetectable
Alkalinity: 10-11 dKH
Ph: 8-8.1(controller with Kalkwasser)
Salinity: 1.026(ATO)
Temp 78.8-81
Calcium: Was 350 according to LFS, I switched to a different Kalk and started dosing Seachem, not sure what it is now.

 

[GhostCon1]

My first bit of advice: cut the MH to around 6 hours (I keep mine at 9, but you have T5 as well) and cut your t5's down to about 9-10 hours.

See how that works for you.

Read through this thread, he tinkered with his photoperiod and had astonishing responses.

 

[strike2867]

My first bit of advice: cut the MH to around 6 hours (I keep mine at 9, but you have T5 as well) and cut your t5's down to about 9-10 hours.

See how that works for you.

Read through this thread, he tinkered with his photoperiod and had astonishing responses.

I've cut the MHs down to 8.5 and the t5s to 11 for a day or two, and then maybe lower. I will pick up some more fish today, see if that helps. Thank you.

 

[GhostCon1]

Noticed something else, try lowering your alk as well, norm. I see is around 8.9-9.2. Corals don't like high alk, but I suggest doing one or the other first, then trying the next. That way you can pinpoint the problem

 

[CichlidMan@<3]

Whats your magnesium? Also, put the new bulbs in. I like to change my bulbs every 6 months

 

[strike2867]

Whats your magnesium? Also, put the new bulbs in. I like to change my bulbs every 6 months

I talked to the LFS, and he also suggested I switch out the bulbs. Should I do it at the same time that I've lowered the photoperiod to 8(staggered). I don't want to shock the tank too much. Also to create more waste I got a Copperband Butterfly. Unfortunately I don't have a Magneseum test kit, but I'm using Kalk +2, which supposedly raises it.

 

[michael.lemke]

Red bugs? I would look...

 

[strike2867]

Red bugs? I would look...

Haven't seen any, is there anything I should look for?

 

[michael.lemke]

Use a magnifying glass and look close for s few min. Tiny red bugs can be a big problem but easy to fix. Good luck and just a possibility, don't freek out.

 

[strike2867]

Just to give an update. I've flooded the tank with fish and turned down the photo period for MH to 6.5 hours. The SPS started growing and coloring up. Thank you all.