Tissue Necrosis in Frags?

[meverha1]

I've got a weird situation here that I feel like I need some help with.

Biocube 29

Ammonia: 0
pH: 7.6 (steady)
Alk: 9-10
Mg: 1200
Ca: 455
NO3: 30 (high)
Phosphates ??

Lighting: LED (StevesLEDs set at around 60% Blue, 15% white)

Flow: MP10 set at around 60% max. SPS corals have enough flow without getting too much

I dose VSV and run carbon in a reactor.

Soft and LPS corals - perfectly fine. All showing growth over the past few weeks.

Three weeks to a month ago I ordered a SPS frag pack off of ebay. Everything arrived healthy and was dipped appropriately. I started to acclimate them to my lights.

Over the course of the last 5 days 6 of the 7 frags have shown signs of tissue necrosis/bleaching. They are:

Red Acropora robusta
Pink Acropora hyacinthus
Rose Tip Acropora sp
Fiji Birdsnest Coral
Blue Acropora tenuis
Snipers Bubblefum Millepora

The following frags are thriving and showing signs of growth:

Pink Porites
Poker Star Montipora
Blue Montipora Capricornis

Additionally, I had a older, larger Purple Birdsnest frag that had browned up but has started to regain some color and shows signs of growth over the past week. In fact, it looks better today than it has in weeks.

I know my Nitrates are high. I've been doing a series of water changes and dosing vodka to try to get them down. I've searched my tank for any "Nitrate factories" and haven't been able to find any. I'm working on it but my understanding is that high nitrates cause corals to brown or bleach, not lose tissue.

I was feeding Reef Chili and Reef Roids twice a week but have cut back on that because I thought it might be causing nitrate issues. I also only feed the 3 fish in the tank once per day.

I stuck a Poly-filter in the tank and so far it's not turning any alarming colors to indicate copper, etc...

Before anyone asks, it's definitely tissue necrosis, not bleaching. I can see tissue coming off the corals.

Any ideas? I suspect the 5 frags may be a loss but if it's something I can fix I want to fix it to prevent further issues with other coral.

 

[nmotz]

Watch alkalinity closely. Normally I see tissue loss when alk is swinging too rapidly. Otherwise, I'm not sure. Could be parasites? Might want to get out the flashlight at night and look for red bugs/bite marks/flatworms/etc.

Those nitrates are a little high, but that probably did not cause the tissue loss IMO.

 

[meverha1]

Watch alkalinity closely. Normally I see tissue loss when alk is swinging too rapidly. Otherwise, I'm not sure. Could be parasites? Might want to get out the flashlight at night and look for red bugs/bite marks/flatworms/etc.

Those nitrates are a little high, but that probably did not cause the tissue loss IMO.

Possibly parasites but I did dip the corals before putting them in the tank.

Alk has been fairly constant

Looks like the problem is getting worse on the 6 frags that were previously affected.

 

[vinhle00]

if you're saying your Alk is 9-10 and that all your acros are STning/RTN in a 29g tank(volume is probably less than that after you take away rocks,sand). I'm going to take a wild guess and say your acros are dying due to parameters swings specifically your Alk. My advice is to get a better test kit and find out exactly where Alk is and how much it swings in your tank a day then try to keep it as rock solid as possible. Having a smaller tank gives you very little to work with in term of stability.