need help with SPS loss.


New member
Little background.
180 mixed reef
up and running for just over 2 years.
3 tangs, 2 triggers, 2 pairs of clowns(skunk and ocelloris), LMB, diamond goby.
various corals, rbta's mushrooms. CUC.
3 250 wat MH 14k bulbs

So my issue started about 6 months ago. I had a number of birdsnest, montiporas various frags of other things. All had grown out really well from small frags over the last year. I had 2 birdsnest colonies that grew out to about the size of grapefruits. All my corals and especially my sps seemed to flourish. THen slowly one by one the began to die. THe birdsnest were completely white from the bottom up within about a week. And so it went with all of my sps.

I thought maybe it was my lights because I went with cheaper bulbs, Replaced those and gave it a few weeks and tried a couple small frags of sps, acros and a milli. ok for a few days then blam almost over night totally white. all this time my levels seemed to be ok, cal about 440, alk at 8.4 dkh, nitrates less then 20, salinity and temp and ph right. Did not have a MG kit so I took it in to my LFS and found out my Mg was at 1100. :( So I slowly brought that up to 1400-1450 over about a week or so. got my own elos test kit and checked everything for about a month and tried it again this time with a birdsnest frag. about a week and it seemed fine, then over the next couple days, white, bottom up to the top.

My LFS is great and has given me lots of help and free frags, but cant seem to find anything wrong with my water either. I use 0tds RODI water, do regular water changes. He suggest that I swap out one of my 5 micron carbon blocks with a 1 micron incase we have Chloramine in the water. New filter is on the way. I have a new birdsnest frag that has been solid for almost 2 weeks now with no signs of rtna but im still worried.

Currently my parameters are
cal 440
alk 8.4 dkh
nitrates less then 10ppm
Mg 1450
sal 1.0026
running a carbon reactor, skimmer, filter socks.

SOrry im long winded, but im stumped. I think I have good husbandry, do my water changes, watch my feedings. All my other corals are healthy and growing, fish are happy and fat. I just dont get why over night my SPS would just stop growing and thriving like they were.

Thanks, any advice would be great.


New member
What kit are you using for CA and Alk?

What is your daily Alk swing?

What are you using to maintain your CA/Alk?

You don't mention flow. What is your turnover rate?


New member
CA is api and an IO, both have came out the same as elos. ALk is IO.

Not getting any swing on alk daily. I normally only test it once a day though.

Right now I am using BRS products for alk and Mg and seachem for CA

Flow is a genx pcx 70, so like 1600gph and 4 koralia 4s, 2 on each end


New member
I have a carbon reactor Charles built for me. If that is what you mean by dosing.

Phosphates are .25 according to my seachem kit. Yes im using RODI, 0 TDS.

Get better po4 test done, either buy Hanna Checker(Like 60$) or ask a favor of a local reefer. If that .25 is actually .50 then you found your problem


New member
are seachem's not reliable test kits?

I think I am gonna run GFO in with my carbon, if I am having Phosphate issues that should help Im told.


New member
I have a carbon reactor Charles built for me. If that is what you mean by dosing.

Phosphates are .25 according to my seachem kit. Yes im using RODI, 0 TDS.

Carbon dosing = Vodka, Sugar, Vinegar, biopellets ect.

I agree that you should have your P04 tested on a cholorimeter.


New member
I had similar, if not exactly the same, problems with my birdsnests, lost two really nice colonies because of it.

It sounds like water quality issues, I'd focus on what's going on in your tank now that the RO/DI is worked out.

What kind of skimmer are you running? It should be pretty overpowered for a 180G.

I would strongly suspect the issue is the NO3 levels, coupled with the low ALK and MG. My birdsnests have proven to be much more sensitive to NO3 levels than any other coral, I'd watch that number the closest especially if it's around 10 now there's not much wiggle room.

Also remember that your SPS coral will thrive in lower nutrient environment while your LPS won't.

Good luck!


New member
Thats the odd thing, my nitrates are currently at the lowest they have ever been in my system. When my birdsnest were flourishing the nitrates were higher.

On a good note my current frag of birdsnest has some nice new little growth tips popping up on it. Just keeping my fingers crossed.

I appriciate the info.