STN ...frustrated and can't figure this one out!

[pesto]

Need my BRS friends to help me out. I have a 90G mixed reef tank and have a wide-spread STN event happening. I have lost several SPS corals due to STN in the last couple of months. Only change to my tank is the addition of a Reef Octopus 2000 skimmer around the same time the STN began showing up (coincidence?). Also, the tentacles on my SPS are not extending as much as they have in the past. My LPS, softies and leathers all look good. Here are my parameters:

1. Nitrite = 0
2. Ammonia = 0
3. Ph = 8.0
4. Nitrate = 10
5. Carbonate Hardness = 7 dKH
6. Calcium = 400
7. Salinity = 1.024
8. Magnesium = 1350
9. Temp = 79

Any suggestions on the control and eradication of STN from my tank?

 

[this is me]

For one, I would raise the salinity to 1.026. And maybe ALK to 8 or 9dKH(if you're on biopellets, stays with 7dKH). Unfortunately, SPS are very sensitive and can STN from many causes. Large swing in any of your parameters can cause it to STN. I would check the parameters at a different time of the day to check for your system stability.

 

[pesto]

Yes, that is what makes this so difficult. My parameters have been stable and unchanged since November 2012.

 

[Turbosnail]

Low alk will cause STN so I would try and raise it a little like this is me suggested also how are your phosphates? Phosphates can cause STN too. Is it STNing from the top or bottom? If it is from the top I would think bad bulbs or the water may actually be clearer with the new skimmer causing the corals to get more light than they have. This is a long shot though.

 

[stingythingy45]

How old is your heater?
Any chance of voltage in the tank?

 

[GobyWanKenobie]

I'm sure people will disagree, but if it started with the new skimmer, I would turn it down or even off once in a while. Maybe you're stripping something important out of your water and stressing out your corals.

 

[s_kelley]

By any chance could you have had an alk swing? SPS dont like drastic alk changes

 

[pesto]

By any chance could you have had an alk swing? SPS dont like drastic alk changes

Unlikely, my water parameters have been stable and steady for at least 6 months of testing.

 

[pesto]

I'm sure people will disagree, but if it started with the new skimmer, I would turn it down or even off once in a while. Maybe you're stripping something important out of your water and stressing out your corals.

I was concerned about this as well.

 

[pesto]

How old is your heater?
Any chance of voltage in the tank?

My heaters are located in my fuge which is separate from my sump so, unlikely stray voltage would make it into my tank. Maybe but, think it is a long shot.

 

[Brady]

I'm sure people will disagree, but if it started with the new skimmer, I would turn it down or even off once in a while. Maybe you're stripping something important out of your water and stressing out your corals.

I actually agree with this also. Believe it or not I have SPS in my 75 mixed reef and run no skimmer at all and my corals do fine. I actually had a similar problem a couple of years ago. I unplugged my skimmer and was amazed at the results. U can run a tank with SPS in it with no skimmer if u do it right. I think the skimmer is striping out something that was in there before. I'm not saying don't run a skimmer but I would bet your skimmer is the issue. Maybe run a smaller skimmer?

 

[pesto]

I think the skimmer is striping out something that was in there before. I'm not saying don't run a skimmer but I would bet your skimmer is the issue. Maybe run a smaller skimmer?

I am leaning this way as well. I am going to run without it for a while and see what happens.

 

[GobyWanKenobie]

Try it without skimming and see what happens. One of my nanos had a small crash, and the only thing I had changed was my purigen pillow. The one I used was recommended for a much larger tank. After I took it out, things started to recover. Who would have thought your tank could be too clean.

 

[KSC]

It's far more likely that the skimmer pump (or something else) is leaching something onto the water. Skimmers do a lousy job of "stripping" anything out of a tank.

 

[GobyWanKenobie]

It's far more likely that the skimmer pump (or something else) is leaching something onto the water. Skimmers do a lousy job of "stripping" anything out of a tank.

That's a possibility as well. Perhaps "stripping" was not the correct word, but there has to be something in that gunk in the skimmer cup. Maybe it is removing too much of something his tank needs. If the only variable is the skimmer, I would start there.

 

[KSC]

I'd run carbon and do a few extra water changes. Another more likely scenario is that a bunch of detrius in the sump got kicked up during the skimmer change and released something. If in fact you could strip the water of some vital element with a skimmer you would see a very, very slow decline in color. It would be doublful a skimmer could cause stn in such a short time.

 

[Brady]

I'd run carbon and do a few extra water changes. Another more likely scenario is that a bunch of detrius in the sump got kicked up during the skimmer change and released something. If in fact you could strip the water of some vital element with a skimmer you would see a very, very slow decline in color. It would be doublful a skimmer could cause stn in such a short time.

I personally disagree with this. That is exactly what I did when I had issues. I did more water changes and it was even worse because I made the water even more clean that it already was. IMHO I doubt the pump is leeching anything. Many people live and die by a skimmer in a reef tank. I personally don't.

 

[GobyWanKenobie]

There is a good thread on Reef Central regarding parameters and the need for some nitrates and phosphates in the water, elements we normally try to remove. It's a matter of keeping a healthy balance. He was doing good until November when he added the new skimmer. That's 2-3 months. Wouldn't that be a slow decline?

 

[KSC]

I did a little digging because I wanted to see the tank in question. Since the new skimmer was added it looks like nitrates have gone way up. Not sure if this phosphate reading below is correct but .25 is way too high for sps. Most sps keepers try for .03 or less. I'd say your nutrient levels are way too high. Do you know your current phosphate level?

Nitrite = 0
Ammonia = 0
PH = 7.8
Nitrate = 5
Phosphate = .25
Carbonate Hardness = 7dKh
Calcium = 400
Salinity = 1.025
Magnesium = 1300

 

[SteveDola]

I highly doubt that the skimmer is over skimming and stripping the tank. How has it been skimming? good skimmate? Is it more possible that the new skimmer changed the oxygen levels and thus changed your PH? could your corals be struggling with the change in stable PH?

Has your lighting increased? I know you said you were going to add another brick.
DId you take your DSB fuge off line?
Do you dose GFO? or carbon dose?

High P0 4 will cause STN but more likely theyd brown out from a gradual increase of PO4 then die. Are the stonies Ripping from the base up or tip down?

Any suggestions on the control and eradication of STN from my tank?

do a 15%-20% water change and run carbon. give frags to me for safe keeping