STN but why? pictures included

[roll58]

I have some problems with some of my SPS lately (since 2 weeks now), parameters are stable; calcium 500, mag 1480, KH 8.5, PH 8.1. temp 79 (my KH drop to 7 two weeks ago, had some reef builder) test with Salifert

The only thing I changed was the brand of my carbon... I stop using it yesterday to see if it will make a difference. I also bought a Lobo and torch frag from my LFS.

The tip of my montipora digitata started turning brown and now 2 days ago STN. I can see something on my montipora is it a pest... can you identified it. Look like macro dust feather.

Here an overall shot and a macro;

 

[reefkeeper2]

What carbon was it? I stopped using ROX carbon because I suspected it had something to do with the rtn in my tank. I have no definative proof, just a correllation with stn showing up when I changed it.

 

[roll58]

What carbon was it? I stopped using ROX carbon because I suspected it had something to do with the rtn in my tank. I have no definative proof, just a correllation with stn showing up when I changed it.

Its Black Diamond Activated Carbon from Marineland, I used lignite carbon from BRS without problem before.

 

[JSeymour]

Not sure about the STN, the drop in alkalinity may have done it. As far as the pests, they are some sort of hydroid. They do sting, but I don't think they caused the damage. I've noticed similar hydroids before and had an Acropora encrust right over them. They likely moved into the area once the tissue was already gone.

Lots of people seem to have problems after changing carbon. I think it just comes down to figuring out how long each type lasts, changing it before it reaches capacity and not using too much to begin with.

Personally, and many of you may laugh, I use the aquatic gardens brand carbon pouches, one 50 gallon pouch per 75 gallons and change it weekly. Never noticed a problem and seems to work.

 

[batt600]

You and so many people are having this problem this summer. I hear dont know if it true guys that thay add a chemical to the water that kills mosquito larva but is safe for us to drink, this must be what causing problems . Like I said I heard this dont know if its true

 

[reefkeeper2]

Its Black Diamond Activated Carbon from Marineland, I used lignite carbon from BRS without problem before.

I switched from ROX to Black Diamond and my problem stopped. Doesn't make sense does it? Something happens to trigger rtn when carbon and many times GFO is changed in a lot of peoples tanks. After some thought, I think these are the possibilities.

1. Microscopic particles from the carbon (or GFO) circulate throught the tank, settle at the base of corals and trigger stn.

2. The carbon strips organics (or something else) from the water too much and too fast and triggers stn.

3. Bacteria colonize the new carbon (or GFO) rapidly and strip the water too fast of organics (kinda like changing zeolites and using too much) and trigger stn.

4. It's all a coincidence and we are way off base.

Anyone have any ideas to add to the list?

 

[NVfishman]

i am going through the same thing right now probally lost a 5 gallon bucket in acro mini colonys so far. I checked one day and alk was way low 6.5 then I brought it back up in a few days back to 10. I always think it is the alk but I lost some colonies over night. A friend said it might be the rtn or stn tissue from one colony spreading to the next and this might be true as well, as my oregon tort purple monster and yellow tort are all doing great and have extra high flow hitting them so nothing would settle on the colonies

 

[roll58]

I have another theory beside my new brand of Carbon, I started my tank last September, In January I started using Kalkwasser from my auto top off reservoir, my reservoir is a 6 gallons container, I had 2 full tea spoons of Kalk in the reservoir, 3 days later my 6 gallons was evaporate, parameters were stable, so I stayed with the 2 tea spoons every 3 days for 6g. SPS were fine.

But since June I noticed that my evaporation was more like 5 to 6 days for 6 gallons ... summer time? I didn't adjust my Kalk to match the evaporation. among all parameters, only my Alkalinity wasn't stable since June and I started to have some STN... could it be that? :debi:

What do you think?