Mysterious STN, please help

GnarleyMarley · Aug 31, 2015

Hey guys I have been battling a mysterious stn problem in my tank for the past month or so, and I can seem to figure out what is going on. I'll start out with tank desc. and params, and we can go from there.

Tank= 60 cube with 20g sump Acropora dominant
Equipment: Radion Gen 3 running at 65% max intensity, Reef octo extreme xs200, TLF 550 running Phosban, 1 Tunze 6095, 1 Tunze 6045, 1 Gyre XF130, Mag 9.5 return, Ca reactor

PARAMS
KH= 8.6 (Salfert)
Ca=450 (api... I know lol)
Po4= 0.01 (just dropped it, was 0.26 two weeks ago) [Hanna]
Mag= 1320 (salfert)
Nitrate= 5-10 (api... again I know lol)
SG= 1.025 (calibrated refractometer)

The tank is predominantly acropora with 3 chalice, and 1 blasto

My first guess was pests. I have dealt with AEFW, a couple times in the past, and that was my fear. I have dipped all corals that show stn and have not found any pests (ie. red bugs, AEFW, Hydroids etc..) So after eliminating the pest theory I started checking all my params and equip, I found that my po4 was at 0.26, so I put phosban on line and slowly lowered it over the past couple of weeks. I continued checking everything that I could think of, and I found that my ato reservoir tank was filthy, and my water which was reading 0 (in a bucket after going through a 5stage RO/DI) was reading almost 150ppm in the reservoir. I cleaned the reservoir with vinegar and have been reading 0 out of the reservoir since cleaning it (that was 3 weeks ago). Another problem that I found while checking equip was my radion gen 3 had reset to 100% intensity and I set it back to 65% about a month ago (it was one of the 1st things I checked). I also put some carbon on line at the first sign to rule out any kind of chemical problem.

The only thing that I have changed with my system has been a ATS that was put on line 3 months ago, and a gyre xf 130 that I added shortly after the 1st sign of stn (about 1 month ago). I do regular 10-15gal water changes once a week using fresh RO/DI and reef crystals

I am still having new pieces starting to show signs of STN, it always starts at the base, and slowly creeps upward. When I first noticed the stn I took every coral showing signs out of the tank and cut it 1/4" above the stn line, some of them have healed up and are beginning to plate on the new plugs, while others started to stn again. I have had 3 new cases that have popped up over the past couple days and I am about to rip my hair out!!!

I'm looking for some fresh ideas or things that I may have overlooked. Is it possible that the dirty ato, and elevated po4 caused the problem and even though I have fixed them its still kind of fizzling out? I have only lost 2 corals since this all began 1 was a nice sized blonde caroliana (very finicky coral) and a blue tort frag. I'm simply at a loss. I'm doing another 15 gal water change tonight (as per my schedule) any and all constructive ideas or theories are welcome, I would just love to figure this out.

Also its worth mentioning that while certain corals are showing stn at the base they are still growing at the tips and showing good polyp extension, and color. its a quandary....

Randy Holmes-Farley · Sep 1, 2015

Unfortunately, lots of times these things go unexplained.

Causes can include metal contamination, stirred up bacteria, a disease brought in by a new addition, and some sort of environmental change that the corals didn't like (temp, salinity, etc.)

Clownman727 · Sep 1, 2015

Make sure that your ALK reading is good. I have read that high ALK can cause bleaching from the bottom up. GL.

PaulKreider · Sep 1, 2015

What Randy said, I stopped trying to find a solution after you read so many of these threads, people will tell you every possible problem, from alk being too low, for alk being too high, from phosphate swings, to loose electrical current, to the boogy man and you just cant possibly test them all.

Best advice would be to try and make your levels stable as possible and hope for the best, unless there's a noticeable large variable swing or an obvious pest/culprit, its pretty dang hard to narrow it down.

Tahoe61 · Sep 1, 2015

Still check all electrical equipment.

Check mag floats for corrosion. Loose screws that may have fallen into the tank from lids, canopies.....

Double check reagents for test kits.

Test your replacement water for metals.

Did you post a pH? What is the am before lights on value?

Have you looked into checking ORP?

afamousjohnson · Sep 1, 2015

Have the same prob over here. Experienced now for over a few years and never figured it out?
Crazy when it happens like you say - great color - great pe and still dying from base up all the while. I have even had pieces still show pe up till the last polyp was taken. Always been the biggest thorn in my side with the tank.
GL figuring it out and hope you do

GnarleyMarley · Sep 1, 2015

Ph fluctuates a little even with the reverse light cycle, and is a little lower than what most people strive for. It sits @ 7.7-7.9 even with the 2 stage on the CA reactor I have a hard time hitting that magic 8.2 but I have ran the system at that ph for years and never had an issue.

Someone was telling me about chloramines that may be slipping by my rodi, but after calling the city I found that Charlotte/Mecklenburg does not use chloramines to treat their water, but I bought a new canister and carbon block to put on line.

As for stray voltage I checked for it with a voltage detector and found nothing. I have never checked orp. Isn't orp just a way to check the oxygen level? If so isn't it something that should be good if u are running sufficient circulation and a skimmer?

I only have one magnet in the tank its a piranah and I just took it out last month to clean it and replace the pads and did not notice any corrosion. As for a screw, I guess anything is possible. I will have to look into getting a test to check for metals, any recommendations?

I'm sure the alk is good, I run a CA reactor and check it frequently with a salfert test kit, and I double checked it at a friends house when all this began and was spot on.

GnarleyMarley · Sep 29, 2015

I think I found my problem!!!!!! My bubble counter on my regulator apparently developed a small crack and the water leaked out, followed by all the co2 that was supposed to be going in the tank. That in conjunction with my salfert alk test being wrong is what I think led to my problem.

I tested my salfert alk test tonight with the supplied calibration fluid for the first time. According to the fluid it is supposed to have a dkh of 6.7 but after testing it twice both times read 8.2!! So while I was testing my alk and thinking it was 9-9.5 in actuality it was in the 7-7.5 range. II had gotten kind of complacent and was testing alk kind of infrequently but really steped it up when the problems started, and while everything looked good I believe that the CA reactor had stopped working so the alk and CA was slowly falling which would explain the stn, instead of rtn due to sudden sharp fluctuations.

I have done several h2o changes over the past month and have slowly rose the alk to a 10.5 (which in actuality is an 8.9) I got a new bubble counter and am going to have to go through the reactor calibration again. And try to get everything stabilized again.

Also I'm ditching these crappy salfert test kits this is the second salfert test kit that has been wrong in 2 months (I bought a po4 kit as soon as my problems started and it read 0 while a Hanna read 0.26) and I'm switching to strictly Hanna meters.

So what do y'all think?

Randy Holmes-Farley · Sep 30, 2015

I don't know if that would have been the problem, since an alkalinity of 7 dKH is generally fine. But perhaps the drop stressed the corals.

Let's keep our fingers crossed that you have it solved. :)