So, I have been in salt water aquariums on and off since 1995, however my expertise in reef tanks is relatively young (~7 years). I am now facing a problem that I have not faced before. I have a 90 gallon reef tank with a ~20 gallon sump that a few of my SPS corals are STN from the tips down. My online investigation tells me it is most likely related to lighting, however lighting has not changed in the ~2 years my tank has been set up in Florida. Previously in Charlotte NC I had no issues like I am having here. So here are my suspected issues. I had recently built a canopy and placed it on it which precipitated the issue, but was that just the straw that broke the camels back? I have taken the canopy off to put on ventilation, but the STN persists. I checked my circulation pumps and found one that was not working, I took it apart and the magnet had swollen and may be leaching metals into the tank. I also checked the parameters and found my pH at 7.8, calcium ~400mg/L nitrate and nitrite both 0ppm. I do not have a TDS meter to check my output on my RO/DI, but I suspect it must be off. The question I have is what is the most likely suspect? I plan on addressing each issue, but which do I attack first?
STN help!
- Thread starter Junglejim
- Start date
- Tagged users None
BayouReefer
Valuable Member
I don’t know the exact name for it but there is mechanical filters that will help you remove the metals from the tank. First now that you found the issue a water change of 50% will help. The filter is called Poly-Filter.
C. Eymann
2500 Club Member
Need to know full parameters, you listed all but Alkalinity and magnesium.
If your alk is too high with both PO4 and NO3 being 0, it can pose a problem.
It definitely could be the degradation of the impeller magnet leeching heavy metals, but need to know other things as well to eliminate other variables like possible pests. The M.digitata you posted looks like it's free of tissue loss, is this only affecting your Acropora?
If your alk is too high with both PO4 and NO3 being 0, it can pose a problem.
It definitely could be the degradation of the impeller magnet leeching heavy metals, but need to know other things as well to eliminate other variables like possible pests. The M.digitata you posted looks like it's free of tissue loss, is this only affecting your Acropora?
C. Eymann
2500 Club Member
Like BayouReefer said I would maybe look into running a poly filter, just make sure you rinse it with RO really well before you do, It can help remove copper, I'm not sure about other metals though that may have been leeched by the impeller.
I would maybe only recommend doing two 25% WC over the course of a few daysrather than one big 50%, corals are already stressed dont want to increase that stress.
Have you looked for possible pests? Do you dip corals before introducing them?
I would maybe only recommend doing two 25% WC over the course of a few daysrather than one big 50%, corals are already stressed dont want to increase that stress.
Have you looked for possible pests? Do you dip corals before introducing them?
Normally stn at the tips is called Alk burn from high Alk and low nutrients. Having 0 nitrate and po4 is definitely not helping and I would suggest trying to raise them to 5 nitrate and po4 0.05. I would feed very heavy and test daily.
What’s your normally test schedule along with your feeding schedule and what kind of foods do you use?
What’s your normally test schedule along with your feeding schedule and what kind of foods do you use?
OP
OP
Junglejim
Community Member
- Joined
- Apr 27, 2018
- Messages
- 68
- Reaction score
- 36
I unfortunately only test when I have issues, bad, I know. My alk was only ~8.4 (2.8meq/L), but that does not rule out a spike, but the problem persists. I feed a mix of frozen and pellets, I can always feed more.
Do you ever feed the corals like reef roofs or reef chili? Any amino acids?
Jamestown
Community Member
The last time I had lost some frags to STN, noticed the only thing different was that I had cut back on feeding to address some algae issues and increased water changes. I lost a lot of color on my acros through this time as well. Started feeding heavier and everything looks much better. I think my Nitrates were too low.
C. Eymann
2500 Club Member
How are you achieving NO3 and PO4 testing ? kit?
I agree it could be caused by all burn and possibly too low of nutrients. BUT
I'm seeing things that require you to take a closer look. While I have never seen RBs kill an acro, they will cause stress and cause stunted growth and coloration.
What are these? are you sure you have ruled out pests? RBs? BBs? AEFW?
I agree it could be caused by all burn and possibly too low of nutrients. BUT
I'm seeing things that require you to take a closer look. While I have never seen RBs kill an acro, they will cause stress and cause stunted growth and coloration.
What are these? are you sure you have ruled out pests? RBs? BBs? AEFW?
OP
OP
Junglejim
Community Member
- Joined
- Apr 27, 2018
- Messages
- 68
- Reaction score
- 36
How are you achieving NO3 and PO4 testing ? kit?
I agree it could be caused by all burn and possibly too low of nutrients. BUT
I'm seeing things that require you to take a closer look. While I have never seen RBs kill an acro, they will cause stress and cause stunted growth and coloration.
What are these? are you sure you have ruled out pests? RBs? BBs? AEFW?
Now, my nitrate and nitrite are both API test kits, so take that with a grain of salt, I don't believe I have that low of nutrients, but I did recently slow down my feeding schedule and stopped frozen food, so maybe. I have stared at these corals closely and don't see anything that would be considered a pest, but will take a closer look tonight. I can not rule anything completely out. Thank you for the thoughts.
C. Eymann
2500 Club Member
Just pointing things out in that pic that I think should warrant a you to perform closer inspection of the affected corals.
Considering you are using API, I cannot give you any advice regarding said nutrient levels.
If you want to be successful in diagnosing the problem, I highly recommend getting different test kits.
SeaDweller
2500 Club Member
I agree that it appears to be maybe classic alk burn, although your 8.2 dKh is “low”, but may be too high for your current conditions. If your nutrients are truly that low and your alk is that high, it could be the issue all in itself.
OP
OP
Junglejim
Community Member
- Joined
- Apr 27, 2018
- Messages
- 68
- Reaction score
- 36
So I have been thinking about this a little more, trying to back track the changes that I made, the only thing I can think of is I trimmed up some zoanthids that are growing like mad, could they have released toxins? causing the STN?
