STN/Tip Burn?

[JaaxReef]

So... I don’t want to duplicate too much content on here and I’ve been reading a lot of similar posts on this topic.

I’m having a very slowly progressing bout of STN and/or tip Burn over the last two months with my corals and I’m not sure what is causing it.

I definitely try to practice is stability in my tank and I’ve done my best to keep things stable so I’ve just recently started doing a few things one at a time to see if it will help.

Alkalinity over the last 4 months has been consistently between 9.0-9.5 with no large swings that I’ve tracked. I know it is a little on the high end but that is always how I’ve run my system (2.5 years old) with slightly higher nutrients and never had a problem. My nutrients have always been a little higher with 10.0 NO3 and .03 PO4. I’ve been running a skimmer, and the same dose of Nopox for two years (no change) for nutrient control and I’ve had great success with SPS and acros for well over a year.

The only two changes I made in the last 6 months were slowly raising my light intensity by about 10% over the course of a couple months in small increments and everything seemed to be taking well to it. I run two Hydra 26HD fixtures 11” over a 24” cube at about 65% power at peak. I have a more white setting (18k or so) ramping up and down for 7 hours with a 2 hour Blue period with lower intensity in the morning and evening (11 hours total). The other change was that I switched from Aquavitro Fuel to Acropower since I wanted to use a Doser and Fuel requires refrigeration.

Randomly last month I noticed a few corals STN at the tips and or edges and I was worried. I didn’t knee jerk react or make large changes right away. I slowly lowered my light intensity down by about 5% over the course of a couple weeks. Still things are not looking great. After that I took one week to lower my alk to 8.0 from 9.2 to see if it was running a bit too high. So far, no response and things are still declining.

I recently thought maybe there is some sort of contaminant in the water, so I’ve started doing a few 10-15% water changes every other day and running Polyfilter in case there is a heavy metal I can’t test for in the tank. I Dose 3ml of Acropower throughout the day in small increments. I run full strength Kalk in the ATO and dose Tropic Marin All for Reef (not much since consumption has declined with coral health) for anything beyond what the kalk replenishes.

I haven’t seen any progress yet, so I’m hoping things turn around eventually. Corals impacted include acros, montis, cyphastrea, and chalices.

Thoughts?

Current water parameters:
- Alk - 8.1 dkh
- calcium 440
Magnesium 1410
- NO3 8.0
- PO4 .03
- Potassium 415
- Iodine .06

I’ll attach a picture of the worst damage in a separate reply.

 

[JaaxReef]

Full tank shot and most recent pic of the worst damage...

 

[ACF930]

Your main parameters look fine. You could try a ICP test. Also, possibly there was a spectrum shift in your lighting.

 

[JaaxReef]

Your main parameters look fine. You could try a ICP test. Also, possibly there was a spectrum shift in your lighting.

I increased most of the spectrums evenly percentage-wise when I did bump up 10% intensity a while back. Everything was looking good while I did it, but maybe this is just a delayed reaction?

I’m guessing increased white or red might do if?

 

[dwest]

Full tank shot and most recent pic of the worst damage...

I think you’ve done the right things. I would keep alkalinity at 8 and wait a few months. Next thing I would try is stopping nopox to let nutrients increase.

 

[JaaxReef]

I think you’ve done the right things. I would keep alkalinity at 8 and wait a few months. Next thing I would try is stopping nopox to let nutrients increase.

Thanks. Just one of those frustrating things when I was getting such good color and growth a couple months ago... [emoji17].

Funny... I was thinking the same thing. I have my dosing pump set to .5ml increments for Nopox and was considering bumping it down a hair if things don’t seem to be stabilizing in a couple more weeks. On the other hand, my nutrients haven’t really budged in a year or so, I’m kind of doubting that is the issue here...

 

[jda]

That looks like LED burn to me. Turn them down. If you need more PAR, then get some T5s... pretty common issue with acropora tanks and LED where you see a lot add T5s for this very reason. The other thing that some people do is to run all channels at 100% and raise them way up high - this seems to not burn corals maybe because of the Emerson Effect, but nobody really knows.

Healthy acropora can take some harsh conditions for quite some time before they show signs of issues. This can be true with parameters, lights, temp, etc. People often get a false positive when they change something because the acropora look fine for a few weeks or a month, but were starting to go down hill the whole time without showing signs (kinda like clams). Looking back a few months was a good idea.

Long term, if you are going to be heavy into acropora, then NSW level parameters might be a good goal... 7.0, or so, alk, <1 N. I find them to be a lot healthier and able to resist a lot of things when at these levels. If you are using organic carbon and still have residual levels of N and P around 8, then look into some kind of natural thing to help with this (fuge, remote DSB, etc) - 8 is going to be pretty high for the non-easy type of acropora and while it might not kill them, it might not let them be as healthy as possible to overcome other issues.

Check your refractometer if you have not - I imagine that you did. Also, make sure that whatever checks your temp is good. Never a bad idea to double check these.

 

[ACF930]

Thanks. Just one of those frustrating things when I was getting such good color and growth a couple months ago... [emoji17].

Funny... I was thinking the same thing. I have my dosing pump set to .5ml increments for Nopox and was considering bumping it down a hair if things don’t seem to be stabilizing in a couple more weeks. On the other hand, my nutrients haven’t really budged in a year or so, I’m kind of doubting that is the issue here...

Low nutrient issues will typically lead to pale coloration and STN/RTN issues. A NO3 of 8.0 is fine and within the range that I like to keep for SPS (i.e. 5-10). Have you tried PAR testing? I didn't PAR test originally when I setup my tank and was surprised to see the values when I finally did.

 

[JaaxReef]

Great feedback; thank you.

I recently purchased diffusers for the Hydras that reduce harsh shadowing and even out spectrum, so that may help. They also reduce par by about 10%, so maybe that will help too?

I’m thinking the water changes I’m doing might help reduce some nutrients very slowly. My current setup does not reduce, but maintains the current numbers and has been for a year or so. I can certainly just feed less and I bet numbers will slowly come down. I’ve just had issues with paling when it goes below 4ppm NO3... maybe because my lights were set pretty intensely...

I did check salinity and I always calibrate my refractometer before each use. It was at 1.025, but I am also VERY slowly raising it back up to 1.026 with the water changes.

I have an inkbird controller and a couple of good electronic thermometers and temp seems in check. It stays within .5 degrees of 78 F.

 

[jda]

I don't buy into the narrative that colors are bad under lower N and P. Photos below of some of mine at .1N (need IC test to detect any) and P at 1-3 ppb on Hannah Ultra Low. IMO, lights are more to blame for this than low building blocks, but this is not a narrative that a lot of people want to hear. Super low N and P (below seawater levels) can make corals light and contrast more (what you see in European ZeoVit tanks), but there is no chance that they don't grow faster or have death issues since the ocean has very low levels too and stuff thrives there.

If you are trying to feed coral, then stopping can help lower N a lot too. Slow it the key, but you are all over this.

FWIW - it is not high quantity that burns the acro tips, it is quality. The PAR is usually not that high when this happens at around 300-350 where the same coral with more than twice that from T5 or MH will thrive. It is a quality thing that nobody really knows exactly why. A few years back, it was a few different kinds of white diodes that would seriously burn corals (which have not been used in a while), but now the thought is that people are going too blue and without the warmer spectrum to help move energy from PSII to PSI, then you have to keep the levels lower. This could mostly explain why the folks that use them at 100% on all channels get to run more PAR than people who don't. The diffusers will likely help. When people need to add PAR and end up hurting acros with more from the LED, this is where the T5s get added.

 

[JaaxReef]

Low nutrient issues will typically lead to pale coloration and STN/RTN issues. A NO3 of 8.0 is fine and within the range that I like to keep for SPS (i.e. 5-10). Have you tried PAR testing? I didn't PAR test originally when I setup my tank and was surprised to see the values when I finally did.

I don’t have a PAR meter and haven’t tested PAR. I need to. Just haven’t bit the bullet yet. Maybe I’ll rent one or something...

Were you surprised that your PAR was higher or lower than expected?

 

[ACF930]

I don’t have a PAR meter and haven’t tested PAR. I need to. Just haven’t bit the bullet yet. Maybe I’ll rent one or something...

Were you surprised that your PAR was higher or lower than expected?

It was higher than expected. I was getting 300 in some areas of my sandbed (my tank is 25" tall) . I was also getting NO3 0 or undetectable on my Salifert kit. I let it be for weeks since some people have told me that they don't focus on NO3 and hardly test it. Then some of my acros starting STNing. Once I increased NO3 to 5-10 by dosing Potassium Nitrate, everything started bouncing back.

 

[JaaxReef]

It was higher than expected. I was getting 300 in some areas of my sandbed (my tank is 25" tall) . I was also getting NO3 0 or undetectable on my Salifert kit. I let it be for weeks since some people have told me that they don't focus on NO3 and hardly test it. Then some of my acros starting STNing. Once I increased NO3 to 5-10 by dosing Potassium Nitrate, everything started bouncing back.

I think I’m ok in the NO3 Department at 8ppm... but I might lower the light intensity just a little even since I got the diffusors to see how things react.

 

[Jinko]

Id suggest an icp test it will at least show anything out of the ordinary.

 

[JaaxReef]

Id suggest an icp test it will at least show anything out of the ordinary.

Suggestions on where to get it and the brand?

 

[Jinko]

Suggestions on where to get it and the brand?

Api, Triton or marine lab.

I've only used Triton myself, do a Google search and there will be plenty of places to buy from.

 

[JaaxReef]

Things aren’t really improving, but aren’t really getting worse. Maybe it is slowly turning around? I have a couple Acro frags that I think I’ll move to my frag tank that is stable and growing things right now so I don’t lose them while it gets back on track... or should I just leave them out and cross my fingers so they don’t deal with any more changes?

 

[Charlie’s Frags]

I have the same size tank with 2 hydra 52 HD’s 16” above the water

Most of my acros are receiving 350-500 par. Your issues look like high alk and low po4/no3 to me. I had many problems using nopox. I realize you stated everything was fine and this happened all of the sudden, is there any chance your doser over dosed the nopox? I keep my alk around 8.3, no3 fluctuates 20-30, and my po4 I like to keep around 0.15-0.20. I’ve had much faster growth with these numbers than I did with nsw levels, and more importantly, only 1 death in a year.

 

[JaaxReef]

Thanks for the feedback.

I bumped my Nopox dose down and plan to move it to a very minimal level after a couple months. I did bump the lighting down just a hair for the time being given that stressed receding corals typically don’t love high light. I will look into increasing lighting back up slowly after I get things back under control and get more food in the tank and with the steady lower KH in place for a week or two.

 

[JaaxReef]

After 4 15% water changes, lowering lighting by about 10% and feeding more the recession has halted and polyp extension is improving. Either they were hungry or the light was too intense for my alk levels, or a combination of both. Also could have just been something in the water irritating them. Water changes never hurt anything...