I am at a loss with RTN...

Smprc · Nov 17, 2020

Hi all, I am at a loss. I am more bummed to be honest because well, quite frankly I don't know what to do. It has taken me sometime to just get my maintenance routine down. I have been preparing for some SPS corals for over 6 months. Constant 28g water changes every 2 weeks, like clock work. Everything working and stable as I can. RO/DI water...etc...

Alk - 9.2 - hanna
Mg - 1350 - salifert
Calcium 420 - 450 - salifert
Nitrates - .25 - .50 ppm -redsea
Phosphorous 1 - hanna taken today
Temp 78
Salinity 1.026
Salt - Tropic Marin Pro
Lighting - 3 Maxspect ethereals running AB+ spectrum per BRS settings. 11 hours
FLow - 2 Gyre xf - 280 running random at 60% max

Both Alk and Ca are on a doser
I run a fuge...3 hours nightly.

Here is the latest ICP test

Triton Applied Reef Bioscience are the world leaders in professional sea water analysis.

Empowering aquarists around the world since 2008. Click to view shared sea water analysis.

www.triton-lab.de

I can't for the life of me understand why this happens

That stylo has been in the tank for 2 weeks. He is near the top of the tank.
And this started yesterday. I knew it was RTN and today is pretty much gameover.
The only thing I have not tested is PAR. Which I am planning on doing with a seneye.

I will say this. Today I test the Mg it was at around 1280-1290...which surprised me, because the ICP said 1354. That water sample was from Nov 10th.
So today I raised it to around 1370, kind of an accident, but nonetheless....I can't imagine that a Magnesium swing like that going down to 1290ish over a weeks time would do that to the coral. But if thats it, fine and I'll be even more careful.

The only thing that has change in the last 2 weeks is that I have added a whole new CUC. And for the 1st time in I can't remember I did NOT change the water this past weekend.

Anything thoughts?
Thanks in advanced.

here are a couple of other shots from other inhabitants

Reefahholic · Nov 17, 2020

I’m really sorry to hear about your Stylo. I do not think it’s your Mag. So we can likely go ahead and rule that out. Your parameters look good, but if your NO3 is 0.25-0.5 I’d bump it up a little bit. Are you testing with a Hanna Phosphorus ULR? If so, a result of 1 will be 0.003ppm phosphate which could be limiting the coral of needed nutrients.

One thing you really need to do is test PAR and rule that out. If it’s really intense and your nutrients are low you can’t push them with too much light. You could be burning the coral. Did this start from the top or base? Stylo’s are an easy SPS to keep so something is off.

Make sure to double check Temp and Salinity too.

Best of luck man!

Smprc · Nov 17, 2020

I am testing with Phosphorus ULR. I can't say its a perfect testing method considering the whole powder mix and what not, however, I feel its reliable enough to get me a number and check for stability. With that said, the ICP test showed PO4 at .019ppm. Which is pretty low to begin with, so I know my phosphates are low. I gonna try feeding more. I don't have a lot of corals so don't want to dose NO3/PO4, I'd like to somehow raise them through more feeding, lowering the skimmer time and/or shortening the fuge light time.

Charlie’s Frags · Nov 17, 2020

Smprc said:
I am testing with Phosphorus ULR. I can't say its a perfect testing method considering the whole powder mix and what not, however, I feel its reliable enough to get me a number and check for stability. With that said, the ICP test showed PO4 at .019ppm. Which is pretty low to begin with, so I know my phosphates are low. I gonna try feeding more. I don't have a lot of corals so don't want to dose NO3/PO4, I'd like to somehow raise them through more feeding, lowering the skimmer time and/or shortening the fuge light time.

Lower your alk to 7.5 if your po4 is really 0.02.

ScottB · Nov 17, 2020

The Hanna phosphorus test kit is the best there is. But it is the most (user) error prone kit at the same time. Wear nitrile gloves. WIpe down cuvettes with static charged cloth. Store vials with RO water in them.

How old is the system? If it is "newish" I know it can be challenging to keep nutrient available and not over grow algae.

IME, it is just too tricky to keep SPS with nutrients bouncing around 0 all the time. Those numbers are within testing error range of 0.

Miller535 · Nov 17, 2020

Chaswood79 said:
Lower your alk to 7.5 if your po4 is really 0.02.

I agree, your alk is high for such low nutrient levels.

Charlie’s Frags · Nov 17, 2020

And check your par

TDEcoral · Nov 17, 2020

Did you start with dry rock?

Smprc · Nov 17, 2020

Thanks all, yes I did start with dry rock. The tank has been running for a little over 3 years. I agree with the Hanna checker and the potential errors. As I said before the ICP test came back with .02. So I feel that the nutrients are low. I never really wanted to keep a ULN system. Just happen to work out that way. I only have 6 fish. I lost a few to carpet surfing and so I ordered a lid, that took 6 or so months to get to me. At any rate, I have started the whole QT tank and am waiting for that to finish cycling so I can begin stocking the tank again.

I decided to spread out the WC to every 3 weeks, which is why I didn't change it this past weekend.

Question...is it better to lower the alk or raise the nutrients? And if I lower the alk, will that affect the ph?

I will be ordering a seneye shortly to check PAR. (will they be on sale soon

if not then I'll just order today)

I appreciate all the feedback.

flyfisherman · Nov 17, 2020

You shouldnt need to chase numbers for a stylo. I dont think your stable and if you are, get a pack of frags. Trying to judge your ability to keep sps off 1 coral incremental adds is a fools game. Put a classic sps pack of hearty corals in there with different strains. I would stop the water changes for at least a month. See if you can get the frags encrusting. Most likely you are swinging with the change.

Get STABLE