SPS receding from the bottom up

[Donovan Joannes]

Test your water for potassium (K) if nutrients are not the issue and other parameters are inline.

 

[scardall]

I just checked my specific gravity and it's 1.020. It might be a little low. A few other tid bits. Most of my frags seem to have browned out a good bit and their polyp extension, even at night, has been very poor. Alk and Ca+ consumption has dropped off too. The alk spike combined with the new lights I think has done a number on my little pets.

check Magnesium. ULNS systems could use ME Polyp extender.

 

[Lninwa]

I have a bonsai that is now toast due to alk swing. I tested the water from where I bought my nice bonsai so tried to keep my alk at 8.3. I'm using kalk in my ato and my alk was staying around 8.3-8.5. I test alk daily for the most part. My alk shot up to 10 and this is when my bonsai started loosing color from the bottom up. I'm aiming to keep alk at 9 but it's been around 9.5. Ca 420 Mg 1400 No3 5 and P04 is 0-.04.
So Fin Mike I know how you feel. I've heard it's possible to OD on GFO but don't dose it myself so... you need to raise your salinity SLOWLY. Of course keep your alk stable. What do other sps experts keep their KH?

 

[Lninwa]

Oh sorry one other point that surprised me was Sanjay Joshi's nitrates are 50[emoji15] but he has much expertise and a gorgeous reef

 

[alten78]

Wanted to give everybody an update. I tested my water tonight and have the following values. NO3 0.0, KH 9.9, Ca+ 470. I only tested those three as those are the only important ones right now. I'd test po4, but I run GFO and it's going to be zero. I slowly brought my sg to 1.024. I also did two fifteen percent water changes since my last post.

Here is what I think is going on at this point. I know some of you are thinking "DUH", but hear me out so you can follow my logic. I've been convinced that there is a limiting factor in this tank. Something was either munching on my corals (which there is no evidence of) or the limiting factor was the cause of the recession of tissue. I never thought the limiting factor was going to be nitrate. It's the only thing that makes sense at this point. If there is no fertilizer to make the corals grow, then KH is going to be high and Ca+ is going to be high especially since my input of kalk has been so minuscule. There's no uptake because the corals aren't growing . I've got to get my nitrate up.... now how do I do it without overdoing it.

My plan is to cut that photo period back on the sump. Clearly that cheato is out competing the corals for nitrate and immediately locks it up. That's why its growing so much and the corals are not.

I plan to feed more. I am going to feed three times a day. I am also going to feed the corals, but they never extend their polyps anymore, so I'm not sure how effective that is going to be.

I'm not planning on cutting the skimmer back yet, but I may if the other methods don't work. It is oversized for the tank.

I am going to cut my light intensity back to 55% from the 65%.

Until I get the nitrate issue under control (ironic since when someone makes that statement it's usually because they are too high...not too low) I'm not going to easily get the KH stability under control and the recession issue to end.

In the past, I always had high nitrate and my corals grew like gang busters. It was always algae growth I feared would kill the corals. Oh how this drips with irony!

Any other suggestions?

Glad to hear that the light bulb finally went off, even after it was already suggested early in the thread ;). Seriously though, as mentioned earlier and maybe it'll stick this time, read up on nitrate dosing - https://www.reef2reef.com/threads/question-about-spectracide-stump-remover-dosing.213281/

Stop running GFO as well, need some po4 in the tank too. 9.9 dkh is still pretty high for a tank with no nutrients.

 

[a6walter1]

You should try to take your GFO offline, having some phosphate is not a bad thing. Also, I have been dosing Nitrate in the form of spectracide stump remover for the past 6+ months and have only had positive results. I try to keep my NO3 at 5-10ppm, and stopped testing for PO4.

When i mix up the KNO3 (Stump Remover) i mix it 1 TBsp to 1 cup RO/DI. When I dose, I dose 10 mL in my 75 gallon tank to raise NO3 around 1ppm.

Give this a shot, I think you will be pleasantly surprised.