Some coral dying, others thriving?

[KyleAwesome]

Alright guys, I’ve got an issue I hope you can help me with. I’ve had my IM lagoon 25 setup for a few months now, all of the rock and most all of the inhabitants migrated from my previous two tanks so everything is quite mature. However my beautiful long tentacle torch is losing flesh where the polyps meet the calcified stalk, I have some GSP on the back wall that’s melting (only the lower portion, the higher light areas seem to be doing great) and some xenia that’s also slowly withering away.
 

Params:
pH 8.3
temp 80
salinity 1.026
calcium 420-440 (drops about 20ppm over the week between water changes)
alk 8dkh (when I was testing last week this was lower, closer to 7dkh)
ammonia undetectable
phosphate undetectable

I don’t have a magnesium test kit (I’ve ordered the salifert and it should arrive next week) I also haven’t been testing NO2 or NO3 but will once again.

I am running two Kessil A80’s with the controller, I know that I’m having a hard time finding the sweet spot as some of my zoas are reaching (those closer to the red spectrum) and some have turned an ugly brown (those that were previously green), I’m most concerned about my torch. I don’t care so much about the xenia or GSP however I consider them an indicator species, if they’re not doing well the ecology must be off.
 

The problem is that my other corals are doing great. My two different goniopora’s are beautiful and have full polyp extension, my blastos are all big and puffy, other zoas and mushrooms (rhodactis, ricordea, discosoma) and my hammers are doing just fine.
 

My guess is that I have two issues:
 

1.       I believe the issue with the torch is/was due to flow. Its on the sand bed and until middle of last week was in a higher intermittent flow area (I have a total of about 540GPH turn over) with a standard flared return nozzle on one side and a spin stream on the other. The torch was getting blown around by the spin stream. In the beginning it seemed to do well, but its more recently gotten upset and what I thought might be splitting/branching now seems to be tissue receding. I’ve moved it to the other side of the tank and tried to lessen the direct flow. The torch still closes up a couple times throughout the day for no apparent reason then will extend almost fully. In the few days its been on the other side of the tank I haven’t seen any real noticeable tissue regrowth but it doesn’t seem to be receding any longer.
 

2.       I think the GSP and xenia must be a water quality or perhaps a lighting issue? The GSP issue is more recent. I’ve been fighting the slowly dying xenia for a few months.
 

Its entirely possible both issues are light or water quality related but I feel like I’m going down multiple rabbit holes and not seeing much payback. What do you guys/gals think?

[Clown79]

It could be stability of parameters.

 

Alk dropping will definitely cause issues. You want to see how much/often its dropping.

 

I would test alk right after a waterchange. Then the next day. If there is no change, you don't have daily consumption.

so test until you see a drop.

 

You will need to dose according to the consumption because lps uses up alk alot. Xenia doesn't like low or fluctuations in alk, gsp is a sign something is off.

 

Lighting is another issue. Are the xenia and gsp in low light?

 

The torch sounds like either stability of params or the flow was too strong in it.

 

[BulkRate]

What Clown79 said...  for the longest time I could NOT keep LPS - euphyllia in particular.  My tank's alkalinity levels have always been low-ish and once it gets chronically so even water changes can induce a spike and nudge the more sensitive corals into stress responses.  Get a handle on what your daily consumption by testing once a day at the same time each day for 3-5 days, then schedule your dosing to maintain it at as close to a stable level as is practical.

 

Something like a Hanna checker is really useful for doing so.  Not a shill, just a hater of titration/color charts.  ;-)

 

Also it wouldn't hurt to get a baseline on your magnesium levels... getting that parameter into an acceptable range (in my case a bad salt mix coupled with large macroalgae bioload) was the "ah-ha" moment and turning point for my own tank.

[ninjamyst]

nitrate and PO4 levels?  maybe your tank is toooo clean.

[KyleAwesome]

I've been monitoring the tank daily and noticing that I'll only drop about 10ppm of calcium over the course of a week, but consistently I'll drop .5-1dkh daily. I've started dosing only  seachem reef part B to keep alk at 9dkh. I'm also betting I'm low on magnesium however I'm waiting on my test kit, hopefully arrives tomorrow. Saturday morning I did a 10gallon water change to hopefully bring any other deficiencies back in line. Since the first fill up, I've been using Salinity reef salt, I like how each batch has its analysis on a sticker on the bucket, it used to be enough to get me through without supplemental dosing but that doesn't seem to be the case any longer.  I'm wondering if my drop in alk is due to my melon sized goni? 

 

I'd like opinions on switching to kalkwasser in my ATO instead of the daily dosing. With my alk drop of ~1dkh will I be able to achieve ~10dkh if I replace approx. 4gallons of fresh water weekly through the ATO? 

 

I've also cut my lighting intensity back a bit and so far the GSP is starting to look better, cant tell any difference in the xenia however the torch is still looking iffy. I get 60-70% polyp extension daily however it will randomly fully retract for no apparent reason before opening back up and the flesh is still very far up the tips of the branches and hasnt seemed to show much improvement regardless of where I place it. I've moved it almost up against the glass towards one side most recently, we'll see how it responds to that but my guess is it will continue to slowly wither away. 

[ReefSafeSolutions]

I like using Kalk in my ATO.  I used this calculator to figure out how much I needed and how much per day I would be adding to my system:

 

https://www.hamzasreef.com/Contents/Calculators/KalkContribution.php

 

My alkalinity stays around the 8dkH range, pretty happy with it!

[Clown79]

I like my alk in the 8 dkh range.

 

If you dose only alk, your ca will drop. They work together. As one drops, the other rises. Thats why many use 2 part dosers in equal parts, to keep them balanced.

Ca is important to keep stable as well as alk. A 10ppm drop over the course of the week is still significant.

 

The goal is to keep things stable with the numbers you start with rather than targeting particular numbers.