SPS Polyp turning white (coral not dying)

[SCiMMiA]

Hi ! my first post here !

I know I will ask a VERY weird question for my first post, I apologize for that...
But let's start. (Skip at the end for the question)

I'll start with my tank parameters because you guys will ask for it anyway

Tank Age: I started logging everything on Decembre 6th 2016 , so the tank is about 2 years old.
Tank Size: 25 Gallon

I keep all these parameters VERY stable daily
Water: RODI 0 TDS
SG: 1.025
Temp: 78 F
Calcium: 430 ppm
Alkalinity: 8.4 dKh
Magnesium: 1400 ppm ( I don't dose, it stays there)
Nitrate: 0 (redsea test)
Phosphate: 0 (redsea test)
I use Purigen, no Skimmer or anything else...
2 inches sand bed (aragonite) and i'm not sure how many pounds of marco rocks.

Little water change have been done, maybe 3-4 small water change in 2 years (I've done them just because I was feeling guilty...)


What's alive:
1 Pygmy Angelfish (1 year , 1 month)
2 Black Ocellaris Clownfish (9 months)
1 Fire Shrimp (1 year , 7 months)
1 Skunk Cleaner Shrimp ( I guess 1 year, forgot to log it)
25 blue leg hermit crab (soon after the startup of the tank, but I bought gradually)
6 Tronchus Snail
2 Turbo Snail
1 Cerith Snail
1 Short Spine Purple Tuxedo Urchin (10 months)

The weird thing is that my only loss I have to date, is a Diamond Goby, he Jumped !
So, I'm guessing I must do something right...

Corals:
GSP
Green Mushroom Ricordea
Red Branching Montipora
Green Hammer
Utter Chaos
Pink Pulsing Xenia
Brown Random SPS frag (I was told it was blue one day, i'm hoping it will turn blue again)

Got these frags 5 weeks ago:
Emerald Green Birdsnest Seriatopora (growing/encrusting)
Purple and White Acropora Plana (starting to get brown tip and loose skin at the tip)
Red Montipora Capricornis (growing)
Green Pocillopora (encrusting)
Purple Bonsai Acropora Valida (growing/encrusting)

Lighting:
Custom LED light with 3 watts LEDs
8 Royal Blue
4 White (2 warm/2 cool)
4 UV
1 Blue
1 Green/Cyan
Every Leds are at 100% but the Whites are at 75%



Ok, here is the question:
Why do the polyp of my SPS turn white ?
My Red Branching Montipora, Emerald Green Birdnest, and the random brown sps, they grow very well, but some of the polyps turn white, especially the new growth ?

I will try to post picture but I don't know if i will be allowed to as it is my first post.
If you can see them, it is not a reflection from the light or over exposure, it is really white where the arrows point.

 

[ndrwater]

1st off WELCOME TO R2R!!

Now that that's out of the way, your corals look fine. Oftentimes, new growth is much lighter or ever white.
Corals also take a bit of time to acclimate to the new tank. Different water parameters, different lighting spectrum and photo period will also contribute to things being different from wherever you bought the corals.

 

[SCiMMiA]

I absolutly agree with you, but I fogot to mention, the Red Branching Montipora, I have it in my tank for 1 year and 3 months !

I would think after that much time it should have been aclimated...
no ?

 

[ndrwater]

I absolutly agree with you, but I fogot to mention, the Red Branching Montipora, I have it in my tank for 1 year and 3 months !

I would think after that much time it should have been aclimated...
no ?

Probably, but... Have you had any weird swings in thinks like ALK or temp? Change anything?
As an example, when I switched from Halide to LED, sereral corals not only changed colors, but had distinctly different growing patterns.
I have also seen where corals grow to close together and chemical warfare ensues...

 

[SCiMMiA]

Nope, I learned by reading a lot of forums and many website on internet that STABILITY is the key to success so I made sure everything is as stable as possible.
So, there was no change in any parameters or lighting since the start of the tank 2 years ago.

The ONLY parameter that can swing, is the PH and this is caused by the Co2 increasing in the basement because we keep the house sealed with the A/C.
This is also temporary since our summer does not last long (3 months), from June to August.
So the rest of the year, no swing.

 

[ndrwater]

Looking back at your water parameters, I noticed zero Nitrate and Phosphate. SPS corals actually do better with a little of both. Say 5-8 Nitrate, and about .02-.03 Phosphate.
Slowly starving due to lack or nutrients would definitely explain the color loss.
Try feeding the fish a bit more and slowing or removing things like GFO for a bit and see if things improve.
Funny how we were all told that Nitrate and Phosphate need to be zero a few years back, and now it seems the opposite is actually true. People are actually dosing both nowadays in systems that have ultra low nutrients that aren't running something like Zeovit

 

[SCiMMiA]

Yeah, I wondered also about no3/po4
I use only purigen, no GFO or anything else.

I am actually overfeeding on purpose to try to keep some nutrient input for about 8 months...

I have GSP and Xenia growing, would not they show sign of lack of nutrient before SPS ?

Also I have no algae but some green dust algae growing on the glass, so I am thinking nutrient input should be good enough if it's growing on the glass. And with all the inverts I have, they must find some algae to eat or they would be dead? But maybe I am wrong.

I would love to see picture of SPS corals that we know 100% they were starving to see if I can match the effect with what I see in my tank.
If I can be 100% sure no3/po4 is the problem, I can easily dose these two.

I have not been able to find any picture on internet that showed the same effect I have with the white polyps.

 

[SCiMMiA]

I had an idea today, I have grown fresh water aquarium plants a lot before.
In aquarium plants, when you give the macro nutrient, NPK (Nitrogen,Phosphorus,Potassium) they grow very well....
My corals grow very well... if they grow, they must photosynthesize enough , so I am guessing they get enough of the macro nutrient, it does not have to be in the form of Nitrate/Phosphate, it can be anything Nitrogen and Phosphorus

If you provide only NPK to plants, they will get deficiency. You can find easily on internet the many deficiencies in aquarium plants.
Those deficiency are caused by not enough of a particular Micro element, or Trace element..

Would it be possible that the whitening of the polyps be caused by an element missing in my water since I don't do much water change ?

I would love to get an ICP water test, but in Canada, we don't have the availability of these test. If someone in Quebec(Canada) knows a way to get our saltwater tested like the Triton ICP Test I would love to know how !

 

[JFrar]

Hey, that could make sense if your tank is year + old and you don't water chagne regularly, trace elements will lower over long swing of time potentially. which leads me to ask what is your method of keeping alk/calc level? I'm not very familiar with different brands of salt out there, i've been rscp for years now. But maybe between salt you use/dosing methods you can make that happen. I think the AB 2 part dosing i use has a lot of trace elements.

A lot of the hobby is a little bit of experimenting. An important part of doing that too is go slow and be patient.

 

[SCiMMiA]

I also use RedSea Coral Pro Salt.... but really, I have changed water only 3-4 times by small amount in 2 years..
I have the same 55 gallon salt bucket from 2 years ago !

I use RedSea Reef Foundation A for calcium and RefSea Reef Foundation B for Alkalinity.
Both in liquid form.

I think foundation A gives strontium with calcium so i should not be strontium deficient..

Don't know about all the other elements...

 

[JFrar]

You can always do a 10-15% water change and just see if that has any effect in the next week or so on the colors. I was looking up to double check myself. the dosing brand i use is E.S.V B-ionic 2 part, which contains a lot of trace elements. I'm kind of in the same boat with water changes. I've done three in 2018 and have a lot of coral.

 

[Zymurge]

I know this is a really laggy response, but I found this searching for my own issue and thought I'd leave my findings for future searchers.

I've had mixed luck with a couple different SPS, where they'd go in healthy, look fine for a couple of weeks but then slowly die. The pattern is that polyps would extend less and less and then not at all in some sections, and that would then eventually be repeated across the entire skeleton. The sections where the polyps vanished were very clearly whitened.

Frustrating, but then one day I saw the culprit, and the OP may have the same. I don't believe it's water chemistry since other LPS, SPS and softies are doing well in both my tank and theirs.

Turns out in my case, my Pygmy Angel has a taste for a select group of SPS. Most lately I caught her slowly but surely picking clean my newest pocillopra. She seems to like to start in one section and work it clean, then move to another and so on until nothing is left over the course of a week or two. The die off pattern seems to be precisely where she is seen nipping. For the most part, she doesn't have interested in most of the other corals, but every now and then a new introduction attracts her eventually.

Since the OP has a dwarf angel listed and nobody else mentioned that as a possible cause, I'd observe and see if you have a similar issue.

 

[SCiMMiA]

After all this time I figured I should update this if someone has the same problem.

My problem was definatly the lack of nitrate/phosphate.

I started a new tank in march 2019 and transfered some of those coral and they have recovered with more N/P in the new tank.

One funny thing is I let the old tank kind of die on itself without any maintenance.

But to my surprise, nothing died !

Corals look very bad but totally alive.
There is a HUGE lack of nutrient input since I dose nothing and feed nothing.

So the SPS left in that tank has ALL it's polyp completely WHITE.

See what happen without any nutrient on this image :

Has you can see in the background, the GSP is still fully green lol, this thing is Unkillable !