Calling all coral experts…

[Sharkbait19]

Hello,

Apologies in advance for the lengthy post, but I will try to give as much information as possible. For as long as I can remember, my tank has been plagued with coral troubles, and as of recent, things have only gotten worse.
I think it began towards the end of my Fluval 13.5 setup, when polyp extension on all of my LPS corals got shorter, and eventually, they began to close up dramatically and die. At that time, I was convinced there was a chemical reason for this, given that parameters were (fairly) normal and I had five large leather corals packed in the tank. The solution—upgrade the tank.
With the setup of my 40B, I was more strategic in coral placement, making sure to keep corals from growing on top of one another. The old Fluval tank became a quarantine tank for some frogspawns that were in really bad shape. Eventually, everything was together in the 40B and thriving.
For a while, I thought I had coral care figured out. For months, it seemed as though everything was happy and healthy. I began feeding reefroids, and all seemed good, and all the lps were doubling in size, faster than they ever were in the Fluval.
Then catastrophe struck. After one of my regularly scheduled water changes, corals began to close (at first in a natural response to being messed with). Then they continued to recede, and recede, until I was certain they would all die. At first, the solution I found was constant water changes until the corals recovered. That seemed to work for some corals, but others, especially my frogspawn, would continue to do poorly. That is until they were moved into the coral QT for a couple of days. Then, they’d instantly recover.
At first, these instances happened every few months. Then it was every few weeks. Eventually, my stony corals were all living in quarantine more often than when they were in the DT. I came to realize that something had to have been off, which is when I found what seemed to be the source—the water which I used to do water changes had crazy high phosphates. In the tank, they were so high they couldn’t be read on the Salifert test.
So it made sense—get phosphates down, and all should work out. I began doing water changes with RODI water, which took much longer, but there was certainly an improvement in parameters. Even my SPS and torch were looking better. Of course, with constant water changes, nutrients were also bound to go down. So even when phosphates got to a tolerable level, nitrates were also so low that all stony corals continued to do poorly. So my next mission was to get nitrates back up. With this, everything finally started looking how it did months ago. Yet whenever I moved remaining LPS and SPS from quarantine back into the DT, they’d look fine for a day or two, and then every stony coral in the tank would begin to recede. Except now, it’s no longer a slow process, but they are immediately looking near death. Things were getting bad and I didn’t know why.
I began to test water more frequently. Most recently, they were:

Salinity: 1.026
Mag: 1455
Alk: 9.3
pH: 7.9 (not sure why it was so low this time)
Phos: 0.4 (and going down)
Nitrate: 0.1
Calc: 45

Parameters are, admittedly, off from the proper range in the DT. Yet here’s the truly strange part. The QT is, by all accounts, in worse shape. About five months ago, phytoplankton blooms started to plague the Fluval tank, and despite my best efforts left the water an opaque green. Additionally, parameters weren’t very hot either (aside from pH):

Salinity: 1.025
Mag: 1460
Alk: 10.9
pH: 8.2
Phos: 1.5
Nitrate: 0
Calc: 490

By all accounts, this tank should be the death of any corals, especially the more sensitive ones. And yet they still instantly recover as soon as they’re transferred into the Fluval, just as they did months ago. Which brings me back to my very first conclusion. The fact that the corals start to melt back instantly in the DT makes me think that something undetectable by my water tests is causing such a dramatic effect. Additionally, those affected are exclusively stony corals. Zoas close up for a day or two, but my anemones, softies, and gorgonian all continue to thrive. More so, this happens only when the corals are reintroduced to the tank. The zoas look fine at any other time.

As far as the appearance of the corals when this happens, they tend to spit out their mesenterial filaments and recede, exposing as much skeleton as possible. From there, they either recover fine, or, in the case of my euphyllia, melt back and die.

I’ve been wondering what precisely can cause such an issue. Should I send the water in for an ICP test? Should I be testing beyond these parameters? Or, even at these slightly off levels, can there still be such major effect? Why do I not see this in the QT? My source water has rather high iron levels (I don’t know a numerical value), but RO should fix that, right?

Some images from the most recent “meltdown”:

 

[DanyL]

First of all, yes you should send an ICP test when dealing with unknown issues, you shoot wherever your can to find the cause and it is a very effective way to find out if there is a contamination going on.

Second of all - one possible thing I see happen here is the drastic difference in PO4 between the systems.
You see, even in the same tank you never supposed to drastically change your levels like that and when you do it'll have pretty much the same affect you're experiencing right now.

My theory is that your corals already got used to high phosphates and then you aggressively started lowering them in the DT and caused stress. Moving them back into the QT system, where PO4 is still high seemingly reliefs them.

So my suggestion is to slowly try and drift both systems to be closer to each other in parameters, so that the amount of stress moving them back and forth would be reduced.

You mixed up RO with RODI, mentioned "started to use RODI", I'm confused. Can you explain?
Did you use tap water in the past? RO? RODI? Are you testing TDS?

Are you still feeding Reef Roids? If so, you should stop.
You need to be very conservative with feedings in a reef tank, both for coral and fish,
otherwise as you already noticed, it'll fuel your water with nutrients.

 

[Sharkbait19]

First of all, yes you should send an ICP test when dealing with unknown issues, you shoot wherever your can to find the cause and it is a very effective way to find out if there is a contamination going on.

Second of all - one possible thing I see happen here is the drastic difference in PO4 between the systems.
You see, even in the same tank you never supposed to drastically change your levels like that and when you do it'll have pretty much the same affect you're experiencing right now.

My theory is that your corals already got used to high phosphates and then you aggressively started lowering them in the DT and caused stress. Moving them back into the QT system, where PO4 is still high seemingly reliefs them.

So my suggestion is to slowly try and drift both systems to be closer to each other in parameters, so that the amount of stress moving them back and forth would be reduced.

You mixed up RO with RODI, mentioned "started to use RODI", I'm confused. Can you explain?
Did you use tap water in the past? RO? RODI? Are you testing TDS?

Are you still feeding Reef Roids? If so, you should stop.
You need to be very conservative with feedings in a reef tank, both for coral and fish,
otherwise as you already noticed, it'll fuel your water with nutrients.

I had initially used tap water for a long time, a few months ago I finally realized the errors of my ways and switched to RO. I have an RO unit (I’m pretty sure it’s just RO and not RODI. Coral problems had been existing before I began doing RO water changes though. I have not been testing TDS.
I have not been feeding Reef Roids as of recent.

 

[fish farmer]

First of all, yes you should send an ICP test when dealing with unknown issues, you shoot wherever your can to find the cause and it is a very effective way to find out if there is a contamination going on.

Second of all - one possible thing I see happen here is the drastic difference in PO4 between the systems.
You see, even in the same tank you never supposed to drastically change your levels like that and when you do it'll have pretty much the same affect you're experiencing right now.

My theory is that your corals already got used to high phosphates and then you aggressively started lowering them in the DT and caused stress. Moving them back into the QT system, where PO4 is still high seemingly reliefs them.

So my suggestion is to slowly try and drift both systems to be closer to each other in parameters, so that the amount of stress moving them back and forth would be reduced.

You mixed up RO with RODI, mentioned "started to use RODI", I'm confused. Can you explain?
Did you use tap water in the past? RO? RODI? Are you testing TDS?

Are you still feeding Reef Roids? If so, you should stop.
You need to be very conservative with feedings in a reef tank, both for coral and fish,
otherwise as you already noticed, it'll fuel your water with nutrients.

I can relate to the high phosphate tolerance theory. My tank was running 1 to 2 ppm, dark blue on salifert and nitrates 30. That can't be possible....all the corals should be dead....my softies didn't care and my lone lps frammer actually grew in these elevated conditions, big and fluffy and colorful. I started to drop the phos levels down to 0.5 and beyond and it didn't like it, but eventually got used to the lower levels.

 

[DanyL]

I had initially used tap water for a long time, a few months ago I finally realized the errors of my ways and switched to RO. I have an RO unit (I’m pretty sure it’s just RO and not RODI. Coral problems had been existing before I began doing RO water changes though. I have not been testing TDS.
I have not been feeding Reef Roids as of recent.

The DI in RODI stands for the deionization stage(s), that are comprised of DI resin(s).
They are used as the last stage to treat trace TDS left over by the membrane.

The reason why we use RO/DI water and test TDS is because it may contain harmful elements which can cause various problems, similar to what you're experiencing. TDS stands for Total Dissolved Solids and gives a number to the amount of dissolved elements in the water, however it does not tell you what elements were found.

While softies aren't as sensitive as other types where we target TDS 0, some elements will most definitely hurt them, and because you used tap water originally we will not be able to currently assess wether a DI stage is required or not.

I believe an ICP test will direct you to the right path and expose any contamination, there are a few companies that offer a test for both your tank water and RO/DI, you might want to test both if your'e at it.

Until we have any further information, I stand still to my belief that the difference between PO4 is one of the main causes of stress you're experiencing, and closing the gap between the systems will eliminate this variable.
If you are proceeding with this approach, remember to do it slowly, decreasing up to 0.2ppm PO4 per day, even slower if possible. Dosing nitrates alone is an effective method to lower phosphates and will be beneficial in your current state , GFO is another option for dropping PO4, but it is also a very strong binder and should be treated as such, with extreme care. Go Slowly.

 

[Sharkbait19]

I just got a tds meter - my tap is 55 ppm and the RO is at 2 ppm. Obviously the tap is way to high, but for the RO, is that still too much?

 

[rmorris_14]

Do you have any magnets in the DT tank that could be compromised and leaching into the water?

 

[DanyL]

I just got a tds meter - my tap is 55 ppm and the RO is at 2 ppm. Obviously the tap is way to high, but for the RO, is that still too much?

First of all, you're lucky - my tap water is 680 TDS
I ran through filters on the regular to keep TDS 0, yours on the other hand should last quite long.

To your question - do you know what elements are dissolved within your TDS 2 water?
You can either test your water to find out, but even if it's safe to use it wouldn't necessarily be consistent, and thus should be tested regularly.
Your other option is to add a DI stage and follow your TDS measurements and from time to time change the resin/filters.

Another option is the blind option - you take the risk, but will always question yourself when issues appear wether they stem from your RO water, or from another underlaying issue.
This option does work for some people and I wouldn't judge them, but it really depends on the particular elements left in the RO water and the coral they grow.

 

[Sharkbait19]

Do you have any magnets in the DT tank that could be compromised and leaching into the water?

The powerhead is the only thing I can think of (magnet to attach it to glass).

First of all, you're lucky - my tap water is 680 TDS
I ran through filters on the regular to keep TDS 0, yours on the other hand should last quite long.

To your question - do you know what elements are dissolved within your TDS 2 water?
You can either test your water to find out, but even if it's safe to use it wouldn't necessarily be consistent, and thus should be tested regularly.
Your other option is to add a DI stage and follow your TDS measurements and from time to time change the resin/filters.

Another option is the blind option - you take the risk, but will always question yourself when issues appear wether they stem from your RO water, or from another underlaying issue.
This option does work for some people and I wouldn't judge them, but it really depends on the particular elements left in the RO water and the coral they grow.

I’ll go do a test on the RO now.

 

[DanyL]

I’ll go do a test on the RO now.

You'll need an ICP test, home kits are not enough.

 

[Troylee]

You ever check for stray voltage?

 

[Sharkbait19]

You ever check for stray voltage?

Voltage read 0.3-0.4

 

[Sharkbait19]

Updated dt params:

Nitrate: 3
Phosphate: 0.3
Mag: 1440
Calc: 460
pH: 8.2
Alk: 8.4