Frustrated - 90% of corals dying

[BPiers]

Hi All-
I've experienced a mass loss over the past few weeks that I cannot pinpoint. All of my corals - chalices and many LPS have shown signs of tissue loss and mass recession. The tank params are stable, nothing new added in a long while.
Frequent water changes, carbon, strong flow, over rated skimmer on the tank, even large water changes to try and stop the issue.
The only thing I can think of - is that when I moved (back in February), I added a few bags of new sand (including two bags of Info Pacific Black arag alive) http://www.bulkreefsupply.com/indo-pacific-black-arag-alive-live-reef-sand-caribsea.html
I've noticed that this sand, unlike other tanks I've had in the past, solidifies into bricks within a week.
Could the sand be the issue? I'll be changing another 40% tomorrow.
I've had a cyano problem that I used some chemiclean on a few weeks ago, followed by a 30% water change a few days later.
Thoughts? Fish and all other inverts are ok (snails, harlequin shrimp, etc).

 

[sbash]

I use this page to help ensure my system has target environment levels:

http://reefkeeping.com/issues/2004-05/rhf/

If any of your numbers are off, that is a good place to start. However, to get any real assistance from us, you will probably need to post your measurements for:

Calcium
Alkalinity
Salinity
Temperature
pH
Magnesium
Phosphate
Ammonia
Nitrate

Lastly, nutrients and chemistry aside what about something contaminating the tank? OR Stray voltage?

 

[malira]

What are your parameters? You say stable but, for instance a stable 0 phosphates and 0 nitrates is a starving tank. Which means dying corals. Not that this is you but what are your numbers?

 

[Ty Hamatake]

Lastly, nutrients and chemistry aside what about something contaminating the tank? OR Stray voltage?

+1
I'd check magnets and water used for mixing as well. Any possibility that your RODI unit is going bad?

 

[Salty1962]

You might want to invest in a Triton test. It can tell you if you have a magnet rusting or some other issue you don't typically test for. Mine told me I had a bad Hana Po4 tester, was testing >.01 but my Triton told me my Po4 was .186

 

[jaws789832]

Are you dosing? If your sand is turning into bricks you have a precipitation problem which means your parameters are off somewhere. When I was dosing 2 part I ran into the same problem. My sand would get hard as a rock in some spots. I stopped dosing and just did water changes weekly for a while and the problem went away.

 

[Vincet81]

This sounds dumb but a lot of people overlook to check the water temp. Summer time some tanks run higher temps.

 

[BigJohnny]

Some pics would likely help

 

[mtraylor]

Alkalinity comes to mind. I highly doubt the sand is at fault. Get your parms tested ASAP and you may need to get some new test kits and or second alternate reading of your parms.

 

[saltyfilmfolks]

I'll vote cal and alk. The solid brick thing is weird. Esp after adding so recently.

 

[DDanis60]

I used to get sand solidifying in areas of low flow.

+1 on the stray voltage or possible corroding magnets somewhere in the system. Good luck!

 

[ALbque]

Check your phosphate level, similar thing happened to me.

 

[Daniel Waters]

I've had sand form into almost like bricks in tanks before. I don't believe that is uncommon, and it can happen for a variety of reasons. Most likely the sand is not the issue.

 

[dmw913]

#1 to posting your test results for the measures suggested above so we can help narrow the issue.

Additionally, calibrate refractometer so you are assured salinity reading is accurate. I recently learned the hard way...

 

[Steve McGlamery]

Lights are to strong, I know if I turn my light up too much, my corals washout. Radions.

 

[Hans-Werner]

I make a suggestion for a scenario: You have high alk in your tank that was stabilized by high phosphate concentrations and the corals tolerated it. After you have changed the sand the new sand was low in phosphate, adsorbed phosphate, caused calcium carbonate precipitation in its surrounding which caused the solidification of the sand and the lower phosphate concentration in the water together with the high alkalinity caused the problems with your corals.
To get an idea what really happend we would need some numbers.

 

[Simon Fraser]

+1 on Temp check, our nano crept up a few degrees 'C and corals were stressing badly.

 

[Whasmack]

What are your parameters?
Do you dose anything else? Bacteria?
I'm just asking because I had a similar incident recently where I was dosing MicroBactor7 & Vibrant with mild carbon dosing (2mL per day on a 250g ish system). Nitrates were about 1.0. I couldn't figure it out until I stopped bacteria dosing & carbon dosing; started nitrate dosing to maintain about 2.5 ppm & things are recovering.

 

[VP616]

You say stable but, for instance a stable 0 phosphates and 0 nitrates is a starving tank.

You might want to invest in a Triton test. It can tell you if you have a magnet rusting or some other issue you don't typically test for.

I would agree to posting tank parameters first to try and narrow down the cause. Even the regular test kit numbers would be helpful, even if you decide to get more in-depth with a Triton test, which would be even more precise. Like what was said above, running a stable ULNS with 0 nitrate and phosphate could mean a nutrient deficient tank.

You've said you've done frequent and large water changes to combat the issue. It may be something with your water-change source too. What type of salt mix are you using? RO/DI TDS measurement numbers? How often were the "frequent" water changes? Also when you say parameters are "stable," how often were you testing and what were the fluctuations?