Unexplained RTN???

[ronj]

i recently had a good size acro die off completely.. the whole back side had turned white and by the time i noticed it, it was not salvageable.....i noticed another one was starting to turn white as well, starting at the bottom and working its way up... it is worse now and the entire bottom shas turning white...the lighting is not an issue... the bottom of the corals have been getting enough light...i have good random flow as well...it almost looks like the coral is bleaching rather than RTN'ing....my CA is fine.. i haven't checked my ALK because the test kit that i bought didn't come with everything it was supposed to.......i fragged what i could from the one turning white presently...any thoughts as to what this could be???

 

[Ed Hahn]

copied from Erics notes...

Here is some help from Eric Borneman



Table 1: Known Causes of Coral Bleaching.
The following list has support in scientific studies as contributing alone, in combination, or synergistically to the signs associated with coral bleaching.
Bacterial bleaching - Vibrio shiloi Low light or darkness
Chemicals - pollutants, metals, pesticides, contaminants Endolithic fungii
Ciliates - unknown type and role Hyper salinity
Coccideans - unknown type and role Hypo salinity
High temperature - sustained or short-term increase Drugs
Low water motion (stagnant water, doldrums) Competition
High irradiance - sustained or a rapid increase Sedimentation
Ultraviolet radiation - sustained high levels or a rapid increase Starvation
Rapid change in temperature - higher or lower Physical injury or stress

Above were from Articles from Eric Borneman...

Here are some things I learned from going to club meetings.
bleach from top, usually means too much light too fast or possible broken bulb lens
bleach from bottom not enough light from bottom.

I bookmarked this a long time ago.
I hope it helps.
Ed

 

[twilliard]

Hey Ron
I would look deep into your water #'s

I just lost my Oregon Tort and it was STN from the bottom up.
Its something with the water. I have another turning brown on me.
I recently found that my Kh was at 8 and I typically keep it at 11
I dont know if that was the cause but any change in water will stress a coral.
I too dont think its light but I am almost sure its about the water.

 

[twilliard]

Hey Ed but isnt there a difference between bleaching and STN?
A coral can bleach without loosing flesh??
My Oregon Tort was fluffing off from the bottom up.

 

[ronj]

mine actually doesn't look like it has lost any flesh, just bleached... the temp is a very good possibility!! it fluctuates in the night from 83-75 on some nights.. i recently had a heater producing stray voltage.. the one i have right now can't keep up with the tank size.. i bought another one, but it is smaller than i thought it looked on the internet... i will get a new one and see if that helps...i will also check that ALK

 

[Ed Hahn]

Ron,
Here are goal I set when I dosed for Corals. Calcium 400-420ppm. Alk 2.8-3.5. Magnesium 3 x calcium readings(ppm)= Mag (ppm). FE 400 ppm Cal, Mag should be 1200ppm.
Keep temperature as stable as possible if possible. Stray voltage will bleach SPS also.

 

[ronj]

well, i got the stray voltage problem taken care of.. i also just added a heater, so that is no longer a problem either..i will just have to keep an eye on my ALK..