Monti bleaching...only one side... help please !

[proxy001]

Hello fellow reefers,
I have a bit of a mystery in my reef tank.
Here is some background:
180g, established. New lights installed a couple months ago along with a Monti plate. I was running Radiant on Radion g5xr Pro x5 started at 40%, ramped up to 50%. Most of my hard corals are let's say doing poorly.
Water Chem:
1.024/1.025

Nitrates 10-20
Phosphates (Hanna) 0.2-0.3, controlled with Brightwell . (still fighting)

Now, the vertical side of the Monti turned Snow White, it is away from the flow
The flat , horizontal part, may have lost a bit of color but not white

What is my problem here?
Phosphates? Too much light? Not enough light? not enough flow?

Obviously there is a problem... So I am trying to bring down phosphate and changed my radion template to the SPS AB+ at 50% (lights at 10-11 inches above water)

Any help is appreciated !

 

[brmreefer]

Temperature is a little to high for my liking. I run my tank at around 78

 

[proxy001]

True but how would that explain one side bleaching?

 

[brmreefer]

Not sure, but I had purple monti that started to RTN badly on one side and quickly bleached out completely. This was because of salinity being off due to a refractometer that gave me incorrect readings due to lack of re-calibration. Just mentioned the temp as that is what I initially saw as being a little higher that I prefer.

Nothing more than some considerations towards finding your source issue.

 

[proxy001]

I do appreciate your help !! do you think phosphate at 0.3 can do that??

 

[brmreefer]

I wouldn't think so, but maybe someone else may chime in on that question. I am also thinking zero PO4 would be worse than elevated readings. Just some things to consider when investigating your tank further:

1. Verify readings are accurate with a different test method if possible to validate initial test results. **This one is important for me, and I check a parameter against another back-up test method when warranted.**
2. Make adjustments to one parameter at a time to help identify the source of an issue.
3. Do the adjustments slowly.

Hope you find the cause.

 

[proxy001]

Thank you. yes I do that when a reading is off. It happened very suddenly too. Thinking RTN like you said; interestingly I have several pieces at the same location. The one that bleached is the one with least light and no flow.