BTA's hiding

Hi All,



I'm having issues with my BTA's hiding. They are still attached to rocks, still have colour, but are shrivelled and all out of sight. Everything else in the tank is doing great.



My Params:



Sal - 1.025

DKh - 10

Ca - 460

Nitrate - 0

Phos - 0

Ammonia - 0



Lighting - AI Hydras approx 10 inches above tank



White - 50%

Violet - 90%

Dark Blue - 90%

Royal - 90%

Red - 15%

Green - 15%

UV - 20%

Flow - MP10



Also running carbon, Skimmer, biopellets and fuge with various macro.



Tank has been up and running for about a year, they will accept food, but just refuse to inflate or come out of hiding.



I've thoroughly checked for anything in the tank that might be ticking them off, but nothing.



Am I missing something here?



The only thing I can think of is that my water may be TOO clean? I'm afraid that my filtration is over the top and my low nutrient levels are annoying them? I've read that low nutrient levels can cause them harm.



If someone could chime in I'd really appreciate it!