RBTA issues

[Thomas_Guzman_]

I've had my bta for about 8-9 months but these past few months it hasn't been looking too well. It's been losing color and shrinking. I feed it regularly, 2-3 times a week. I usually feed it mysis or a piece of krill. I have a clownfish that used to host the nem but rarely does any,more. My water parameters seem to be okay other than high nitrates. I have t5 lighting that i recently changed the bulbs about a month ago. Not sure what the problem could be. Any information or suggestions would be greatly appreciated.

PO4- 0
NO3- 30
NO2- .2
KH- 7.9
PH- 8.0
MG-1520
CA- 405

Thanks