Yes I would do WC, ur nitrate is way too high..
If I were u I would replace that reef-sun light..out intensity is way too much for aro
WC about 25% 3 times a week untill nitrate down, u could slack once its constant normal..like 5-10ppm
Treat the tank with aquarium salt, kitchen salt works too but I noticed the aro responds better with aquarium salt and they r cheaper than kitchen salt while bumping ur temp to 88F(the number I keep when medicating), how I come up with that number? I grew up at the earth equator LOL
Do not treat it too long..I would say 2 weeks most and do not over dose with salt, we keep FW for crying outloud LOL