hi well no time cuz of studies, i sold all to a reefer keeping only staghorns cuz i like the shape, well, in my tank which i am sure was 50ppm, my SPS majority became green, its true. However my point is nitrate is not as harmful as you think, just that lower levels will definitely increase one's level of success. It is not impossible to keep SPS with 50ppm. Phosphate will kill SPS but not nitrate. Best species to play with when having high nitrate to me is Acro especially from bali. They hold colour pretty well. This is just my 2 cents, to all disbelieving reefers, pls go try out and see for yourselves. I did, some others did. Thats why we know.