aftaer lights came on today it appeared that a majority of my coraline algea was suddenly bleaching. I tested KH and it is showing 230 ppm. this appears to be really high. is this the culprit?
230ppm = about 4.5meq/l or 12dkH. That is rather high, but it shouldn't cause the bleaching you're experiencing. Have you seen precipitation (white cloudiness) in your tank? How are your Ca and pH values? Lastly, how severe is the bleaching event? Often, coralline can look a little pail right after the lights come on.
