Exactly how old is this tank?
I wouldn't add anything to your tank until you get your water chemistry in line.
You should be showing 0ppm for ammonia, nitrate, and nitrite. Your rock should provide enough natural filtration to bring those levels down. You can also do water changes to speed the process along.
Your calcium is quite high, are you dosing anything for Calcium? You may want to consider stopping. Your dKH or alktalinity is also high, 250ppm translates to 14 dKH which is quite up there. You might want to check out
this article for more info on chemistry and the relation between Calcium and Alkalinity.