that is definitely getting up there, but with corals and algae growth it should eventually come down a bit, did you ever test your source water before mixing salt??
i would not think it should be that high using ro, but anything is posible, anyhow, if the fw is not that high, then i would look at any suppliments or salts you are using, you cna check it after you mix the salt and see if hte salt made a difference too, in fact it would be a pain, but if the water is much lower, then you could test after all your additions, to find out what is rasing it, and then go from there, but i would start by testing this first(each and every addition til i found what i was doing to get a make up water that is that high ie- salts buffers ph all of them) the make up water has to be high to keep it at that level, just why would be my first question
also, how does your ph and alk test out?