What I've done in the past is just make up some DI water with salt so that its super concentrated. Then slowly add that to the tank until you hit your target.

However, since you're raising it quite a bit (by fishies standards) raise it very slowly. I'd say by 0.001 a day. So take a few days to get it to where you want it. That way they have a chance to acclimate. :biggrin:

If you do a small water change now with 1.025 sg water it will help out your ammonia etc and your sg without hitting your tank too hard. Just dont do any more than 10% or so. Do your daily sump top ups with 1.025 sg water rather than di water until you get to where you want to be. You need to test your Alk. Dont worry too much about the cal its really not that bad and will come down on its own anyways.

You do need to raise your salinity but that will also raise your calcium, since there is calcium in the salt mix. What are you using to maintain your calcium levels?

I don't think it is a big deal having your Ca 485 ppm as long as your alkalinity is O.K. Just don't add any additional Ca until it returns to <450 ppm. The concern with high Ca is it will precipitate on your heater, impellers etc or precipitate lowering your alkalinity. I have had mine drift up to 512 ppm with no ill effects and some try to maintain Ca at 500 ppm to promote coral growth (no proof high Ca actually stimulates coral growth)