I would say in general, at least every other day, most of the two part systems recommend every day. I dose with Reef Code A & B from Brightwell Aquatics(basically the same as Kent, only a little better, IMO) every day(night). My tank is mostly SPS and it needs it everyday,(no reactor), if you don't have alot of calcium using corals, you could get away with less than everyday, I'm sure. SPS corals will require daily. I hope this helps some. What you need to do is test your water for a coulple of days to a week, at the same time everyday, to figure out your depletion(consumption) rates and dose accordingly to the instructions on the bottle. You need to be testing Cal and Alk mainly when trying to figure this out. It doesn't hurt to be testing for Magnesium also, if mag is below a certain range, under 1290ppm, you will have problems getting the calcium where it needs to be at or slightly above 400-425ppm. If you have any more questions about it, please ask.
