Reef crystals with sps

[Starry]

My tank uses 1dkh and 25ppm cal per day,, Due to work, i can only do wc every 2 weeks. doesnt matter what salt i use, i'd have to dose. however there is something in rc that my rbtas and sps love, they swell up and hve great polyp extension after wc. i ty to keep at 425 ca and 9dkh.