I have heard nothing but great thing regarding Tropic Marine Pro. I am a Red Sea lady, but the pars it gives are either to high or too low. I do water changes every week on two tanks. I have the Tropic Marine Pro sitting, waiting it's turn. I will introduce the new salt slowly until 100% has been used. I believe it takes 6 weeks to go 100%.After a decade of using IO/RC, and fussing about having to clean the brown film from my mixing vats, I switched to Tropic Marin Pro Reef. I have a much larger mixing tank now, and dreaded the thought of having to lug it out of my basement, scrub it, and set it back up. The BRS investigates sold me on TM/PR. I can now mix up enough saltwater for three water changes, and not have to worry about parameter swings in storage, but most of all... it mixes CLEAN with no residue. Yeah, I'll pay more for those bonus features.