I am an experienced shark keeper and have always used RO water. But that was on a 300 gal system. Now that I am building the sharks their larger home 3000 gal (give or take) I dred filling it with RO water. That is a lot of waist water to fill that. I have a lot of plants but not that much. lol. So will my guys be ok if I use another form of declination and all that other bad stuff or will I be harming my baby's with it? What do you others with shark ponds use. It took me 4 days to fill just 300 gal. I know corals need RO but do fish and sharks?