depending on the rays..... you are fine...unless you get tigers and flower rays, they should be fine with the big ones... just dont do a big one and clean ur filter on the same day 
turkeyboy85;2627676; said:delchlore is sopose to be instant, i always just fill it up then add the dechlore, havent had any problems yet, have even had stingray pups so... guess it works... lol
Nic;2630069; said:place python in tank.... fill with water... then add prime close the tops and walk away...
, and tigers are fine with big wc. I do 50% every 3 days and no sign of stress.