stressed male due to water fogg..

so my 90 gallon tank has been set up a month an a half now almost 2 months.. i have a canister filter for a 100 gallon an a 75 gallon hang on the back filter i also removed the carbon packs from both. i have 3 fish total one blood parrot thats a few inches an a sting ray thats 6 inches around also a small pond algae eater not sure on the kind of fish. it has a fin like a killer whale..lol its black an white.. either way doesnt matter.. with all that said..

so i do a 30% water change once a week an have been doin that for 3 weeks now as it jus settled..

the last time i did a weekly water change 3days ago now the water has been really cloudy an foggy. cant see through end to end.. i have done a 20gallon water change everyday since the weekly an still after every night its cloudy an algae lookin... what can i get an do to make my water crystal clear again without hurting my fish or taking them out?? most of all worried about the stingray an want to clean this up without stressing him out.. thanks alot..

the water test come back fine.. i got the $40 test kit.. jus looks cloudy an crappy..

what should i be testing for...??? im only testing ph , nitrites, nitrates, and ammonia.. all the levels are coming back at 0.. if you have read i have taking out an replaced several gallons daily now for 3 days the water should an is reading clean of harmfull things i heard that kill.. but its cloudy ,foggy, looks slightly light green jus a small tint.. what is safe to get rid of it...??

ohhh an the ph isnt reading 0.... its at 7.0.. so ot should be crystal clear yet its not... an i have cleaned my filters every 2 weeks with tank water.. replaced the carbon with another sponge.. im confused.. is any type of alge killer safe with my stingrays????