bright green water for since the 12th of this month

hi ,i have had my tank set up since june, it is a 40 gallon with about 25 lbs of live rock ,a true percula clown ,scooter blennie ,yellow goby,cardinal banner,royal gramma,3 emerald crabs, a horse shoe crab and 3 hermit crabs, everything was doing fine all tests were great ,until i changed my crushed coral to live sand ,it stayed cloudy for about 4 days then when i thought it was almost clear the water turned a really bright green, so i thought i needed a bigger filter i had a cascade 300 so i got a cascade 700 canister ,thinking it would help ,ha not helping ,if i turn the lights off for a while it helps but i have to leave them off all dAY THEN AS SOON AS I TURN THEM BACK ON IN AN HOUR ITS GETTING WORSE AGAIN, I HAVE EVEN TRIED TO USE ONLY THE BLUE ATINIC IT SEEMS TO NOT HAVE AN EFFECT AT ALL ON SLOWING IT DOWN ,THERES NO ALGAE GROWING ON ANYTHING JUST BRIGHT GREEN WATER ,TOP OF WATER LOOKS JUST CLOUDY NOT GREEN ,BUT FROM THE MIDDLE OF THE TANK DOWN ITS BRIGHT GREEN DOES NOT MAKE SENSE ,I DID A 15 GALLON WATER CHANGE ,IT DILUTED IT ,IT LOOKED BETTER FOR ABOUT 2 HOURS THEN IT WAS BRIGHT GREEN AGAIN ,ive also been putting marine sat in even before this happened because i had an outbreak of hair algae ,i got rid of it by putting in a pouch of phos-x ,i put the same pouch of phos-x in this time and it has not helped maybe it is used up ,dont know what to do at this point ,but i think it is strange that it is only tinting the water bright green ,but no actual algae growing on anything also it is on the glass but it wipes off with just your finger ,i cant leave my light off very long unless i want kill my live rock and i also have a yellow coral polyp,i do not have a skimmer but plan on getting one soon,im not using RO water , my tank stays at 79 degrees ,but like i said i really think this has something to do with the live sand ,help !help! thanks patsy