Wow...you weren't kidding when you mentioned this before. Thats really bad. I wish I could help you out, but I have no clue what the heck is wrong with that tank.
If it makes you feel any better though, one of my 10 gallons is doing the same thing...I clean it and it's clear...and then a few hours later it looks like yours does. I'm having a very hard time seeing my poor platies anymore. Thing is...none of the fish are noticing it, so it can't be hurting them. I'm just the one who is having problems seeing my fishies.
Well....this is going to sound very "Let's get it started in here" <-----rhymes with a word in that phrase.....but, when I do a water change....it gets cloudier.....instantly. Finger that one out!
Should I assume that enough was enough and that you plucked your fish and tore down the tank like a mad man? I can just picture you in a rampage throwing the rocks, grabbing the fish with your bare hands