What kind of mechanical filtration media are you using? The cloudiness looks like fine particulates to me. Try some micro-polishing pads after the courser standard pads and it should clear up pretty quick.
If it's not particulates, then it's probably a bacterial bloom. If that's the case, then it came from cleaning your filters a bit too close together and it's just the reduced amount of bacteria reproducing in what is pretty much an overabundance of food for them. It can take time to have it level itself out, but not a big worry in the meantime. I would just make sure you have enough aeration as the extra bacteria will be consuming oxygen at higher-than-normal levels until the extras die off. As it clears, make sure to watch your water parameters. You want to make sure you don't get a large ammonia or nitrite spike from the dead bacteria entering the nitrogen cycle.