I have a 29 gallon salt water with live rock and live sand. I have been performing A water exchange every two weeks about 20%. I have read you should disturb the sand and you shouldn't disturb the sand when doing a water exchange? Which is the best method? When I do disturb the sand my water gets very cloudy - I feel like it clogs my filtration way faster - should I let it settle for an hour or so before Turing on the filtration?