Well my water is starting to get cloudy so I think I should clean the water since this is the 2nd week I had the tank set-up and I heard water changes should occur at least once every week. Is there anything I should know? I heard that I should remove 20-25% of the water and replace it with new water. I have a bottle of StressCoat Conditionar which removes chemicals in tap water so that fish can survive in it. Do I use that with bala sharks? If so, do I put the conditionar while the shark is in the tank? I don't have to remove the shark while I am changing the water, do I? Another thing is that I don't have a gravle vaccume yet so how do I get the left-over food off of the gravle and the droppings of the fish?