Stress Coat contains an aloe base and when the water evaporates from the tank and needs replenishing the aloe does not evaporate but remains in the tank. When you dose the refill water with more Stress Coat you are in effect making the concentration of aloe in the tank more concentrated. Since the aloe will not hurt the fish it is not going to kill them but will give the water a slimy feel and eventually the bubbles from any airstone or from the surface action of the water will make the aloe foam as if it were dish soap. It is not dangerous for the fish but Stress Coat needs to be left out of the refill water until a major water change is made and water with no Stress Coat is used to refill the tank causing the concentration of the aloe to drop to a reasonable level. Do not use Stress Coat in water to refill the tank unless it is to replace water in a major water change. Otherwise a non-aloe based product like Prime should be used to keep the bubbling at a minimum. It does foam and look terrible and can scare you to pieces I know I thought I had killed my fish somehow the time it happened to me. It just needs to be watered down with another type of conditioned water. Please don't put water that is not treated with a conditioner in your tank though.

Rose