If its not closed properly water will leak out when the pump us running.
Closed
You may have to check the seals in the multyport on top of the sand filter.
Need more specific info A multi valve pool filter is a common configuration of valve and filter for a swimming pool system. The piping into and out of the filter is attached to a multivale. A multivalve has has several positions. One type of multi valve has six positions: backwash, waste, filter, closed, rinse and recirculate. (These valve positions are used on a DE filter. A sand filter may be different.) Use the filter setting in the nromal operation of your pool. This setting receives water from the pump and directs it to the dirty side of the filter media and then receives weater from the clean side and directs it to the pool. Use the Backwash setting to flush the DE from the filter and to a drain. Use the waste setting to flush water directly from the pump to the drain. The closed position is, well, closed. Rinse? Recirculate?
check the filter
The swimming pool filter and pump will help to keep the water aerated and will filter many of the contaminants out of the Algae are the food for bugs that can live in your pool. If you have an algae problem you may also have bugs. Ideally you need to stop the chain by providing clear and clean water that is free from contaminants. Make sure that your filter and pump are functioning properly and that they are properly sized for your pool. Make certain that the filter is cleaned or changed on a regular basis. A dirty filter won't do much in keeping your pool clean. Skim and vacuum your pool on a daily basis. Leaves and other debris that fall into the pool will decay and become food for algae.
Advice into the filtration of your pool is best answered by a local pool professional, Check with your local pool shop.
You add D.E. to a pool when you do a fresh filter clean. You also add D.E. if you have to backwash your pool more than normal. When you backwash the pool it is also dumping the D.E. out so it needs to be replaced to keep the grids covered so the pool can filter properly. Hope it helped
Most likely the filter. i would check the fingers inside the filter for tears.
If you are getting sand coming into the pool and have a sand filter you may have to replace worn laterals in the sand filter.
Yes. The pool is closed to due AIDS.
Check the grid and manifolds for holes or cracks.
Make sure the filter is operating properly and not dirty - backwash or bump. If chlorine level is high, that is good but you may want to give the bottom a good scrub while filter is operating