spider gasket is bad
The "Rinse" will also take water out, but you should really have a waste setting. Call a local pool company or the maker of your filter system.
Sounds like a leak on the suction side of your equipment.
It sounds like there is a crook seal in there some where.
If the pool is really dirty then it is best to set the filter to waste.
So long as there is water coming through the pump when it is running it doesnt matter what the water level in the pool is.
You vacuum waste from a pool with a pool vacuum connected to a pole to push it around the vacuuming devise is plugged into the suction of the pump. If you wish to vacuum to waste on the other hand you will first have to turn of the pump then turn the lever on the top of the filter to waste. This will dump the water, so don't vac to waste any more then you have too.
most multiports on sand filters have the following settings* Filter Runs the pools water from your pump through the filter media then back into the pool. this is the setting that is nearly always used.* Backwash Runs pool water from your pump over the filter media and out to waste. This removes dirt that has been collected during filtration. A backwash is required when your pressure rises about 10 pounds over the normal pressure. Most sand filters have a clear bubble situated near the multi port where you can see the water running to waste, watch it and you will see that the water is dirty at first run the backwash until it clears then stop the pump. * Rinse Runs pool water from pool through the filter to waste further rinsing the top of the filter media. this should always be done after backwashing to stop cloudy water returning back into the pool * Re-circulate Simply keeps the water circulating from the pool through the pump and back into the pool. It does not put the water through the filter, stops the water from stagnating but still puts it through the static skimmer.* Winter/Closed shuts all the ports and is used when the pool is winterized shut down or to stop water from passing through the valve.* Waste Runs Pool water directly to waste without running it through the filter. This setting if manually vacuuming the pool and the dirt load is too high for the filter to handle. It is also the setting that is used for hand vacuuming when removing settled contaminant and flocculate after flocculating the pool. Never keep the pump running when changing the setting on the multi port as it will cause it to be damaged.
most multiports on sand filters have the following settings* Filter Runs the pools water from your pump through the filter media then back into the pool. this is the setting that is nearly always used.* Backwash Runs pool water from your pump over the filter media and out to waste. This removes dirt that has been collected during filtration. A backwash is required when your pressure rises about 10 pounds over the normal pressure. Most sand filters have a clear bubble situated near the multi port where you can see the water running to waste, watch it and you will see that the water is dirty at first run the backwash until it clears then stop the pump. * Rinse Runs pool water from pool through the filter to waste further rinsing the top of the filter media. this should always be done after backwashing to stop cloudy water returning back into the pool * Re-circulate Simply keeps the water circulating from the pool through the pump and back into the pool. It does not put the water through the filter, stops the water from stagnating but still puts it through the static skimmer.* Winter/Closed shuts all the ports and is used when the pool is winterized shut down or to stop water from passing through the valve.* Waste Runs Pool water directly to waste without running it through the filter. This setting if manually vacuuming the pool and the dirt load is too high for the filter to handle. It is also the setting that is used for hand vacuuming when removing settled contaminant and flocculate after flocculating the pool. Never keep the pump running when changing the setting on the multi port as it will cause it to be damaged.
Filter setting intakes pool water through the skimmer, sends it through the filter (then heater, if any) and back into the pool. Backwash sends pool water through the filter in reverse and dumps the water out for cleaning purposes. In my experience if pool servicing is overdue you may need to backwash several times, running the filter setting a minute or two (without adding DE) in between each backwash. The filter is not really clean until the water runs clear. Recirculate is a round robin water voyage from skimmer to return port bypassing the filter if the pool is piped for this feature. Waste dumps water from the skimmer without going through the filter. Closed prevents water from entering the filter tank and should not be used with the pump running. It is for winterizing and servicing only. Some pools are piped so that the closed setting is used when vacumming the pool (with pump running). Most pools are piped so that the closing off of water from the filter is accomplished by turning a valve on one of the water lines. Rinse: Runs water through the filter in the normal direction and out the waste hose. This helps the sand to compact back down or the DE to settle back into the mesh before you start cycling back into the pool.
The will be a stamped or labeled word on the base of the filter close to the port the will be your waste port.
There may be a part broken inside the filter allowing waste to bypass and circulate back into the pool. You should clean the filter then inspect for cracks, rips or other damage.
Set your filter to Backwash or Waste, but don't leave it. Empty out what you do not want and return filter to Filtration