What setting should my hayward sand filter be when I need to clean secondary leaf screen so I don't have water pouring out of pool?

I used to work in a municipal swimming pool. 325,000 gallons!

It sounds like you have the sand filter on to clean if water is coming out of the waste line. That is called 'back flow'.

Basically, the water from the pool comes into the top of the filter and the muck settles on the top. You need to add Gypsum (Aluminium Sulphate) to the water which is a floculant. This makes organic material form into a layer on top of the sand. The flocculated layer further adds as a filter. You need to regulate the flow of water into the filter as too fast and you force sand into the pool.

When you clean the sand filter, you do a back flow. So by altering valves, you put the water from the pump into the bottom of the filter and the water lifts the muck and dirt off the top of the sand and discharges it to waste. It is important to also regulate the flow as too much will discharge the sand. That happened in our municipal pool and discharged 6 tons of sand in the space of 2 years.

your owners guide is here. Take a look at the pipes, valves and pump and work out where the flow is going to.

http://www.hayward-pool.ca/pdf/manuals/ProSeries-S166T-S166T1575XS-S166T1575XSN2.pdf

http://www.hayward-pool.ca/pdf/manuals/ProSeries-S166T-S166T1575XS-S166T1575XSN2.pdf

put in recirculate position if flow increases then filter problem

go to westport pools.com and see if you can find a picture of it or go to hayward filters..

Do you have a strong flow of water back to pool? If so, perhaps pressure gauge is defective, pool water is relatively clean or particles are too fine to be captured except through multiple turnovers.

did you get sand in vertical tube if so it will take time to get out of line

this usually happens when the gasket inside the dial valve has been compromised and ruined. It allows water to drain out and sometime the sand to go into the pool.
you will need a repair kit for the dial valve and that should solve your problem

US Parts Center

You are using the wrong setting to vacuum. This type of pool filter should be set to "filter" for normal vacuuming or to "waste" for heavy loads. The "rinse" setting makes sure that all of the dirty water is out of your filter after backwashing.

A Hayward S180T sand filter holds 150# of sand. In other words, fill the filter 3/4 full of sand (to the point where the tank starts to round off). Make sure, however, that you fill the tank 1/2 full of water first. This will help to cushion the laterals and prevent them from breaking from the weight of the sand. Make sure to cover the hole in the top of the lateral assembly pipe with a cup or duct tape to prevent sand from going into the pipe. If sand gets into the pipe, it will come out into the pool. Don't forget to remove the cup or tape after adding the sand!

There could be a few things causing these problems. How old is the sand in the filter? Filter sand looses its filtering ability after 3-5 years and needs to be replaced. If the sand needs to be replaced, make sure you get actual pool filter sand. A lot of big box and home improvement stores sell play sand as filter sand. That will cause your pool to stay cloudy and never clear up. If the sand is less that 3-5 years old, you may need to clean it with a liquid filter cleaner that is poured through the skimmer. This works quite well!

Another issue causing the cloudiness and bubbles could be the type of chemicals you are using. I know that shock from big box and home improvement stores cause the water to be cloudy. Algaecides from these stores also cause foaming.

If they are to much for the pump basket you can try filter by-pass. Another thing could be a tool called a leaf master that hooks on your garden hose and sweeps any and all light stuff from pool and collects in a bag big enough to hold it all in one sitting.