Newb Backwashing Question


New member
May 26, 2021
This is my first time posting so to easy on me. We bought a house in southern Indiana last year that has a 23000 gallon L shape in ground pool. When we took possession- it was already October and the previous owner left us to close.

anyways - the leaves were dropping and I was renovating the house so the pool got full of leaves and clogged the skimmers and burnt the pump up - it was an old 1 speed pump anyways but dumb mistake on my part. Fast forward we had a Hayward super pump vs installed and had it professionally closed. The pump connects to a Hayward valve then to a Hayward s200 sand filter. Idk if it matters but I have 2 skimmers, a bottom drain snd then 4 jets.

We have a mesh cover so the pool got nasty (dark green) over the off season so we have been shocking and running the pump 24/7 to clear it up and we’re getting very close.

that said - I’ve been trying to backwash daily given how nasty the water is. So I shut the pump off, then go to turn my valve to backwash then open my backwashing drain valve (not sure the proper term for this). But when I turn the valve - I lose prime on my pump and then I have to wait for the 8 minute prime sequence everytime I backwash.

so my question is - is this normal? Should I let the prime sequence finish THEN let it run for a few minutes normally? Or is it still backwashing even in the prime sequence? I’ve been seeing a lot of junk flowing through the sight bubble when priming and usually it’s clear before the prime sequence is even close to done. So I’ve been calling that good, moving to a short rinse then putting it back on filter.

I honestly don’t know the physics behind priming to know if it’s still backwashing then.

hopefully I explained that well enough. I’d be happy to add images if needed!

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: You shouldn't lose prime when changing selections. But let's recap some filter basics:
- Before ANY multiport valve (MPV) changes, always turn pump OFF
- To backwash, pump is off then move handle to BACKWASH; monitor backwash until clear; then pump back to OFF
- Switch handle to RINSE and rinse until sight glass is clear, then give it another 30 seconds to one minute; then pump back to OFF
- Switch handle back to FILTER

If you are losing prime, you may have a suction side air leak - air getting sucked into the system from the skimmer to the pump. First place to check ... under the clear lid. Make sure the O-ring under the lid has a good amount of pool silicone lube. Let's start there and we can help more. Post back with your updates.
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