a really tricky one:- dirty water pumped into my pool NOT after backwash or filtering

[scratchingheadgazzy]

Hi guys and thanks in advance for any advice on this one. i am getting dirty water pumped back into my pool for a few seconds when the pump has been off for anywhere over an hour and then comes back on. i checked other threads and everyone suggests that its about rinsing after backwashing or a damaged lateral. i have backwashed and rinsed i have pulled the filter apart (twice) and there is nothing wrong with the laterals but sure as anything each time the pump comes on i get a cloud of light brown water- and my pool is always cloudy because of this. sure i shut the pool down let it settle and vacuum to waste and for that moment everythings great... UNTIL!

it is a 50 000 litre pool with a 2.5hp pump and a 21" filter running 100kg zeolite. i backwash according the the gauge and have a polaris 360 pool cleaner. the balance is spot on the cya salt and fc is right where it needs to be. in short my pool would be the best in the street but for this issue. does anyone have any ideas? at this point ill try anything

cheers

 

[zea3]

Welcome to TFP! Have you checked the spider gasket on the multi-port valve? The only other thing I can think of is that 2.5 hp may be too much pump for the size of your filter. Has it always done this?

 

[carveitup]

Does it come out of all the returns or only one? I imagine a cracked plumbing line could do this if the ground is we out the water table is high. Are you losing any water?