Question...drain water then SLAM

oldguy70

Silver Supporter
Jun 26, 2015
159
Glendale, AZ
Maybe be a dump question here.

I read on a post where someone had used somewhere around 150 gals of bleach to do a SLAM (don't know what % the bleach was).

I suppose not knowing in advance how much you would need doing a SLAM, every situation would be much different, but I wonder why I don't read of anyone doing a water drain of whatever before doing a SLAM.

I estimated my cost of draining 7500 gals of water and my cost would be around $75 which would be about 20 gals of 12.5% bleach.

If I think I would be using well over 20 gals of bleach would I be better off starting with draining some water first?
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,932
San Dimas, CA (LA County)
You must have missed a lot of threads. Many times green pools start with astronomical CYA values, and we do recommend water replacement before the SLAM, simply because shock level at 200 CYA is too high to be practical. Likewise with huge CH numbers.

Vinyl line pools shouldn't be emptied, nor should concrete pool in areas where groundwater is close to the surface. Other people have wells, which brings its own problems, or they live under water restrictions. Each case is different. Even if all the water is replaced, there will still be some residual algae spores in the water that will need killing.

If there's a lot of debris in the bottom, a vacuum to waste is usually the first step. All the leaves and twigs get sucked up and dumped out and are gone. But not everyone has a multiport valve where they can do that.

Why don't you post your current test results, and if it looks like water replacement is a wise choice to lower CH or CYA buildup, we'll tell you.
 

oldguy70

Silver Supporter
Jun 26, 2015
159
Glendale, AZ
You must have missed a lot of threads. Many times green pools start with astronomical CYA values, and we do recommend water replacement before the SLAM, simply because shock level at 200 CYA is too high to be practical. Likewise with huge CH numbers.

Vinyl line pools shouldn't be emptied, nor should concrete pool in areas where groundwater is close to the surface. Other people have wells, which brings its own problems, or they live under water restrictions. Each case is different. Even if all the water is replaced, there will still be some residual algae spores in the water that will need killing.

If there's a lot of debris in the bottom, a vacuum to waste is usually the first step. All the leaves and twigs get sucked up and dumped out and are gone. But not everyone has a multiport valve where they can do that.

Why don't you post your current test results, and if it looks like water replacement is a wise choice to lower CH or CYA buildup, we'll tell you.

Yup, I am sure I have missed a lot of threads, and I did say 'every situation would be different'.

That is why I asked the question, just wanted to soak up as much knowledge as I could. I am learning as I suspect you did at one time and asking questions is sometimes a good way to learn.

Thank you for taking the time to reply.
 
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