Any tricks of the trade for drain / fill with a tarp?

[heugeneo]

Tomorrow I will be swapping out some water. We are on a well so because of metals in the water I will be having at least two 4,000 trucks brought in. Obviously we have a fiberglass pool and the installer and manufacturer stated not to drain water past the skimmer. That gets me down to about 10" below the top edge of the pool. My plan is to drain down, place the tarp on top, and fill with the first truck. Then drain down again to bottom of skimmer and bring the next truck in. If the water guy has time I'll do a third, otherwise just stick with the 8,000. Then pull out the tarp and presto (hopefully). I dug down and got ground water at about 22" so I'm hoping going down 10" won't be a problem. I found a couple threads on the topic, one that was really helpful with pics, but had a few more questions.

Is there any problem filling a fiberglass pool to the top? I do not have concrete coping, just the top edge of fiberglass. The skimmer opening will be blocked off with the tarp.

Are there any trips to using the tarp? It seems pretty straight forward, but I know how that always ends up....I'm assuming as long as no one is doing cannon balls into the water I won't have problems with the tarp going to the bottom of the pool? I got a 60x40 tarp.


Thanks for any advice available!

 

[JasonLion]

I really don't recommend using a tarp. While it is possible, it is fairly difficult to keep control of the tarp and relatively dangerous if anyone falls in. For all the extra effort, you get just a tiny improvement in efficiency.

 

[Patrick_B]

I cannot wrap my mind around how you get much benefit from it. Not in practice anyway.

 

[heugeneo]

It seemed to make sense when I bought it (of course). My thinking was this - the 4000 gallons is roughly 20% of my volume. Also assuming my cya is in the 400 range, it may be lower.

If I drain down and add one truck, that would dilute the water by 20% making the cya level 320. Then drain down, add second truck, dilute again by 20% for cya of 256. If able to do a third truck would take it down to 205.

If I use the tarp and do 40% at once that would dilute the cya from initial of 400 to 240, slightly better than without tarp. However if I can get the third truck in with the tarp that would be 60% and take the cya down 160.

I don't know if that's how it would actually end up working, just what it seems to be. It sounds like the slight improvement by keeping the water separate might not be worth that added hassle of messing with the tarp?

 

[jblizzle]

It sounds like the slight improvement by keeping the water separate might not be worth that added hassle of messing with the tarp?

Exactly. Yes, using it would allow you to lower the CYA slightly more. But with the added expense of the tarp, hassle of trying to keep in it place, and the risk of something going very wrong if someone fell in.