Pool closing confusion

[Osa]

I have read the many posts about pool closing and have not seen this particular issue addressed - unless I've missed something. I have a skimmer box with two ports. One goes to the pump, the other goes to the bottom drain but is not connected in any way to the pump system. When I blew air into it with my shop vac a fine mist of silt floated out but no bubbles came up. When I used a shop vac to suction the water out it seemed that the water was coming up from the bottom drain as the line never emptied. - Could there be a flap in the line to prevent backflow? I've read elsewhere on here that a shop vac is not powerful enough to blow a bottom drain. If that is true should I use a compressor instead? Thanks for any advice you can give. I have got to get this pool done!

Osa
20K
IG
Vinyl
CL

 

[pooladdict]

You want to put 4' of foam rope down that man drain line, then plug it. There is no way to blow it free as the water will just come back up the line the second the air is stopped.

 

[Osa]

Pooladdict, Thanks for the reply. When you say foam rope are you referring to the stuff used to fill airgaps that is about 1" in diameter? Should I just leave that port capped all year?

Thanks in Advance,

Osa

 

[pooladdict]

Yes, the same stuff, the idea is, if the water freezes it can expand inward towards the foam rope and not the outside to crack the fitting.

A lot of pools are closed this way and left closed all year, the only difference is, you have zero flow through your main drain.

 

[Osa]

Thanks pooladdict - are you familiar with the noodles of foam for hot water pipe insulation? Would a small diameter length of that work as well?

Best,

Osa

 

[pooladdict]

Yep, that will work just dandy, the idea is you want to give any possible ice formation something easy to crush, versus your fittings or pipes.