Blowing and then plugging returns while underwater?

[gsxrken]

A friend and I helped each other close our inground gunnite pools last week and I have a concern. He was comfortable with blowing his returns out while they were still underwater, and then reaching down and capping them while the vacuum was still running.
I insisted on pumping out my pool below the jets so I had no concerns.
Do you think he'll be OK, or as a friend should I insist we redo his like mine?

 

[dmanb2b]

Glad to hear everything went OK GSX

I'd recommend him following your advice. Plugs and even valves can easily leak air, but it is his pool...maybe a friendly nudge.

 

[Qwaxalot]

Either way is OK. The real reason to lower the water is to minimize ice damage at the tile and coping.
If the plugs you use leak, it's not going to matter if you lowered the water or not (the water will rise under the cover).

 

[bk406]

I blow mine under water. The fitting on the back of the return is usually a 90 degree ell. That means the pipe generally goes down to the bottom of the pool wall before its starts its horizonal run back to the equipment. If any water gets back down the pipe, its deeper underground anyway and wont freeze. Unless your frost line is deeper than 3 feet or so, its fine.

 

[gsxrken]

Thanks for the replies. Sounds like he will be OK. He was last year, but it was so mild in NY last winter that I don't put faith in just that one fact.

I can also advise not to use an air compressor for blowing your skimmers while trying to catch the Gizmo screw-in plug. The pressure gets too high and the plug can become a projectile!
Vacuum is more flow, less pressure... but the vacuum didn't have enough oomph to bubble up the main drains under 7-1/2 feet of water, so had to use the compressor there.
Saved myself a ton of money and further bonded with my pool. We are one now.