You can plug the return lines and skimmer with the pool full. If you have a separate main drain line you will have to dive the pool or get a diver to plug it. The spa (assuming, since you have jandys) should not be a big deal to drain either into the pool or to waste.

I can't understand why the pool was installed without seperate line shut-off valves, since the equip is downhill?? Can you close the maindrain, then put test plugs in the skimmer and return line?

Thanks cascade. I can plug the skimmers and return lines. It's the two drains the are going to be the real challenge. They are 9 foot down in the deep end.

I agree tigpie. I wish I had master shut-off valves on each line. The pool was built in 1986 and was, overall, done very well. It is about 60,000 gallons with two separate systems (the spa is a completely separate third system). Each of the two pool systems has a 3hp pump, DE filter, backwash tank, chlorinator, supplemental heater, main drain, a skimmer and a return line as well as it's own set of solar tubing integrated into the pool deck. There are a total of 10 2.5" PVC pipes coming out of the pool wall that are reduced down to 2" and the entire pad is plumbed with 2". All the pipe, valves, filters, chlorinators and actuators will be replaced as part of this modernization. I just wish I had 10 shut-off valves on the pool wall to be able to work in peace. I plan to add them as the first step and that's why I posted this question.

Anybody had any success blocking off main drains. If so, how did you do it? Thanks. Tom.

Try placing a plastic tub or bucket over each drain. Hold it in place with a weight such as a plastic gallon jug filled with sand. That should slow or coompletely stop the flow of water from the drains. Then cut the old valves off and install the new ones. You should then be able to turn off the flow with the new valves.

Just sandbag the main drains.