Do you have an air compressor? I bought a rubber mallet for like 3 or 4 bucks. I drilled a hole through the middle of it. Make the hole big enough to get the end of a blow gun attachment for an air compressor. The rubber part of the mallet makes a pretty good seal on the end of the pool lines. Let the pressure build up in the compressor, make a good seal with the mallet and blow the water out of your lines. I've been doing this for about 12 years. It works great.

As far the blower or shop vac, I don't know if it will be strong enough. It might work, good luck.