Blowing Out Lines..Shop Vac Not Working

I have a 6 hp shop vac and it seems to be under powered for the far skimmer and return, which is about 40-50ft from where I'm blowing. The skimmer I can deal with but does take some time.

I have to put it on and take it off to get the water to bubble then when that finally stops working I use a turkey baster to get the water out when it comes high enough. After a ton of turkey sucking it finally can push the rest through.

Now the returns I have 3 and the first 2 bubble like crazy and I cap them but the 3rd one(50ft) never gets any air coming out at all and for the past few years have just capped it and put antifreeze in the line.

I want to get air out of this line and maybe make the far skimmer a little less work so I was wondering my options.

Right now I just hold or tape the shop vac into place depending on what line. Would a bigger shop vac work or do I need to look at compressors? Not looking to spend to much but did always want a compressor for around the house. Which attachments would I need for somewhat of a seal with a compressor? Not sure how a hose off a compressor would help without some sort of seal. Any help would be great.

Compressors aren't all the same. They have two main features: Pressure and volume. Some apps, like nail guns, require lots of pressure but little volume. Others, like tire inflation, require little pressure but more volume. Others, like blowing out sprinkler lines, require LOTS of volume and more pressure than a shop vac can deliver. I have tried to blow out my solar panels with my 20 gal compressor...fail. My shop vac works better.

I don't know what size compressor will work, though.

I would think that you would need to develop enough pressure with either a shop vac or compressor to overcome the weight of the water column. If you can do that, the water will move. Are you certain that the line isn't blocked? Try pushing from the other direction.

Check out www.leaktools.com. They have air induction fittings in various sizes that you can hook to a compressor.