How deep is the sewer line?
About 18 inches below the sprinkler system, unfortunately.
bought one of the electric eels off ebay for 50 bucks plus 68 shipping get 300 bucks for clearing a drain
That's a possibility. It never fails that the clog starts on a weekend, usually during the holidays. Drain Kings push enough through the roots that we can use the toilets for a couple more days, but don't do anything to get rid of the roots themselves.
I don't know but Copper Sulfate Pentahydrate does. Also know as bluestone.
We've been dumping it in every few months, and thinking about just buying it in bulk, but it doesn't seem to be keeping up. OTOH, I cleaned out the shower that we don't use very often with something over a quart of muriatic acid, and heard the sewer line suddenly let go as I was rinsing. Don't know if it actually dealt with the roots in a matter of minutes, or just dissolved everything that was caught in them, but it's something to keep in mind.
Sounds like you need to put a check valve on your sewer line going out of your house.
Gee, there's a thought. IMO, it should be standard on any waste system, for the obvious reasons. Last I looked, 4" check valves weren't even that expensive. OTOH, it doesn't really help with the situation where nothing can go out, and backs up from inside.
This is what you need
http://www.turnasure.com/images/p-pipeflange-1.jpg
Don't tempt me; one of the clients makes that type of flange.