I ended up putting a gate valve on every lateral after flushing them out.Lateral #4 which is the furthest out was the worst.I ran a garden hose down each lateral until I had water coming out of #1.By the way the tank was shut off it has a gate valve to the field.I then added the product to each lateral and ran the hose in them as well as mixed some up with water and dumped down each one until water just started to flow out of #1 and closed all valves.It will sit approximately 3 weeks before it is dosed.Should I add another container to the system before it is used again?I purchased 2 because of the age of the system.