Question
when i turn on the station for the backyard i can see water bubbling up from the valve box. i dug around the valve and turned on the station and the water is gushing from a pvc pipe connected to the valve. this pipe has a cap at the end that looks like it could be taken off, or tightened. it feels like there is a hole at the end of the cap. it only leaks when the station runs. this is not a small leak, i'm talking 5 gall. water gushing when the zone runs 5 min. it floods the flowerbed.  help

Answer
You need to thouroughly expose the leak by digging and clearing all the soil around it, so you can see exactly what the problem is.  It may be as simple as tightening the loose fitting, but it is seldom that simple.  Once you have the pipe exposed and identify the problem, you can make the repair.  You may have to cut out the bad area, purchase new replacement parts, and glue them in.