hello everyone,

anyone familiar with a device that can be T-d into the irrigation system main line, to supply liquid fertilizer into the main stream while, sprinklers do what they are doing anyway?

i was using free standing one from sears, a large canister with rotating nozzle, connected to a garden hose, and had that idea - why can't same be done by existing sprinkler system? called my sprinkler guy, he told me that there's a device that can be installed outside the main line, t-d into it, and filled with whatever, so that it is being spread over the lawn by sprinklers. but he does not know what it is.

recommendations? will be appreciated.