Why does my fertiliser injector not work

[Ray]

Originally Posted by Clawhammer

Try placing it as close as possible to the tap if you haven't already.

I believe placing it as far from the tap would be better.

For a venturi to work, the PTap must be significantly greater than the PHose+Feed Lines+Nozzles. If moved to the far end of the hose, because of the flow rate limitation of the feeder lines and nozzles, the PTap and PHose are probably close to the same, so PTap+Hose >> PFeed Lines+Nozzles.