Some lessons are best learned by experience.
A few weeks ago I notice sudden drop in water rate to brush head from vanmount.
I put a few questions on here. Trouble is if you don't know the problem, you don't ask the right questions.
I checked the little filter membrane in the pump, sure enough, full of swarf and crud! Cleaned it out, flow improved but not much. Had some time last weekend so checked a few connectors to see if the system was drawing air somewhere...No, all hozelock connectors sound and working well, then I had a brainwave..Yes! The little dial on my varistream has worn a bit, so when I was setting it to 10 o clock it was really set to about 8 o clock, if you see what I mean. The adjuster has worn a bit and isn't set accurately anymore. So I reset it to 0, and reset it to maximum, it worked! Flow good again! 2 days later...no water at all from brush head! I think the worst, the pump has had it! No, I'm learning to check the obvious.....
The little Y connector to the brush head had a blockage! Swarf was stuck right in the Y bit.
The moral of this story?
All the swarf has gradually worked it's way through my system to the Y piece from the tank. When I bought the tank it had been pre flushed, and I flushed it thoroughly before I set it up, but obviously not enough. It has taken a year for the plastic swarf to work it's way through all the nooks and crannies.
Lesson: Flush your tank really thoroughly before you set it up.
Phew! I'm glad I got that off my chest.