Without going into too much detail; I tweaked my pump, it wasn't great and I've tried alsorts and dont know how to get it back to normal.

I've tweaked everything you can without taking the lid off the thingy (4 screws and turn a diaphragm).

Any idea how I get it somewhere near standard?

Having just done mine in a 200.
Return to sender!
Pay the money and get it set up by someone who knows - it isn't a fortune and it buys a lot of piece of mind