This is the pump:

https://www.amazon.com/gp/product/B07Q6T7HJ2/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I think I paid $68 for it at the time. It's been jerry-rigged to the Grainfather and has worked since I installed it just fine.

I used this to be able to plug it directly into the controller without modifying the plug or wires:

https://www.amazon.com/gp/product/B0787Z8HKJ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1