Doughball killers

[Leann ull]

I've seen their crusher it's an expensive piece of kit for commercial breweries and not sure that's your issue tbh.
What water to grain ratio did you use or what was grain weight and how much water did you add?
Under letting doesn't cause stuck sparges, you still need to give it a good stir after filling from the bottom as well though

[neoanto]

Yea I gave it a good stir after I filled it.
I used a medium thickness from beersmith so for 4kg of grain I had 13.5ltrs for the mash.