Anyone used fake rocks for hiding pumps/stuff?

[Koi]

has anyone used homemade/purchased fake rocks to hide pumps and filters and stuff like that? I have been making fake rock out of hypertufa? cement mixes to hide my pump.
Its cool because I can custom fit it.. but am having issues getting the mix right - and ii dont want a 100 pound 'rock'.
Thanks
Jason

 

[DoDad]

I made all of mine using sand mix and fire clay.
https://www.gardenpondforum.com/my-pond-t3319.html