Beautiful build and great craftmanship

However, having the pumps rest on the acrylic shelves is a bad idea for two reasons:

1) Vibrations. Pumps vibrate a lot and although the acrylic will somewhat dampen vibrations they'll still propagate to the aluminium walls and I doubt you'll be happy with the result. So you may want to decouple them.

2) Heat. These pumps can get pretty hot, and counter-intuitively they get hotter with less restriction in the loop. They risk overheating if rested on the shelves.

You may get away with some venting holes where the pumps are resting as it won't show. Getting rid invisibly of the vibrations will be more challenging, maybe have the pumps rest on rubber or silicon

Unfortunately since the pumps need to be primed to run, it won't be easy to test the best (i.g. most silent) decoupling method.

Anyway good luck and again congratulations on a beautiful build.