So an interesting experiment with hardware store silicone sealers....these two were clear versions by GE
Easy to handle and spread around, very acetic acid stinky so do it well ventilated area.
Both were labelled as clear and after 3 hrs were dry to touch and perfectly able to see though to the base.
Paintability is interesting as my Citadel water base acrylics do not really hold (LHS in pic). Tamiya acrylics (RHS) did better but still not full on coverage. There are paintable clear caulking silicones (GE Silicone II) if you need to surface paint.

There are some great videos on cheap silicone water effects....you don't need to buy expensive ones
Gollum and some rocks are now crazy-glued on and some final accent paint/shading done on the base

Silicone in the morning