How I made the ”Side walls” off the aquarium
I started out with a very big block of Expanded polystyren (EPS) (isopor). I divided it in two. Shaped it, with a dull knife and my hands. On top of the one with the waterfall. I made a big hole where I mounted a glass-vase. (As the starting point of the waterfall. I also made holes that I put kitchen glasses inn. ( For the over water plants.) I made shelves and tunnels and so on. I also made a lot of other big holes that I filled with stones (glued inn with silicon.) This to reduce the buoyancy of the Isopor. (To make the construction heavier.)
When I was happy with the shape I covered everything with underwater cement. OBS! MADE SURE THE BOTTOM AND THE SIDE, THAT WAS TO BE SILICONED TO THE BOTTOM AND THE SIDE OF THE AQUARIUM WAS AS CLEAN AND AS BIG AS POSSIBLE. As much contact as possible between FLAT Isopor (EPS) and aquarium glass. Before the cement dried I threw sand in it.
I then applied a coat of 2 component Floor paint/varnish (EPOXY) and threw inn more sand.
Made a few small rocks (out of normal rocks) the same way (Paint/varnish and sand) to put around in the aquarium.
I applied A LOT of silicon in the
aquarium where the constructions was to be mounted.
(Bottom and side, where contact was expected) Carefully lifted it in place (If
not; the construction will scratch your glass and scratches stays for ever.)
Made sure it had good contact with the glass and
then it was done.