Here’s how to install your background to the aquarium
You have the choice between foil backgrounds and décor backgrounds which are attached at the inside of the aquarium. The foil backgrounds need to be glued from the outside, best with a special background adhesive ( JBL FIXOL ) and can be removed at any time. The background adhesive has the effect that the foil avoids reflections in the glass and appears more vivid and colour-intensive. The simplest method is to lay the aquarium on its front pane so that the back pane is on top. Then apply the background adhesive to the outside of the rear pane, position the foil on it and smooth with the enclosed scraper or a sponge the air bubbles. An adhesive tape and a fabric tape around the foil prevents it from slipping.
For decor backgrounds INSIDE the aquarium it is important that the water volume BEHIND the background doesn’t “foul” but does get moved. A small pump is sufficient for that.