Originally Posted by Italy592
wait theres ni way around doing with the water in there or substrate ??
Well, you're definitely not going to secure the background to the tank ,using silicone, unless its dry. Some stong magnets could do the trick but foam board is super buoyant.
I would strongly suggest watching some videos on youtube. There are a lot of them. Just search DIY background.
It takes these guys quite a bit of time and they have empty tanks that they can lie down flat, in the middle of a room.
Soaking the finished cement background is also an issue unless you have a container that can hold.water, that is also as tall as your aquarium. This is another instance where it really helps to be doing this to a new, empty, tank
I'm sure all of these problems can be solved, but you're definitely gonna want to work out the securing and soaking issues before beginning.