3d background / filter advice

[Jread002]

I have a 125 gallon tank I'm setting up for some of my African cichlids. I bought the universal rocks crystal wall 3d background. It's one of there thinner models, only sticks out 3" Max in some places so there is not much of a gap between back of backgrounds d and back glass. I have a fx6 and a fx4 that I will be running the tubing behind the background and drilling a hole for the inlet so the only thing on the front of the background are the actual intakes. I'm not delivering the background to the tank I will be using clips to hold it. My concern is the water behind the background becoming stagnant. I was thinking of drilling some small holes in spots where I can't see them and since the fluval intakesare able to take in water from all sides I would still some holes behind where the I take is. Hopefully the intake will draw water from behind background and the speratic holes around the background will draw water to the rear of the background. Not sure if this would work. Would love to hear suggestions and if anyone has 3d backgrounds what they did.

Thanks

 

[The Morning]

Water will not stagnant but I do get fairly significant buildup of food and waste behind my background. I occasionally use air line tubing and siphon out behind the wall.

 

[Jread002]

So do you have any extra holes drilled? Are all your intakes on the front of your background? My background goes all the way to the top trim of my tank so water won't be able to spill over the top of the background. The 2 holes that the intake tubes will be going through will be fairly tight fit so there won't be much room for water to move through the only 2 holes I've drilled so far

 

[The Morning]

I do not have any holes. All hardware is in the tank. I actually have two different styles but don’t remember the name assigned by universal rocks. Unless you got the sidecaps I believe you will still get waste behind the wall. I wish I had actually just siliconed the background to my 150. Occasionally I get fry behind that one and it is PITA to get them out.
There is always water movement behind the wall but it is especially evident when doing water changes.

 

[The Morning]

You can see in this picture there is one space where the background is not snug against the back of the tank. I actually have the intakes on the sides of the tank and position the suction cups so the intake pushes the background to the back of the tank.

 

[SantaMonica]

I wouldn't worry about stagnation. Any particles that get back there will be consumed by microbes if your animals can't get to it first.