Thank you all for your nice comments! I'll try to answer some of the questions you have asked. First of all the question from Diana. The plumbing that is incorporated into the background are not used for intakes. My overflow box explained:
The intake to my sump is done by using an overflow box. I have a combination of surface skimmer and bottom skimmer. As you can see by this picture.
The water flows over the comb, meaning i won't have that oily surface.
The water in my overflow box is lower (B) then in my aquarium, and this is CRUCIAL for the bottom intake to work. In my overflow box there are 2 pipes. One of them is the emergency (C) drain, attached to my sewer. This way, the tank can never overflow. The other one is the overflow to my sump. This is regulated using a ball-valve so it lets through just as much water as the amount of water that is pumped into my aquarium. This means that i have a 100% silenced overflow. On top of this are off course from those white filter watts (how do you call them in English) to filter out the biggest dirt.
Here you see the bottom skimmer. Off course this is not exactly as it will eventually look, but my drawing skills are not THAT good
Because the water level in my overflow box is lower then in my tank, the water "puts pressure" on the bottom skimmer and it pumps out (e.g. sucks) water into my overflow box. This also works in my current setup, so i am not worried it won't in my new Returns
So i have incorporated my returns (from the sump) in my background, allowing me to keep every aspect of PVC and electronics out of the water. There are 4 returns in total, which are numbered below.
A) return in front of the glass
B) return in front of the glass
C) return of co2 injected water
I decided to "split" my returns into 1 and 2, to prevent dead water spots on the side of "2", and to decrease the chance of blue algue. Also this allows for more circulation which means off course more nutrients for the plants to pick up. Also the fish like this more.
One of the problems of incorporating the returns in the background of the aquarium, is off course the power outage. When the power goes "out", i would have a siphon, draining almost 2/3 of my aquarium. To circumvent this, i've put a non-return value of size 32mm (1 1/4") which will "stop" the water. Although this has a very high resistance before it "opens" (= less pump power) it is the most safe way to work. The planning
@guaiac_boy: yes it has been a lot of carefull planing. As i might have said, it was the result of spending quite some money, and i came home twice with water on the floor (snail was caught in overflow). All these issues are addressed now, so if this doesn't work i'll stop with the aquarium hobby
As for my lightning, at first i wanted to go with 4x36w and 2x54w. Meaning 6 fixtures with a total light capacity of 248w, meaning 2w/gallon if everything is on. But.. Yesterday i want to a fellow hobbyist from the Netherlands, and he convinced me to go to T5 all the way, so i might end up with 7(!!) 54w lamps, totaling 378w (3.02w/gallon) If that doesn't give me algae (ehh nice plants) then i don't know..
As for the hood (which i will explain in detail later) i am going for a so called "sandwich hood'. This hood originally came from "Willem v Wezel" as you might or might not know. He is famous for being excellent at dutch planted aquariums and some of his pictures have been posted a few times on this forum.
The hood itself will not be any higher then 2-3", this is possible since i have put my stabilizers relatively low in my tank. The inside of the hood will be 3mm plywood, on which the fixtures are mounted. The plywood is grounded white and then painted with outdoor quality white high gloss paint. Here in the Netherlands some of us has measured the intensity of the lights with and without reflectors, and the conclusion was that a white hood was much and much better then reflectors.
@jack; Although canister filters are also a very good choice, i must admit that i am one of the very few to use a sump for a planted tank. The reason for this is that i am not sure if i always keep a planted tank. I might move to Peru altums or maybe discus in the future, and then i would need as much filtration as i could possibly fit under my stand