Setting up my first discus fish room!

Hello everyone, I am new to this forum. Right now I am in the process of building my fish room. I have planned to have 8 to 9 tanks. The first question that I have is what size of breeding tanks should I use. I am deciding between 20H and 29. No matter which one that I decide to use, I will have 3 breeding tanks. The other sizes will be 3 50 gallons and 2 or 3 75 gallons. This setup will have an automatic water changing system so all the tanks will be drilled. The next question is, what form of the auto water change system worked best for those of you who have it? Another question is what type of filter should I use, sponge or external? Responses are greatly appreciated and I will be updating everyone with pictures and info on the build as I go on.
-JAKE-

I think most people use 20H, though personally I like having a little more room and have 29s. Mostly personally choice and what will fit best in your fishroom. I started with all external filtration, moved to using both external and sponges, and today I've got nothing but sponges going. There are a few of use here on SD from Wisconsin, though it seems like the number has about doubled recently. Some really good people around, hope you enjoy SD, welcome.

check here http://jehmco.com/ they got a bunch of what ur looking for.maybe have them design something for u

With 20H I can get up to 410 gallons of tanks in my fish room. With 29 I get 387 gallons of tanks. So it is not a huge difference but it does change the look of my room. Thanks for the website too, that's is very helpful and has a lot of stuff that I still need to get.

what type of RO unit should i get?

I got a typhoon III extreme made by air water and ice. It's a 150 gpd unit. It's not so much about how much it will make in a day, as it is how fast it will make what I want.