Help with new tank plans

[Hydroponicfish]

I am replacing my 45 gal tank with a 90 gal and want to go big. I intend to do a partial hydroponics setup, a planted tank with lotuses, a biological filter, a part time carbon filter a lot of water flow and a 15-20 gal tank all in one system. I have included a diagram, but only had my webcam to scan it with. I intend to keep neon tetras, mollies &c in the 90. Does anyone have tips as to the power of the pump, hardy oygenator plants, what I could keep in the 15 with massive waterflow or anything else? I've never done anything like this before and help would greatly appreciated.
PS the pump runs all the time and the valve dumps some of the water out of the 15 every time it gets to full.

 

[Bert2oo1]

That's a serious set up! Can't wait to see it all set up. I can't put any input in for this as I don't have any experience with sumps or hydroponics but your plan looks like you know what your doing. For a 90gal u are going to want a pump that pushes around 8-10x the volume an hour I'd say

 

[traceyrollin]

Wowsa! I cant offer any advice at all. But brilliant design though. Best wishes.

 

[Fresh2o]

Wow, quite a setup. A few thoughts/questions:
1. Have you considered buying or building a sump and placing it under the 90g? The space under the tank should be more than adequate for a decent sized sump. This would prevent having to drill through the floor and the added expense for a pump that can overcome the head pressure between floors.
2. Instead of that complex drain system, how about drilling 3-4 holes in the 90g and installing bulkhead fittings. This would allow two primary drains for the sump and a third emergency drain (in case the others get partially clogged for some reason). The 15g tank will not be needed in this case.
3. In the biofilter (in this case, the sump), you should consider passing the incoming water through filter socks or other mechanical filtration before it gets to the biofilter section. This would prevent fouling of the biofilter with detritus. Placing the media within mesh bags will make it easier to remove for periodic rinsing. Chemical filtration (carbon) can be placed in this sump as needed.
4. What type of lighting do you plan to use for the lotus?
5. For the bog plants above the 90g, you could place them in a long tank such as a 30g long or a pair of 20g longs or some type of shallow plastic trough.

 

[Hydroponicfish]

Thanks.
I don't really know what I am doing-the only reason why I have this project is because I lost all my fish the 45 gal twice in a year and decided to do something new to change my luck. I have been doing a little research and decide to go big and try something ambitious, after all, I got a huge tank.
I intend to keep the lotuses under full spectrum leds because I want them to bloom. I like the bulkhead idea I'll save my 15 gallon for something else.
I am keeping the sump, pumps, heater and possibly airstone in the basement to keep down the noise, not save space & Chinese 750 gph pumps are cheap on ebay ($30)
I am keeping the plants on top as hydroponics I hope to grow a few vegetables, but I intend to keep them in either a homemade plywood bottom tank so you can see the roots, or a plastic tray.(filled with pebbles)
I will add sponge filters thanks
Does anyone have tips for what type of oxygenators or fish?
I already hope to put in neons as my mother loves them. Is that a bad idea?
any tips are welcome!
here are some pics of the tank I'm replacing. The branches are to keep it from looking too empty