Help with system design - 25g

[syncro]

Any suggestions/criticisms/tips/feedback on this new tank and sump design?

25g display tank (glass, low iron, polished edges)

17g sump (glass)

Tank with cabinet and sump


Overflow
The overflow is a bulkhead with overflow box around it to set water level. Here is an example. Similar to gl*******s kits but the overflow is not sealed to the bulkhead. When the return pump fails water will eventually drain down to the level of the bulkhead. The sump can accommodate this drainage. Overflow is removable, adjustable and cleanable. The choice for this overflow is mostly asthetic - small footprint inside and outside the tank and easy to clean. Target flow through sump is around 90gph. Gl*******s claims 300 gph with similar design. Additional flow in display tank with powerhead.

Sump
3 chambers plus ATO reservoir. Bubble trap.

Stand
Existing IKEA stand pictured here.

Questions

• Is the skimmer chamber the right size? Water level will be 9" high. No idea what skimmer I will run. Pictured in the diagram is a Bubble Magus NAC3+ (25g - 80g). Can you design a general skimmer chamber or do you really need to choose a specific model and design around it?
• Is 2g ATO enough? Would like enough water to last 1 week. On my 5g I use 0.25g per week.
• mike31154 suggested a gravity ATO. Make a smaller glass tank that sits on top of the sump? Enough room for plumbing and general room to work?
• Any other suggestions, especially on the sump.

Thanks!