Mostly possible but it only has one RGB LED connection, even with this I am not sure if a single LT will handle 2 LED's on the same connector but this is something I will be trying in the future as well.

It will handle your fans although you will have to connect more than one fan to each header (use 3 headers one for each group) but this is how most people do it. A Single unit will also handle 2 flow meters but you will lose a fan header for one of them (will still have enough fan headers though). No issue with the temp sensors on one unit.

I assume you want the LED to reflect the temp and change colour accordingly in which case as you will have 2 loops and so different temps you will most definatley need 2 5LT's.

I have read elsewhere in this forum that attaching 2 RGB LEDs to the same connector will damage the aquaero, so I would suggest against that. There is a PCB someone has designed as well which is somewhere on this forum allowing 2 RGB LEDs to be connected to the one header but I have never tested it.

One aquaero will handle everything else. You could also add a few Poweradjust units to help with extra fan headers. The Poweradjust also includes an additional temp sensor and header for flowmeter and they can be "daisy-chained" together and linked to the Aquaero for monitoring.

Are you planning to control your pumps from the Aquaero as well? With so many fans attached to the same header on the aquaero it may generate quite a bit of heat on the fan amps so you may need to consider getting the passive heatsink or even the waterblock for the aquaero to keep that under control or it will overheat and set everything to run at 100% to protect itself, which sort of defeats the purpose of having a micro-processor fan controller.

I personally run 2 LTs on 2 loops just to make it simpler for myself and to have the 2 RGB LEDs, but it isn't absolutely necessary. Have fun with your custom build!

Each aquaero will have its own tab in the software so you can easily switch forth and back between them.

Each aquaero will show up as a seperate device in aquasuite and you will have to configure each of them seperately with their own profiles and they will run independently. I have not encountered any problem with the software monitoring two devices.

I am wondering if you can connect the aquaeros via the aquabus to read the sensors attached to the other unit? Does anyone know if this is possible? Will it damage the device? Shoggy?

*Never mind answering that, I found my answer in the user manual ...

That is not possible at the moment. We plan to offer an alternative firmware for the aquaero so you can connect one as a slave device to another aquaero. This way you can use the four main channels, the two PWM channels and six temperature sensors. All other in- and outputs can not be accessed to the main aquaero.