I hope I can answer all your questions
1) How often do I need to re-fill the water tank where the coolant goes in and where do I get replacemant fulid from or coolant[/b]
* In my case I would say in a month, this depends on how long do you intend to run your computer. If you keep on removing the hose once in a while, it will also lessen the coolant.
Note: Be sure to have a tissue or a piece of clothing to cover the hose when you disconnect it from aquagate.
* Where did you get your unit? Tell them to order CM coolant.
2) Is it best to put the unit inside or outside my system?
* I bought the aquagate for it's innovative purposes. It is the only liquid cooling that can fit in your drive bay.
If your case has a front panel like the wavemaster. Its up to you.
3) Is it reconmended to do a leak test for 24hrs before installing it ?
* Not really, you can test them for 2-3 hours. Be sure to install everyting including the PCI card before you can test them.
4) Is there any planned optional extras for this unit?
* they said optional feature for the Video card but i'm yet not sure.
5) Can you add uv dye to the water tank?
* CM would not recommend. The color of the coolant will fade in a month.