So you've decided to get a water cooled spindle, either our ATC System or our Traditional Spindle System. 

There are 2 basic options for a coolant delivery system, a pump or a chiller. 

The pump is a submergable pump which will force the coolant through the tubes to the spindle, and then after it gets to the spindle, the motor will force the coolant back into the return line. It makes no difference which one is feed and which is return, and the feed line is the one hooked up to the pump, and the return line just drops off into the bucket. You will be required to provide your own bucket, and coolant. The water goes out the bucket to the the pump, to the line, to the motor, and returns a little warmer than it left because of Thermal dynamics. Pro tip, also get a lid, and use gromets to reseal the holes in said lid to accommodate the hoses, and wires coming in and out of the bucket. 

The other option is a chiller. This is a CW3000 chiller which is a passively cooling chiller. The reason its passively cooling is that it is a fan that blows ambient air over coils that "cool" the coolant. There is no refrigerant involved at all, and it doesn't get "cold" but it keeps it from getting hot. Our chillers should not be used for a laser, and a CW5000 (what lasers need at a minimum) should have as high of a temperature as possible. 

After the Pump/Chiller debate is settled, next comes the hoses. The Superthane Ether hose is what we recommend as both the Silicone and Polyurethane are on opposite sides of the spectrum with being too flimsy, or too stiff. The superthane is the middle spot... 

Now which coolant?

There are many suitable options out there. The important thing is that it lowers the freezing temperature, and raises the boiling point. Popular options include:

Windshield Wiper fluid 

Antifreeze Concentrate and distilled water (1:3 ratio)

50/50 Coolant and distilled water (1:1)

RV Antifreeze

Straight Distilled Water

Regardless of which one you choose, you should have a plan for replacement, and it is recommended to do that annually.  

Really the worst option is water from the tap as it likely contains contaminants, as those contaminants would build up in your spindle, and reduce efficiency. I'm sure there are other options that are available and suitable for use, however the above listed ones are the most popular, and asking for something else will likely result in the above listed options.