By water I presume you mean coolant? How is your coolant actually switched, is it a solenoid valve? If it is you will likely need a relay as the current draw of a solenoid will likely be more than the CSMIO can handle (250mA if I recall)
Not sure what you mean about tool length and switching coolant etc. Coolant is normally switched on by M8 and off by M9, so if thats in your code it will do it.
Hood