[Herbertkabi]

When to speak about milling machine then I use the same coolant mix for Spindle as for milling by the same pump and at the same time.
I do use special coolant oil mixed with tap water.

*Used coolant, when milling process, goes to Collector tank (plastic tub) through robust filter (cheesecloth) left all chips and grindings -> *Fine Filter (common home RL-SX washable polyester filter - 50 microns) -> *Coolant Tank 20L -> *Coolant Pump 12V -> *Spindle -> *Coolant nozzle.

Filtered clean coolant goes at first to Spindle and then from spindle to coolant Nozzle(s)
I have second pump as well - for to wash and clean machine and milled parts with simple gun. This is also very good, machine keeped clean, dirt and chips washed away in to collector tank.
Fine filter I do wash once in month when milling aluminium, when to mill these expensive beige color prototyping and moulding materials, then even every day ... it takes 5...10 minutes to wash. Congregated metal chips from first tank I take away when it is full (ca 40L), cheesecloth need to be washed-cleaned only when mentioned prototyping and moulding materials have been hardly milled
Of course this is not for Lasers but for me and for my mill this system is the best solution, using near two years. Coolant never went to pong, perhaps this is because I use only special oils for coolant mix, or fine filter helps

Cheers,
Herbert

[zoefie]

Hi I use clear water with a little anti-freeze in it.
I noticed that after a couple of months the algae sometimes started to slime up the water.

I have found the simplest yet 100% effective method to solve this problem, There is just one thing algae don't survive and that's UV light.

I have a koi pond and am using uv light to prevent algae there so i installed a small 11 watt UV algae killer in the return waterline since then i have seen no algae or other slimy stuff in the water, it's as clear as the day i filled it up.

They sell those uv-lights for less then $75 in the pond shops

Happy lasering!!