Quote Originally Posted by Jonathan View Post
There is nothing wrong with that setup as far as I know. I'm using an extremely small pond pump that is probably less than 1l/m. Before I had an 8l/m pump and that was plenty...I would say that overkill is good to be safe, but if you're transferring the heat away fast enough anyway then all a bigger pump achieves is to heat the water up more itself. Pond pumps, such as this one (which is plenty), are also brushless:

http://www.ebay.co.uk/itm/Aquarium-P...#ht_2736wt_905
These spindles don't need much cooling as most of the time we're operating them at nowhere near full power/speed and they are inherently quite efficient so the heat generated is not that great. This means that especially if you use a metal container the natural conduction of heat into the atmosphere is enough to keep it stable as long as you have a reasonable amount of water.
You dont need high flow or pressure just good head height. . . . The thing to watch with these pumps is the Head height, this pump can only pump 1.85mtr max which if like me your using the simple pump in a tank under the machine then it's not quite enough. Even thou they say it will pump 1.85 meters this a max and puts the pump under too much stress if run for long periods. Try to aim for one in the 3mtr range and you wont have any trouble, mine's been going now for 3 yrs with out trouble and it's 2.5mtr head height. I've just bought a spare 24v 3mtr head height off ebay thou because it's starting to struggle so time to retire it to just pumping coolant on my lathe.!!