Need Help!- VF5 Coolant problem

[BBQ70]

I am faily new to CNC machining as I got my first VF5 about 10 months ago. I started with a synthetic coolant which worked great except for tapping (lots of broken taps). I switched after 3 months to Rustlick 375R a semi synthetic which seemed to work good untill recently. I am now getting a foamy Thick slug floating in the coolant now. This seems to be more than the normal tramp oil that I would skim off. This slug is so thick that I have to skim it with a fine wire mesh pasta type strainer. It almost appears to be the coolant seperating overnight. Yesterday I had a refractometer reading of 6.5 - 7.0 and now after cleaning the slug today I get a reading of about 3. I have an aquarium bubbler and an oil skimmer (which I can't use due to to much and too thick of slug), but have not gotten a dionizer for the water yet. Any thoughts as to what is happening to the coolant? The only thing I can thick of is posible hard water. I only machine Aluminum either 6061 or castings a356 material.

Thanks, Ron

[Excelmachine]

You might want to check out the Haas CNC magazines online, link here--- http://www.haascnc.com/cncmag/default.asp and refer to 2008 Vol 12, Winter edition and the current edition. They have a series of articles going on talking about coolant problems and how to diagnose and solve them. I hope that might help you.

[metalmansteve]

I had many coolant problems before I switched to Blazer. No problems since.

[BBQ70]

I just had my my water tested and was told I have an avarage of 416 ppm of CA2CO3. They also tried to check a sample of the coolant and said it was off the charts. I am going to try a dionizer first before I switch brands since I assume I will have the same problem with hard water no matter which coolant I am using.

Does anyone know if it is poosible to filter the coolant or do I need to start over?