Hi Tim,

Applying absolutely NO aviation-specific knowledge here, but your best bet is
probably to buy plumbing antifreeze. Available at Canadian Tire (if in Canada)
, or (I assume) at Walmart if in the U.S.

If all else fails, you can buy it at ANY trailer parts / supply store.

I assume winterization is the same for any form of water tank (perhaps a bad
assumption), but you only need to use the winterizing fluid to displace /
dilute the water, you don't need to fill the tank with winterizing fluid (in
fact, air probably handles temperature change better than the best form of
antifreeze).

The main goal is to use the antifreeze to displace any water left at the
bottom of the tanks, or iany fluid that is vapour locked in the tubes / dump
valves. As such, put in enough fluid to ensure coverage, then allow it to
flush through any tubing / valves that may have water in them.

You should be able to do everything you need with a couple of 1-gallon jugs
(windshield washer size), i.e. for about $6-10 dollars spent.

Hope this helps,
Graham
Tim Taylor wrote:
As the cold weather is appraoching in the northern hemisphere what
antifreeze can be used safely in integral water ballast tanks such as
in my Ventus? Also where do you buy it at a reasonable price?

I am guessing the maximum use would be about 25% v/v at any time. I
think I could often use 2gal Ethanol to 13gal of water in each wing.

Methanol
Ethanol
Isopropyl alcohol
Propylene glycol
Others?

Thanks,

Tim