low toxicity with anticorrosion/anti fungal additives
Coolit coolant is ''25% propylene glycol (low-tox antifreeze) and 75% distilled water ''.
You have 3 options:-
1) You can use commercial/automotive antifreeze as a source of propylene glycol and do the mixing yourself.
2) Coolit now produces watercooling products for Corsair and that is why they use the same coolant. Corsair does not seem to sell the coolant directly to consumer. But Corsair appears to use Sierra Green which you may try to buy.
3) If you wish, you can also use Zalman's ZM-G200. Zalman recommends using a mixing ratio of 20:80 (just similar to Coolit's practice).