“Pool winterizing antifreeze has gotten pricey. Is there a way I can make my own antifreeze for my pool lines? My contractor and I put the main lines below the frost line as a preventative measure.” -Kurt
At anywhere from $15 to $30 per gallon, pool antifreeze can certainly get pricey, especially if you have long supply lines.
Pool antifreeze is generally a propylene glycol solution, sometimes mixed with alcohol or other additives and sometimes just diluted with water. Propylene glycol can be purchased in bulk – one source I found was The Chemistry Store. If you decide to make your own solution, I would recommend getting some sound advice from a chemist or pool specialist regarding the correct proportions and type of water (distilled, etc.) that should be used, and also in proper storage and disposal of propylene glycol.
Pool line antifreeze will eventually end up in your pool water. Don’t try to cut corners by substituting auto antifreeze or any product with ethylene glycol – even at low concentrations, the ethylene glycol reacts with pool chlorine to form toxic chlorinated hydrocarbons in the water.