Liquid Solar Cover

Tfrzb

New member
Jun 27, 2020
3
Phoenix AZ
I read on in an old discussion about making a homemade liquid cover by mixing Stearyl Alcohol with Isopropyl Alcohol. I did a little research and found the Stearyl to be used in cosmetics and in evaporation suppressing products like the products at pool stores. I have tried one of the retail products in the past and thought it worked to keep the pool temperature stable or stabler.
Earlier this year I bought some Stearyl Alcohol (came in a bag, small white flaky pieces) online and tried to mix it with Isopropyl alcohol. I tried and tried and tried to get the flaky pieces to dissolve but never really got it to. The old posting which I couldn't find this morning had a description of the mixture like 6 oz of Isopropyl and a 1/2 ounce of the dry stearyl. I'm not sure what type of dry measurement that meant so I used about a tablespoon. I put the liquid in a jar and added the dry to it. It did get a little like a liquidy jell, nothing like the retail product I'd used before. I took a chance and poured a couple of ounces in and saw that the stearyl specs were visible, much smaller than the flakes it started as. I think it worked but it was visible on the surface of the water.
So my question is does anyone know how to mix the Stearyl and Isopropyl into a clear liquid like the retail products?
Thanks
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,063
Tucson, AZ
Both stearyl and cetyl alcohol (fatty acids) are sparingly soluble in lower molecular weight alcohols (ethanol or propanol). Most commercial formulations of “liquid pool covers” use propylene glycol as the solvent and dispersant for the fatty acids. Cetyl alcohol is more soluble than stearyl alcohol.

You can try ethyl alcohol but I don’t think you’ll see any better results.
 

Tfrzb

New member
Jun 27, 2020
3
Phoenix AZ
Thanks for the reply to my question. I just took a quick look for propylene glycol and it comes up available as a food grade additive which would lead me to think it would be safe to use in a pool. It looks like it cost around $20 for a gallon which would still be a fraction of the cost of the retail products. Just to be clear when you say they use "propylene glycol as the solvent and dispersant " does that mean it would do what I'm looking for a simple two part solution of safe chemicals to make a DYI liquid pool cover. You go to mention ethyl but say it probably wouldn't do any better, it also appears to be available and safe at the diluted amount I would use.
I swam in April when I tried my first experiment. We had a very warm week and I think it made a difference retaining the heat. We dont mind the warmer pool in the summer and would welcome an extra couple of weeks at the beginning and end of the season.
Really appreciate the feedback, I'm surprised there isn't more information about this seemingly simple DYI type of thing.
 

JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
17,063
Tucson, AZ
Sorry, I have never tried to do what you are planning so I have no advice on what ratios are required. You'll just have to experiment on your own.

Honestly, I wouldn't waste my time with the liquid solar cover stuff as it only has a marginal effect at best on heat retention but it can cause all sorts of problems with chlorine demand and leaving behind organic residues. Stearate's are not something you want to get in your pool water as they can react with high calcium levels and leave behind a very thick "soap scum" that is difficult to remove.
 

Tfrzb

New member
Jun 27, 2020
3
Phoenix AZ
Thank you for the feedback and I appreciate your opinion about the possible side effects of soap scum.
I am planning on changing the water after the season. I've lived here for 10 years now and changed the water once 2 years ago. For most of those ten years I've taken a sample of water to one location, it was an NPS now its a Leslie Pro store. Hit or miss mostly now on the experience behind the counter. For most of the years I followed the advice and added what was recommended. When it was suggested to changed the water I did. On the first water sample after replacing the water it was recommended that I change the water because of the high mineral and solid content. I'm not sure I saved the analysis so my description my be a little simple and not exact.
Since I'm changing the water and doing other maintenance work this off season I may experiment with my DIY liquid solar cover. I'm gonna keep looking and trying