View Full Version : polyquat shelf life

05-18-2007, 04:38 PM
Does anyone know if polyquat degrades significantly over a couple of years? Is it worth buying a gallon at a cheaper price to use over several seasons or is it better to buy what I need for this season only?



05-23-2007, 09:38 AM
Sorry, I can't help with the answer but it seemed like you, unlike myself, know what Polyquat is. One of the moderators mentioned that it was the only algacide they recommended but I can't find it. Is polyquat 60 a componant of most algacide or are there specific brand names. Any help would be appreciated

05-23-2007, 11:40 AM
I believe that polyquat 60 should remain in good condition for a while. Store it in a cool location out of the sun. Heat and sunlight are what degrade most pools chemicals, sometimes slowly, somtimes (as with chlorine), fast.

polyquat 60 is the recommeneded algaecide. It is not a brand name but the common name of the active ingredient. Look on the label for poly [oxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene dichloride] and check out this page on PoolSolutions for more info:

Also, HTH is no longer selling polyquat so you will not find the product that is illustrated in the picture on that page!

05-23-2007, 11:53 AM
Timely thread for me,

I just bought a gallon of 60 percent from Leslies. I won't use it all this season, so I was curious about this as well.

I couldn't resist buying a whole gallon, it was a huge savings (came out to about $13/quart. It's still on sale on their website if you need to pick some up - I think instore will usually honor the website prices.

chem geek
05-23-2007, 06:26 PM
The official word I just got from Buckman Laboratories that make the PolyQuat sold in the U.S. is as follows:

PolyQuat is a biocide that is registered with the USEPA; and, as such, it will have a specific guaranteed shelf life. The shelf life (which may or may not be printed on the label) is one year. In general, registered biocides are assumed to have a one-year shelf life unless the label states otherwise. While the compound itself is very stable and is not expected to decompose upon storage, we cannot guarantee it beyond the stated one-year shelf life (due to legal and regulatory considerations).

In other words, it is "guaranteed" to last one year, but it's a stable compound so would presumably last longer. How long -- well, who knows. And be sure to check the label to see if it states otherwise (i.e. a shorter shelf-life).


05-24-2007, 02:43 AM
Is that one year from date of manufacture or one year after openeing since shelf life is often defined as from one of these events? If it is one year after date of manufacture than it is possible to purchase a product that has expired because it is not uncommom for products to sit ih supplier's warehouses for quite a while before making it into a store's inventory and the product might also sit in a retails store's warehouse before making it onto the shelf (not to mention how long it might sit on the shelf before it is sold!)

chem geek
05-24-2007, 12:18 PM
If you read between the lines, the PolyQuat is very stable and not expected to degrade. It should probably last several, if not many, years (especially if kept in cool conditions that are not freezing). The "guarantee" is based on purchase date (there is a presumption of turnover and the "one year" number is a default, not something determined explicitly for this product) but in practice there shouldn't ever be a need for this. However, I doubt if anyone in the history of this pesticide has ever returned it to a store because it "went bad".


05-24-2007, 12:59 PM

05-29-2007, 10:05 AM
Thanks guys.

I emailed Applied Biochemists (makers or Pooltrine products) as I used that brand last year and have been very happy with it. They said two years but didn't specify if that meant once it was opened or from the date it was made. Either way, I'm not concerned - I just wanted to make sure it would be good for awhile and that seems to be the case.


05-29-2007, 12:44 PM
I just keep it in a cool basement and it seems to last for years...the batch I have is several years old--it was on sale. I use a full quart at the end of the season to close.