Algaecide Expiration?

[gkruske]

Does algaecide expire? Reason I ask is that I used a quart of it last year when closing. Bought one of those corny overpriced winterizing kits, not knowing any better.

Previous owners left a bunch of unused chemicals, most of which didn't apply anymore, so I pitched them. I have one gallon of algaecide. I see no expiration on it, like I did on the rest of the chemicals. Does this stuff go bad? I'm guessing it's probably 3 years old, but still unopened.

Greg

 

[Bama Rambler]

I have no idea if algaecide expires , never used the stuff but, you'll have better luck getting an answer if you'll post the ingredients and the brand name.

 

[gkruske]

AquaChem

40% alkyl dimethyl benzyl ammonium chloride.
60% inert.

I'm thinking this might not be strong enough on the closing side, but better for the opening side of things. I remember using 60% last year.

 

[chem geek]

The answer to shelf life for PolyQuat is in this post. The product you are using is a linear quat which is less expensive but can foam. It, too, probably has a fairly long shelf life, though three years might be pushing it.

 

[gkruske]

Cool. So, here's this. I know that there is a recent post about 60% strength, but will 40% be okay to use? I plan on closing Saturday, and would rather not go back to the pool store.

Greg

 

[chem geek]

The strength is not relevant except for the economics. You just use more of a lower strength product. In the case of your linear quat, just use the recommended amount for closing which should be higher (about double or triple) the maintenance amount they normally recommend.

 

[gkruske]

Awesome. Also, just finished reading the similar post, stating that algaecides aren't really required for closing, since water temps are generally low enough to prevent algae growth. I'll throw some in anyway.

Thanks a ton.