Algaecide - Will Any Kind Do?

[michaelkingdom]

I am new to pools so bear with me. I have a fresh water pool that I treat with chlorine. My local pool supply recommends this algecide that is $20 per 16oz bottle. I have seen other algaecides that go for $8 per gallon. Is my pool supply ripping me off? Well, I know the answer to that already. They are ripping me off. My real question is, can I use any algaecide out there?

Michaelkingdom

[chem geek]

I am new to pools so bear with me. I have a fresh water pool that I treat with chlorine. My local pool supply recommends this algecide that is $20 per 16oz bottle. I have seen other algaecides that go for $8 per gallon. Is my pool supply ripping me off? Well, I know the answer to that already. They are ripping me off. My real question is, can I use any algaecide out there?

Michaelkingdom

If you don't use stabilized chlorine (Trichlor or Dichlor) after your Cyanuric Acid (CYA) level gets to a certain point (usual levels are 30-50 ppm), then you can manage your pool using unstabilized chlorine alone by making sure the Free Chlorine (FC) level never drops below 7.5% of the CYA level. If you can't or don't want to do this, then a supplemental algaecide will help prevent algae even if the CYA level climbs from continued use of Trichlor, for example. The best algaecide for this purpose is PolyQuat 60 and it is more expensive than less effective linear quats. Mostly, just pick the algaecide that says something like "poly [oxyethylene (dimethyliminio) ethylene (dimethyliminio) ethylene dichloride]" in the ingredients and is 60% of this chemical.

[D0TC]

I would like to simply point out that occasionally it is possible to find a lesser % polyquat available at a price which would make buying it more economical (if you can buy 2 quarts of 30% for less than the price of 1 quart of 60% - you've saved money for the same amount of chem).

I do agree with the other poster that the polyquat is the way to go if an algaecide is required.

[chem geek]

Ted,

Thanks for pointing that out. Usually, the lower percentage PolyQuat has other things in it you may not want, but if it's really just PolyQuat and at a lower concentration, then certainly the "price per percentage" is the thing to look at.

Michaelkingdom,

By the way, another approach towards algae control is to use a phosphate remover, but that can get expensive if you already have moderate phosphate levels. Once you are in weekly maintenance mode, the cost for PolyQuat vs. phosphate remover is similar at around $2 or so per week (depending on pool size). Of course, if you live near fertilized areas where the fertilizer blows in a lot into your pool, then the phosphate levels will climb much more rapidly requiring a higher phosphate remover maintenance dose, but this is unusual.

Personally, I think that just maintaining a sufficient chlorine level relative to CYA is the least expensive approach, though it does require diligence in maintaining the chlorine level. If you want to automate the adding of chlorinating liquid or unscented bleach, you can look at getting The Liquidator which is talked about in this thread.

Richard