Fighting Algae with Borax

[chem geek]

Sumo1,

PolyQuat 60 has no metals in it. I forgot to list copper as an algaecide in my list of ways to keep away algae. Copper is a very effective algaecide, not only for preventing algae, but also for killing existing algae, BUT it comes with serious side effects of precipitating out as blue-green copper hydroxide at high pH causing water to turn greenish (and can stain plaster, too) and also can make blond hair turn green. There are also linear quats as an algaecide, but those tend to foam with aeration so is why we generally only suggest maintaining chlorine levels to keep away algae or using PolyQuat 60 in small amounts mostly as insurance (for prevention, not for getting rid of an existing bloom).

PolyQuat 60 is just a long polymer (which just means a very long molecule with repeating subunits) whose key chemical factor is a nitrogen that carries an extra positive charge with it. So you can imagine this long string of a molecule that has positive charges strung along it sort of like Christmas lights. Most cells, including algae cells, have a negative surface charge so the PolyQuat is attracted to them and will tend to clump them together (in this sense, PolyQuat is also a clarifier and was originally sold as such until it was seen as more profitable to sell it as an algaecide -- it's really both). When attached to the algae cells, the large molecule tends to block the ion channels preventing the cells from getting nutrients (positive charged ions, including phosphates, nitrates and carbonates) from the water. It also has some disinfection capability against bacteria that works in the same manner, but because this process is slow-acting it cannot be used alone (i.e. chlorine is still required) and it does not inactivate (oxidize) viruses.

There should be no problem using PolyQuat in a pool with an SWG.

Richard