Tiny Bubbles

[New At This]

I am a new pool owner and trying to get the hang of keeping the water in balance. Ten days ago our 20K gallon pool had a green hue, which I figured was algae. The pH was also high, and chlorine was low. I added a quart of algaecide and some bromide tablets. The green hue is now gone, but I have tiny bubbles floating on the surface. They look like ice flows, but are actually bubbles. What did I do wrong? What corrective action do I need to take?

[chem geek]

The algaecide you used was probably an inexpensive "linear quat" algaecide. Look at the ingredients and you'll probably see something like "Alkyl dimethylbenzylammonium chloride". Such algaecides often foam. The algaecide will slowly break down over the next few days and the foam will subside.

A better algaecide to use for algae prevention is PolyQuat which will have a sole ingredient of 60% "Poly{oxyethylene (dimethyliminio) Ethylene (dimethyliminio) ethylene dichloride}". It prevents algae and is non-foaming, though you need to add it every week.

You can also prevent algae from growing by simply maintaining an appropriate Free Chlorine (FC) level for your Cyanuric Acid (CYA) level. This may mean switching from using stabilized chlorine (e.g. Trichlor pucks or Dichlor powder) to unstabilized chlorine (e.g. chlorinating liquid or 6% unscented bleach). Read more about maintaining a pool at the Pool School.

Richard