Regular use of copper as an algaecide ...

[paulshikleejr]

I have started using 7% copper on a regular basis to control algae. The label says to use four ounces every two weeks for a 20,000 gallon pool and I use a bit more than four ounces every two weeks because my pool has a bit more water than that.

This seems to work well.

I recently heard that using copper regularly this way actually isn't a good thing.

Is this correct?

If so, how "good" a thing is copper to a pool? Is it not really good and to be avoided?

Thank you!

[PoolDoc]

Hi Paul;

Welcome to the forum!

Like many things, copper has good and bad points.

The good is a short list, and not one that endears it to me: it kills algae and inhibits bacteria.

The bad is a longer list:

• It does NOT kill bacteria;
• It does nothing to viruses, often the culprit in person to person infections;
• It turns light (blond, white) hair green;
• It stains pools, sometimes very badly;
• It's not really compatible with chlorine, which still has to be used.

You can reduce some of copper's problems, by not using chlorine. And, with care and some tricks, it's possible to keep a lightly used pool or fountain clear with not much more than copper. But you give up on actual sanitation when you do, and that's a pretty heavy price to pay. You also give up on oxidation -- burning up the trash from sweat, pee, and oils -- with copper. And, if your pool gets much use at all, that's a huge problem.

Your choice, of course.

Ben

[CarlD]

I'll be a little more direct than Ben.

Don't use copper to keep algae away.

A better and more compatible algaecide is called PolyQuat. It's called Black Algae, Mustard Algae or just algaecide. But the key is the SOLE active ingredient is 60% Poly......<something long and unpronounceable>.... If you add about 1-2 ounces a week, if your FC falls a bit low it will inhibit algae. But it's better to keep your FC up to the maintenance levels suggested by the "Best Guess Chlorine Chart" (see Ben's sig for the link). Copper turns blond hair green and stains pools.

Carl

[paulshikleejr]

The information contained in http://www.poolforum.com/pf2/showthr...-amp-More-quot and http://www.poolforum.com/pf2/showthr...-an-algaecide-... are very helpful and the background for the question hereafter.

In the latter thread, it is stated that copper is "not really compatible with chlorine". Based on what's said in that thread and in the FAQ (the first URL above), I understand that copper is deemed not compatible with chlorine because levels of chlorine sufficient to properly sanitize a pool will make it very likely (if not a certainty) that staining of hair, plaster, etc. will occur.

Is that correct?

In the FAQ, it is written that "if there is copper in your pool, high chlorine levels will increase staining ..." I'm asking this question because it's not clear to me whether "high chlorine levels" means 2 ppm or 5 ppm or something else.

Thank you!

[Watermom]

I'm going to ask Ben to look at your post as he is more familiar with the use of copper in a pool.

I'm also going to merge your two threads. Better to keep the questions about copper all within the same thread instead of starting another one.

[CarlD]

I don't know what level of FC starts copper staining, and it may vary depending on the stabilizer level. But none of us (Admin, mods, experienced posters) use copper because we all have found, or feel, that copper is more trouble than it's worth and that following the B-B-B method makes copper algaecide unnecessary.

Carl

[chem geek]

The level of copper needed to prevent algae growth even when chlorine levels get to zero is high enough to cause staining of pool surfaces if the pH gets higher towards 7.8+ depending on copper level, though you can get staining at lower pH if you don't manage your copper level and it gets too high. The incompatibility with chlorine is really referring to incompatibility with hypochlorite sources of chlorine (e.g. bleach, chlorinating liquid, Cal-Hypo, lithium hypochlorite) since raising the chlorine level higher as with shocking or even less than daily dosing will raise the pH and that is what can cause staining. If one uses Trichlor tabs, the pH is usually easier to keep lower which can help prevent staining, but the rise in CYA levels over time can still have the water become cloudy from slower and slower oxidation of bather waste (including lotions and oils). Also, copper can turn blond hair greenish.

If you have a vinyl pool, you are at less risk for staining, but if you have a plaster or fiberglass pool, you are taking chances by using copper. Metal staining is a real pain so why take that chance?

Copper is completely unnecessary to prevent algae growth. Algae can be prevented by chlorine alone if one maintains an appropriate Free Chlorine (FC) level relative to the Cyanuric Acid (CYA) level as shown in the Best Guess Swimming Pool Chlorine Chart.

[PoolDoc]

Looks like the topic's been covered. If you want more than that, probably we need a new thread in the China Shop.

The simple summary is that, whatever you can do with copper in pools (fountains might be an exception) you can usually do better without it.

Good luck.

Ben