Just spent most of yesterday on google identifying my latest pool problem......'the dreaded black algae' , often refered to as 'the herpies of swimming pools' because it's so hard to cure.
Read a lot of conflicting info on how to combat it and it seems, short of draining the pool and scrubbing it down completely, the two recomended cures are super shock cholorine [done that and still have the algae] and the other cure was copper sulfate which I have a couple of kilos of.
I then googled dosage retes? of copper sulfate and couldn't find any definate rates of application.

to illustrate the conflicting and misinformation I found....read the following.

CONTROL OF ALGAE AND BACTERIAL ODOR IN SWIMMING POOLS
Apply 1 to 2 lbs. of Copper Sulfate Crystal per 60,000 gals. (3,000 cu. ft.) of water. This will result in a concentration

of 0.5 to 1.0 ppm of dissolved copper. Dissolve the required amount of copper sulfate in a plastic container and pour

the solution into the pool. Use the higher rate where visible algae are present. For maintenance dosages, use the

lower rate. Repeat the lower rate to control the recurrence of algae and avoid the buildup of copper. Copper Sulfate

Crystal may be used to help control pool odors and algae during the winter months. Apply the higher rate while the

pool is not being used during the winter. Treated pool effluent should not be discharged where it will drain into lakes,

streams, ponds, or public water.



Don't know if you caught the conversion mistake "60,000 gals. (3,000 cu. ft.)".....it don't add up, so who can you trust?? 60000 gallons (US) is equal to 8,020.83 cubic feet

Does anyone out there have any experience with black algae and/or copper sulfate dosage rates??
Please share info.....

The article you posted about killing & controlling algae did not specifically mention black algae which as you rightly say is extremely difficult to remove as it actually roots into the grouting. One way to get rid of it is to suffocate it with flocculent & the name escapes me right now but I think it is ammonium bisulphate. It should be readily available all over the country as it is commonly used after digging a bore to make the water clear.

Actually, I missed the copy of the article and only posted it to show the lack of info available on copper sulfate dosage rates. I've since signed up on a very informative pool forum and have several possible solutions....all of which involve a lot of brushing to remove the roots of the dreaded black algae and my bad back is not up to that chore at the moment.

"One way to get rid of it is to suffocate it with flocculent & the name escapes me right now but I think it is ammonium bisulphate. It should be readily available all over the country as it is commonly used after digging a bore to make the water clear."
I've used an alum [hydrated aluminium potassium sulfate] which is aluminum based as well as PAC [don't know what that is, but it's an effective yellow powder that acts as a flocculent] for flocculents, but didn't know they would 'suffocate' the algae. are you sure of that??


FYI, the forum that I just signed up on is http://www.troublefreepool.com/index.php andtopics are all pool related and seems to be quite well run. I would strongly recomend it to all pool owners.

I have used alum successfully in the past & is a lot less backbreaking than scraping & brushing but you lose some water when you vacuum it out which has to be done very slowly. Another more simple method to try is to scrape the black algae with a chlorine tablet which can be quite effective. Once you clear the problem I suggest you use a new product which will keep algae at bay. PM me if you want details.

Have your water tested for phosphates. They are often the culprit when severe algae problems occur. anything over .5 ppm is likely to cause a lot of trouble, but .1 ppm or less is optimal. Lanthanum is best to floc the phosphates with, followed by vacuuming the bottom to waste, not the filter.

After that, a super-chlorination followed up by regular algaecide treatments.

A proprietary product is sold in pool shops throughout Thailand for between 1,750 and 2,220 baht a US 1 gallon bottle (3.78 litres). This price is of course a typical 'luxury goods' label of the kind aimed at the rich retirees such as former golf pros and rock stars skulking in the Pattaya hinterland. For those of us of a more modest financial disposition, if we suffer from it, treating black algae will probably be a permanent feature of living with a swimming pool, and can become a costly and permanent part of our budgets.

Shopping around carefully will however reveal that the said algaecide can be purchased at almost half the pool shop retail prices. However, you may have to buy a minimum of four or more bottles to get those prices.