Dealing with black algae (Part 1 of 2)

[chem geek]

It's interesting that the black algae is so hearty in your area. It might depend on the specific species. In lab studies by Sommerfeld & Adamson in 1980, Oocystis sp. green alga is the easiest to kill, next is Phormidium minnesotense (Tilden) Drouet black alga, and the hardest is Pleurochloris pyrenoidosa Pasher mustard alga. The chlorine inhibition level for the mustard alga was roughly double that of green alga and black alga was about halfway in between. Of course, they had the black algae free-floating and not adhering to plaster surfaces.

In most pools, having Ben's Min level of chlorine combined with weekly brushing keeps away black algae, at least as far as we can tell from reports on these pool forums. Your situation is (unfortunately for you) more difficult -- possibly due to the heartier local alga species. At least you've found a reasonable way to manage it. I assume you tried other less stringent methods with weekly brushing but were unsuccessful (i.e. the black algae would slowly return).

Richard

[smallpooldad]

Chem Geek,

You are correct on both your assumptions. The black algae, more properly known from reading further, as blue-green or cyanobacteria, as far as can be seen, stays "glued" to the plaster and yes I did try the scrubbing method without great success. See article on it here maybe we can sell it to NASA to grow on the moon as described in external links at end of article.

http://en.wikipedia.org/wiki/Blue-green_Algae


So I suppose it must be made of stronger stuff. We have a saying here "Hawaiian Superman" maybe this is "Hawaiian Super Algae" and no I am not originally from here. The type tested in 1980 must be the "Weak Little Haole" type aimlessly floating around; true according to my wife. For information Haoles translate to puny white people, like me, originally the truer Hawaiian translation meant foreigner among other things, but nowadays it is used mostly as a joke and even as a term of endearment, although it can be derisive, as in "Stupid Haole", not very nice but it helps white persons like myself realize how bad and sickening racism is. Maybe we could sell your type as a pet!

A more complete description of the history of the word Haole can be found here:

http://en.wikipedia.org/wiki/Haole

Mustard algae has not been a real issue on this side, the south, of Oahu although I am told it can be prevalent on the North Shore, why I do not know.

After writing this I had a thought, would not the BBB method work better? It did work well for me for a number of years albeit time consuming.

For those of you that have the time, staying at home most of the time, the answer might be yes. But if you work or travel and your time is not always your own a Salt Water Generator is, to my mind at least, the way to go; it consistenly outputs the correct amount of chlorine.

If one has a digital controller for the acid (highly recommended) the daily tasks of checking can be skipped occasionally; giving piece of mind if one is unable to attend it, again for those of us whose schedules are controlled by others or events.

As always thank you for your reply and knowledge.

PS. If you have any scientist friends here let me know as I know of a pool that has a plentiful supply of the "glue" type. Why because he actually believes his pool person can get rid of it by diveing and scrubbing at $150 an hour! And yes he's a Haole, worse still he comes from the same country I do originally; and only 3 miles from where I lived. Please, please don't tell the Hawaiians, I don't want him and me to end up like Captain Cook.

See the 3rd voyage here:

http://en.wikipedia.org/wiki/James_Cook

[chem geek]

I forgot to mention this earlier, but there is another option that may work for you regarding black algae (or any algae, for that matter) and that is to use a phosphate remover. It's a last resort, is expensive if you've got high phosphate levels or regularly introduced phosphates, but it does work. In some ways you can see this as an alternative to the weekly PolyQuat 60 (and the Borates, though those are just added once and inexpensively maintained), but could let you have lower chlorine levels. By the way, for the heck of it I bought a Taylor phosphate test kit and found that my fill water is more than 500 ppb in phosphates and my pool is well over 1000 -- I estimate between 2000 and 3000 ppb if not more. I'm able to maintain my pool with chlorine alone with no algae (except some green algae inside the skimmer above the water line, but never in the pool itself).

Richard

[smallpooldad]

Chem Geek,

You might be on to something here about "Phosphate Remover".

A little while ago I did add phosphate remover and as I still had such a large bottle of it left I have been using a small dose of it once a week. It seems to help the ORP stay higher and more consistent. Some say because it is dirtying the filter.

I did not want to add that to my post as many persons feel that it is a "Snake Oil" remedy, which indeed it might still be. I too am beginning, however, to have a sneaking suspicion that it might actually be helpful, even though my original levels were far lower than yours on the test being over 200 but under 500.

Maybe we could get on the front page of the "Phosphate Remover Monthly" as originally skeptical converts. I'll call my agent about royalties, 50-50 ok with you?

Seriously I think that maybe something in it is not liked by what little black algae remains secretly hiding out in my pool and that is why the ORP is better and more consistent, although I feel the HOCL above 0.075 is the most beneficial treatment.

Like you I have green algae at the skimmer above the waterline but it is not a problem. Maybe we could invent "Skimmer Algae Remover" and retire!

[CarlD]

SmallPoolDad:

Wonderful exposition! I learned a lot--and clearly your "Black Algae" is not the same species we see in the North Eastern states.

I learned:
1) Don't buy an old pool!
2) If you do, have wire brushes.
3) Don't keep a pool in Hawaii unless you want a lot of work--and if you do, make it vinyl!
4) Hawaiians are just like everyone else--they breed their share of bigots just like the rest of us.

[smallpooldad]

Carl D,

Firstly thank you.

In response by item:

1) True, but as they get older at $8,500 in Honolulu a resurface it is hard for retirees on a fixed income. If one does get it done in Honolulu hire a good concrete engineer ensuring he is on-site to make sure the prep-work is carried out properly, the Portland cement's slump is correct (not too much water), good synthetic additives are used including artificial fibers to strengthen the mix, and then cured properly. No marble chips here.

2) Yes wire brushes are second only to chop sticks. They are even more important than having a cute little Thai or Korean girlfriend for us PoolForum aficionados; well maybe!

3) True, I think that vinyl replacements if purchased locally will cost nearly as much. But buying them from the mainland now that's an idea worth reviewing.

4) Yup, but having lived all over the mainland I think that this is better here. It is good to be in the minority it gives one a better understanding of others plight. And where in the world can you find 300+ lb guys (and girls) with muscles the size of SUV tires, tattoos all over, opening doors for you and saying "No you go first, you only got a few items" That's why I love it here. It isn’t just the cute Thai and Korean girls that make it a pleasure to live here. I swear on my black algae.

Aloha