Had black algea, now I don't know what it its---HELP!

[Kasey]

I had black algea in the bottom of my diamond brite pool. Bought silver algeacide, used as directed and now have something tan to brown colored with what looks like twigs running thru it, have brushed the pool w/wire brush and am dumping muriatic acid in---all other levels have checked out fine---can you tell me what else to do please?

[Backglass]

Why are you adding the acid...is your PH high?

Please post a full set of test numbers....

[Kasey]

Why are you adding the acid...is your PH high?

Please post a full set of test numbers....

I am adding the acid as the pH was high---7.8, plus Pinch A Penny said to throw in one quart for four days
The following are test numbers:
Total Chlorine: 2.0
Free Chlorine: 2.0
Combined Chlorine: 0.0
Acid Demand: 1
Total Alkalinity: 150
Calcium Hardness: 190
Stabilizer: 40ppm
Salt: 2400ppm

Hope this will give you a picture of what is going on, thank you!

[fatybabe]

You should rub some chlorine or bromine tabs on the area affected by black agea but at first use your metal brush to scrap the surfaces before you do so.

That will rid yr black algae.

[chem geek]

Excellent advice for black algae. And by chlorine tabs, these are Trichlor, not Cal-Hypo (i.e. not HTH Duration tabs). The concentration of acid and chlorine from the Trichlor is effective against black algae. Be sure to brush between applications as you need to remove the slime layer to expose areas underneath to the high chlorine levels from the Trichlor.

Black algae grows slowly and is usually an indication of too low a Free Chlorine (FC) level relative to the Cyanuric Acid (CYA) level over an extended period of time (and this can be caused in local areas of the pool with poor circulation). So check your chemistry levels and try and maintain a minimum FC of 7.5% of the CYA level -- a target FC of 11.5% of the CYA level is more conservative for manually dosing (most SWG pools can get away with an FC level of around 4.5% of the CYA level).

Richard

[mr_clean]

I would just be carefull when doing this "rubbing tab" on spot or letting it sit on spot for a while, as depending on what color your diamond brite pool plaster is it can lighten/fade color.
one thing you can do is call the company who did plaster and ask what they suggest to be safe.
Normal black algae treatment for white plaster pools uses 99% trichloro granular that sits on it.

[fatybabe]

Another but more expensive way of doing this is introducing some Black Algea Killers, some copper based but be careful too much might cause you staining.

There are some more expensive brands which the copper based algae killers bonds differently which prevents from staining however as i have said they are expensive.

[Kasey]

Thanks everyone for your help, but now I have MORE tan/brown spots in the bottom of my pool, don't know what to do next----HELP!!!!! Can these be a milder or broken down form of the original black algea and the treatment just was not enough to clear up the problem, or is this mustard algea from the black algea?

[mr_clean]

I would think it's more black algae that has spread. Did you scrub them and they stay there? Have you retested chemicals to see where your at?
Just scrubbing once and adding chemicals once does not mean it's cured.

Daily chemical testing
daily brushing (2-3 times) with metal brush over algae spots and chemical treatment is going to be the way.

you should make sure bottom drain is circulating as much as possible and keep ph around 7.0 to 7.2 to make chlorine stronger only while fighting algae spots and then return to norm.

If the spots are big, rub tab on it and then let tab sit on top for a few hours.Make sure tab is not going to touch to much clean plaster or it can fade it. If rubbing tabs and letting them sit for a while does nothing at all, it could be a metals problem.

You can also buy the more expensive stuff like said above, but nothing is going to make it leave easy. Normally you need more than 1 treatment when it just lightens it or it is spreading.

The safest bet to not damage plaster is contact builder and see what their advise is so plaster does not get damaged in process of fighting black algae.

[fatybabe]

Spread mostly happens with bad circulation and filtration, hwoever before you assume this is algea again a quick check as mentioned in one of the other threads is to use Vitamin C tablets , that way you can confirm the problem before you carry on doing all that scrubbing.

If its an algea problem go as mr clean advised.

[chem geek]

Yes, I was also thinking that these new tan/brown spots might be metal stains since black algae usually doesn't grow that fast. Also, using an algaecide with metal in it (he said it had silver in it -- usually algaecide has copper since silver is more of a slow disinfectant while copper is the better algaecide).

If a Trichlor tab does not fade the tan/brown spots, then it's unlikely to be algae (or anything organic). Instead, it's more likely to be a metal stain. If you lower your pool's pH, that should reduce additional metal staining right away, but existing stains would need the stain remover recommendations as indicated. Usually, brown stains are iron (I have some in my own pool -- long story, I won't get into).

Richard

[Kasey]

Still have the tan/brown spots-----tried Stain Out, looks somewhat lighter, but nowhere near gone. What s/b my next step, please?????

[mr_clean]

If you now think it is a mineral/metal problem you can try this, but be careful with colored plaster trying to put only on stained spot.

Put 1/2 pound of pH reducer granules in a white sock. Shut off the filter. tape the sock to end of pole with duck-tape and drop the sock onto a stained area and leave in place for 15 minutes. Use the pole to move it around after 15 minutes. If improvement is seen, the problem is definitely minerals.

Lower the pH to 6.0-6.5, by the addition of muriatic acid. Let chlorine level drop and when doing this you can use PolyQuat 60 algaecide to keep algae away. Once the pH is lowered, use the brush to scrub the stains. Keep the filter operating and if possible, by pass. Periodically check the pH to see if more acid is required. The acid will etch the upper surface of the walls and by doing so will help remove the pool stains. The same etching would result from acid washing the pool. The lower the pH the faster the removal process. Once the stains are removed, add another dose of metal treatment, prior to raising the pH.
You can also start using metal treatment as prevenative in future

there is one other way to try, some metal treatments also come in a sock with it in granuler form and it sits on stain and removes.

Stains will rarely ever respond just to the addition of a liquid metal treatment.

Like I stated before you can contact builder about this for their info about your pool