New to forum, black algea problem.

[PoolDoc]

Is it OK to abandon the BBB for a moment and hit it with some algeacide? This stuff has got to go, I am embarrassed by the way it looks.

There's nothing that is compatible with human swimmers that will eradicate black algae within a few days. Available algaecides are ineffective against black algae, and by ineffective, I mean much less effective than chlorine.

VERY high levels of monochloramine (ie, Yellow OUT) would be probably be effective if sustained, especially if combined with a phosphate detergent, like STPP which is included in several companies anti-algae products. But doing so would leave you with a huge chemical mess to clean up. Plus, creating and sustaining high monochloramine levels requires an attention to detail missing from most pool owner's dosing methods.

Not to put too fine a point on it: but your black algae didn't suddenly appear (if it did, it's not black algae) and it's not going to suddenly disappear.

Of course, if you go in a pool store, insisting you want to get rid of black algae RIGHT THE HECK now, you are going to end up a mark for a predatory pool salesman.

If you are really determined to get rid of it completely, and are willing to 'do what it takes', do ALL these things:

1. Go to the test kit page, and order BOTH a K2006 and the LaMotte borates strips ASAP.

2. Go to Walmart and buy, for each 10,000 gallons of pool water, 10 boxes of 20 mule team borax. Go to Lowes, etc. and buy 3 gallons of 31% muriatic, per 10K gallons. Begin adding 4 boxes of borax -- slowly to the skimmer with the pump on -- followed by a gallon of muriatic. After adding the last of the borax, add the last gallon, 1/4 gallon at a time, till your pH is between 7 and 8.

3. Buy 2 quarts of KemTek phosphate remover per 10K gallons: Kem-Tek 265-6 Pool and Spa Phosphate Remover, 1 Quart and a phosphate test kit: Taylor Technologies Inc K-1106 Test Kit Phosphate

4. Buy some GLB clarifier: GLB Pool & Spa Products 71404 1-Quart Clear Blue Pool Water Clarifier

5. Begin dosing with phosphate remover every few days to lower your phosphate levels to below 100ppb . Use small doses, per the label of the clarifer, to help quickly clear up the cloudiness from the phosphate remover.

6. Make sure you are running your pump 24/7, and brushing the black algae spots every 2 -3 days.

7. Make sure that your chlorine level stays at the shock level ALL the time. Use the Best Guess chart to find the appropriate level.

8. There are other things, you can do, but you'll have to report details on your pool finish & volume, and your pump and filter before I can mention those.

What you must understand is that NONE of those things will suddenly eradicate black algae. Black algae grows when you neglect the pool. But unlike other forms of algae, it sends roots down in fine cracks and crevices of the pool, where you CAN NOT reach, either physically or with chemicals. Even after you kill the exposed algae, the roots remain.

We don't normally recommend phosphate removal -- but if you lower phosphates enough, and KEEP them low, you will make it harder for the black algae to recover. We're not really sure why borates reduce algae's ability to grow, but it seems to. Chlorine will kill algae, but it has a hard time penetrating the film on top of black algae. Brushing helps.

The reason I mentioned all those things -- phosphate removal + borate addition + high chlorine adjusted for CYA, is that you can do all those and still swim. Plus none of those interfere with each other. By contrast, all algaecides are at least some what incompatible with chlorine (even polyquat, though it's the most compatible).

Other steps that depend on your equipment:
=> DE on your filter, but only if you have a sand filter. Helps remove precipitated phosphates
=> Brushing with an SS bristle pool brush, but only if you have a unpainted plaster surface
=> Dropping granular cal hypo on the algae, but only if you have a concrete pool and fairly low calcium levels
=> Dropping granular trichlor on the algae, but only if you have a concrete pool, and reasonable stabilizer levels


But NONE of this will matter, if you don't solve the original problem, of erratic chlorine levels, that resulted in the black algae in the first place.