Green Algae –
is very susceptible to chemical treatment.
Superchlorinate with 10 to 20 ppm chlorine in the evening.
Keep the filter running and brush the pool walls and bottom.
Periodically check chlorine and maintain above 3 ppm until water clears.
Using an algeicide containing quaternary ammonia the next morning will help prevent the return of green algae.
Mustard Algae –
is much more resistant to chemical treatment and clings more tightly to pool walls than green algae.
Adjust pH and superchlorinate as for green algae then brush carefully.
Later vacuum the pool, check chlorine and superchorinate again if necessary.
Mustard algae will generally return unless treated with a special mustard algicide or a copper based (CuSo4) algicide.
should be added in the morning to treat algae in daylight - its most active period.
Black Algae –
can be controlled to some extent by frequent superchlorination and careful brushing with a stiff brush.
(You should have a wire-brush attachment for your telescopic pole).
Spot treatments can be made by turning off the recirculation pumps and pouring granular chlorine directly on recently brushed spots.
You need to use strong algicides and maintenance of relatively high free-chlorine residual, but complete removal of black algae may require draining and cleaning the pool.
Cupper sulfate (34-40% cu)
A very good "shock" for an algae bloom is liquid chlorine - it is cheaps, works quickly, will not harm the pool surface.
It also breaks down into plain water in 1-2 days, leaving no residuals.
Be sure to also algea brush your pool daily to eliminate spores on the pool wall (which chlorine cannot invade).
Good pool hygiene is the best remedy against algae, but you can always try first by using plain Copper Sulphate (CuSO4) crystals dissolved in water.
You can obtain this from a chemicals supplier quite cheaply.
Copper concentration at 1ppm or above in the pool water is a problem.
Staining can be an issue.
A pool concentration of 0.3 ppm – 0.6 ppm is usually considered "algae control" typical level.
Any level above this will likely turn the hair green.
Taking weight ratio, 1 kg. of CuSO4 releases (63.546 g/mole Cu) / (159.61 g/mole CuSO4) = 0.405 kg. of elemental copper in the pool water.
To achieve a target of 0.5 ppm of elemental Cu in 1,00,000 litres of pool water 0.05 kg. elemental Cu is required.
Therefore, the required dose of CuSO4 is (0.05/0.405) = 0.125 kg. for 1,00,000 litres of pool water.
This chemical, when added to the pool water in proper dosage, prevents algae from converting carbon dioxide into the fuel it needs for growth.
It is quite effective.
Another item to look at is the method of sanitation and the type of filtering you have.
Far too many pools out there were sold with marginal filter systems, meant to run 24 hrs per day.
Well, these systems get old and tired, or the new owners only run it 12 hrs per day (or less).
For good algae prevention, you need a combination of good filtration, sanitation and circulation.
Sodium Bromide Algaecide
When you add the sodium bromide and follow with a shock treatment, the bromide is converted into hypobromous acid the active sanitizing form of bromine.
Certain types of algae such as yellow mustard algae and bacterial conditions such as water mold or "pink" algae appear to more vulnerable to bromine than to chlorine.
These problematic conditions, that seemed resistant to shock treatment, are controlled and eliminated by the action of bromine.
It doesn't necessarily work as well against all types of algae and bacterial conditions, but against certain chlorine-resistant problems it is very effective.
While it will help solve the problem and make the water smell and be less irritating, it will increase the chlorine usage.
Mustard algae can be treated in two effective ways and, both are good.
Chelated Copper Algaecides are effective in controlling this type of algae.
The chelated types of copper algaecide will require additions every week or two and this will certainly help, in your case.
The sanitizer level, chlorine, is probably not being maintained adequately at all times.
Make sure that you maintain a 1-3 PPM level of Free Chlorine, at all times.
Do this and it is unlikely that you will see the mustard algae problem returning, with any regularity.
If you don't have an automatic pool cleaner, consider adding a suction-side cleaner to your skimmer intake.
These cleaners are quite affordable and are very effective at cleaning and improving the water circulation on the bottom.
In the case of your above ground pool, it can act as a main drain, while operating.
Another effective treatment for mustard algae is the use of one of those "Yellow" Products, containing sodium bromide.
With a shock treatment, it will generate bromine, which seems to be especially effective against mustard algae.
When shocking a pool make sure that you add enough product and it is added frequently enough to boost the Free Chlorine level to 5-10 ppm.
Make sure that the pH is 7.2-7.6.
Try to maintain at least 1-3 ppm, through the overnight period.
Keep the filter operating continuously, until the problem is controlled.
Once the problem is controlled resume normal chlorination and filtration.
Poor circulation creates dead zones that promote algae growth.
Better circulation assures better distribution of the sanitizing chemicals and makes algae problems less likely.
Algae can grow in swimming pools if nutrients are present and a sufficient level of free chlorine is not maintained.
In addition to properly dosing your water, it is recommended that the algaecide be added in the morning on a bright sunny day for best results.
Algae are plants and grow in the presence of sunlight.
Adding algaecide during algae's best growth time will increase intake of the algaecide and make it more effective.