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Beach Ball in Pool

Algae & Blackspot


POOL DROPS PLUS & POOL BLOCKS are extra strength, long term algicides compatible with salt water, ozone, ultraviolet and chlorine outdoor pools. They Eliminate all forms of Green, Mustard and Blackspot Algae Long Term to deliver outstanding results in harsh environments. Using these Algicides regularly Stops your Pool from Turning Green when Chlorine Levels Fall. Making Pool Care Simple while Saving you Money.


Blackspot, Mustard & Green Algae Killer
Eliminate Algae from Walls, Grouting & Steps
Reduce Chlorine Consumption
Handy Once a Season Dosing Liquid
Ideal for Salt, Chlorine, UV & Ozone Pools
Long Life Algicide for Summer & Winter
Makes Pool Water Sparkling Clear


These are an ideal first step in your pool maintenance regime to provide a constant low level of algicide which both protects the pool water and the pool walls from all forms of free floating and wall based algae growth. Once treated, the pool water stays visually clean and crystal clear even as the chorine level rises and falls. By eliminating all algae cells, spores and associated organic matter from the pool water and walls, much less chlorine is required to maintain correct sanitiser levels. Chlorine consumption and running times can be reduced by around 50% to just four to six hours per day. In the non-swimming months, POOL BLOCKS or POOL DROPS Plus are the most effective winterisers available and will control all algae even without chlorine. The principal task of chlorine is to destroy bacteria and much less is wasted on organic matter once the water is treated with with our long term products, a small dose of chlorine is required to kill bacteria alone.

Do they kill blackspot algae?

Yes, POOL BLOCKS and POOL DROPS Plus are one of the few effective treatments against blackspot algae which is common in all types of swimming pools. Chlorine has no effect at all on blackspot algae as only a specific long term algicide destroys the algae cells. Some scrubbing is helpful during treatment to remove the waxy protective coating that forms on the exterior of the blackspots. Tough, wall based algae such as blackspot grows slowly and dies slowly and a full three month treatment period is required to kill all living cells and this is why short term algicides so often fail. Once the algae is dead, only the mineral remnants of the spot remain and this is mostly composed of calcium and can either be scrubbed off with a stiff bristled brush or a follow-up acid treatment with citric acid can be used to breakdown the dead remnants left behind. This follow-up treatment involves lowering the pH of the pool water with citric acid (which dissolves organic marks) and sometimes some additional hydrochloric acid is required to further lower the pH to around 6.0 for about a week, then the pool is rebalanced back to pH 7.2 and any remaining spots are scrubbed away.

How do POOL BLOCKS and POOL DROPS Plus work?

The natural trace element copper has been used for centuries to inhibit algae growth and has been used for many decades as the active constituent of hundreds of algicide products available worldwide. Our high performance products also include a complex blend of non-active ingredients which result in the active copper ions being very readily absorbed by the algae cells at low levels (just 0.4 to 0.8 ppm). This low level is in line with both the Australian and World Health Organisation recommendations for drinking water at 1.0 ppm and also private swimming pool water quality (AS3633-1989) also at 1.0 ppm. Naturally occurring copper is an essential human nutrient found in hundreds of food items such as nuts, beans, peas, chocolate and fruit juices at higher levels between 1.0 and 20 parts per million.

Why do POOL BLOCKS and POOL DROPS Plus work so well?

The secret to the superior performance of our unique products is that they are "made stronger to last longer". Where standard algicides provide a single small dose of algicide which lasts just a few weeks, POOL BLOCKS provide five "once a month" treatment tablets in the one 1.5 Kg container that lasts four to five months in an average pool. POOL DROPS Plus are two to three times the strength of all standard strength liquid algicides, and also last for an entire three to five months treatment period even in testing climatic conditions. The number one reason most algicide products fail is that they simply do not provide the treatment period sufficient to give effective long term results. Algae grows slowly and dies slowly and an effective algicide product must provide several months treatment to work effectively.

Which product is best for my pool?

Over many years, we have found POOL BLOCKS work best in fibreglass and vinyl lined pools where the pH is most often quite neutral around 7.2 to 7.6. Our liquid product POOL DROPS Plus can be used in all types of pools as they perform very well over a much wider pH range. They are especially effective in pools with alkaline pool surfaces such as concrete, pebblecrete and marblesheen or where the pH is typically higher than 7.4 most of the time. With correct pH control in the normal swimming pool range of 7.2 to 7.6, you can choose either product based upon whether you prefer the ease of a 'once a month' application or the simplicity of a 'once a season' treatment (three monthly treatment period).

Do I still need chlorine while swimming?

Yes, chlorine is required when swimming to control harmful bacteria. Once our highly effective products eliminate all algae from the pool, less chlorine is required to maintain minimum levels of free chlorine; 1.0 ppm in unstabilised pools, 2.0 ppm in stabilised pools, and an additional 1.0 ppm where the pool water exceeds 26 degrees Celsius. In the non-swimming months, our effective long term algicides keep most pools sparkling clear and free of all algae for months at a time without any chlorine at all. Just a weekly dose of chlorine in winter is helpful to bleach leaf marks and debris from staining.

Do I add POOL BLOCKS as they dissolve?

No, our solid algicide tablets are designed to be a slow release treatment which dissolve fully in the skimmer basket over several days, but treat the pool water for an entire calendar month. If POOL BLOCKS took an entire month to dissolve, they would work far too slowly. Once dissolved in the water, our algicides are used up controlling algae cells and spores at a constant rate so simply add them as they are due on the calendar as per directions.

How often are POOL DROPS Plus added?

Our unique long term liquid algicide is added just "once a season" in an average size 50,000 litre swimming pool. POOL DROPS Plus are a potent double strength algicide formulation and we get superior results by adding the one litre bottle at the start of each season for long term product performance and protection against all forms of algae. The additional active ingredient simply stays in the water longer and is used up at a constant rate on algae cells and spores which enter the water.

When adding POOL DROPS Do I need to turn off my Salt Water Chlorinator?

The directions for use for POOL DROPS LIQUID ALGICIDE PLUS ask you to turn off your salt water chlorinator for the day when you add the product. If you can add the Algicide so that it is fully diluted as per the recommended dosages by the time it reaches and passes through the salt water chlorinator cell then you do not need to turn off the chlorinator. We recommend that you add the product around the edges of the pool furthermost away from the filter water intakes. If you are uncertain then you are advised to turn off your Salt Water Chlorinator until the Algicide is fully diluted as per recommended dosages.

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