graph, algae growth rates

Stacking up against the competition

The data we have collected on Algae Control shows how effective it is against algae, to dive deeper into how it works we want to look at two different ways our product can be used, not only to cleanup unwanted algae growth but to also prevent the growth from ever occurring.

1) Algae/Cyanobacteria Cleanup

There are many commercially available chemical methods to reduce the growth of unwanted or uncontrolled algae. These products have a small variety of active ingredients with varying degrees of efficacy depending on the target, treatment protocol, and additional environmental factors like geographic location. To help understand how Algae Control fits into the market we have run several experiments comparing our efficacy to leading brands against common species of algae. (experiments tested under controlled conditions to establish a baseline level of efficacy following the addition of a 1% solution to the culture medium) See results below.

Algae and Cyanobacteria Species Tested


  • Chlamydomonas

  • Spirogyra

  • Ulothrix

  • Pandorina

  • Nostoc

  • Scendedesmus


  • Anabaena

  • Nostoc

  • Scytonema

  • Gloeotrichia

  • Oscillatoria

Equal masses of algae or cyanobacteria growth were grown in the presence of each chemical control and compared to growth in the absence of chemical control, the addition of distilled water. After 2 weeks the chlorophyll was extracted from each culture with methanol and quantified using the absorbance at 665nm. The intensity of chlorophyll absorbance serves as a measurement of the total amount of algae or cyanobacteria present in each sample. This experimental setup attempts to simulate a cleanup scenario where the large amount of growth must be removed as shown in figure 1.
2w Cleanup: Mixed Algae
2w Cleanup: Mixed Cyanobacteria

Figure 1. 2 week cleanup scenario following the addition of 1% solution of the leading commercial products (black) and GWL’s Algae Control (standard cocktail green) for the control of cyanobacteria growth (A) and green algae (B).


At a 1% dose the concentration of active ingredients in the GWL standard cocktail is comparable to products currently on the market. The concentrations of active ingredients range from 45-5,500 ppm, figure 2. For many applications like aquariums, aquaculture, or turf management it is important to keep this concentration as low as possible.


Concentration of active ingredients at 1% dosage


Figure 2. Concentration of active ingredients at 1% dosage. Barley* concentration is unknown but assumed 1% by weight.

2) Sustained Growth Prevention

In cases where cyanobacteria and algae growth have been removed as described in the previous section it is important to prevent further growth. This can be accomplished by a continuous dosing program where the chemical control is added periodically to keep growth in check without thoroughly cleaning the entire system. The advantage of this approach is that there is less downtime to operations allowing for a continuous sustained process. Although highly effective at removing algal growth, products like ZeroTol are incompatible with any living organism and therefore a pause in operations is required to flush the system. An alternative approach is to use a targeted algae and cyanobacteria inhibitor that keeps growth in check but does not pose any threat to other organisms. Barley extract and the standard cocktail are not toxic to other organisms such as fish or crustaceans.

Algae and cyanobacteria cultures found Lake Washington were grown in the presence of barley extract, a powder formulation of the standard cocktail, the standard cocktail, and a control experiment to compare the growth rates. Growth inhibiting chemicals were added at time 0 and chlorophyll extracted after 1 day, 5 days, and 14 days exposure to track growth trends. (Figure 3)

Figure 3. Algae growth rates over 14 days.

3. Formulations

The GWL standard cocktail liquid can be formulated into gel or powder form for specific applications, release profiles, or to meet various transportation and shelf life requirements. Gel formulations have slower release profiles that may find utility in preventing surface fowling for example below waterline while liquid formulations can be applied directly as a foliar spray in the case of turf management or added directly to a body of water as in aquaculture. Powder forms are lighter and boast longer shelf life are therefore better suited for long term applications with size and weight restrictions.

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