Freshwater algae blooms are the result of excessive nitrogen and phosphorous originating from runoff from fertilizers and household cleaning products. Excessive algal bloom may adversely affect the ecosystem as it causes the depletion of oxygen levels in water and prevents sunlight from reaching other organisms in the water. When microalgae die, the decomposition process also consumes dissolved oxygen and releases nutrients back to the water. This decreases the dissolved oxygen levels in the water and resulting in constant regeneration of microalgae under favorable conditions. This technology relates to an Ultra-Low Frequency (ULF) Algae Control Unit (ACU) treatment system that can be used to control excessive microalgae growth in water bodies. The ULF technology uses an electromagnetic field of ultra-low time-varying frequency range of 100 Hz to 2000 kHz. The ACU comprises emitters and receivers which are energized by a power unit during operations. The ACU creates a disinfecting effect on microorganisms similar to an avalanche current produced in fluorescent tubes.