Algae Treatment Restores Safe Swimming at a Community Lake in Ohio

Introduction

Two consecutive seasons of safe swimming, achieved without chemicals and independently verified.

Algae treatment for a community lake became a priority for Silver Lake Estates, Ohio, after recurring toxic blooms led to swim advisories over multiple summers. Silver Lake is a private community lake serving over 460 lot owners who rely on it for swimming, boating, and fishing throughout the summer season. The Board of Trustees maintains the lake as a recreational resource, where clear water is part of the enjoyment of living in the neighborhood.

In 2023, microcystin (a liver toxin produced by cyanobacteria) exceeded Ohio EPA’s recreational limit in every month of peak season. Swim advisories limited lake enjoyment during prime swimming season.

In spring 2024, the Silver Lake Estates Board of Trustees deployed two LG Sonic MPC-Buoys: solar-powered, chemical-free systems that monitor water quality around the clock and apply targeted ultrasonic treatment before blooms take hold. The results: two consecutive summers of safe swimming, with improvement across every measured parameter, independently verified by EnviroScience Inc., which has monitored the lake continuously since 2016.

The Challenge  

Silver Lake faced compounding conditions that caused harmful algae to return each summer.

Toxic blooms exceeding Ohio EPA thresholds. In 2023, cyanobacteria reached 168,000 cells per milliliter. Ohio EPA’s high-risk threshold is 100,000 cells/mL. The lake exceeded it by 68%.

Microcystin above the safe limit throughout 2023. Ohio’s recreational safety limit for microcystin is 8 µg/L. In 2023, every monthly peak at the beach location exceeded that limit. The highest reading was 14.8 µg/L in May, nearly double the threshold. At those concentrations, skin contact causes irritation and rashes, while swallowing the water can cause nausea, vomiting, and diarrhea.

A declining multi-year trend. EnviroScience’s long-term monitoring showed water quality declining from 2020 through 2023, with the most elevated algae and toxin readings occurring in 2023. In addition, surface phosphorus and nitrogen ran above Ohio water quality targets during this period, creating conditions in which cyanobacteria thrive.

Algae Treatment for a Community Lake: The Solution

In spring 2024, the Board of Trustees deployed two MPC-Buoys, positioned to cover Silver Lake’s full surface area. Each buoy is solar-powered, operates autonomously, and requires no chemicals.

How the algae treatment works. Cyanobacteria maintain their position near the water surface using gas vesicles, tiny air-filled structures that keep cells buoyant where light is available for photosynthesis. The MPC-Buoy emits precisely tuned ultrasonic waves that disrupt these vesicles. Without buoyancy, the cells subsequently sink to deeper water where there is not enough light to grow.

Crucially, the cells remain intact as they descend. This is the critical difference from chemical treatment: copper sulfate and other algaecides rupture cell walls and release microcystin directly into the water, thereby requiring a swimming ban for days or weeks afterward. Ultrasound, by contrast, causes controlled sedimentation. The toxin stays locked inside the cells as they settle naturally into bottom sediments, so residents keep uninterrupted access to the lake throughout the season.

Real-time monitoring drives every decision. The buoys continuously measure chlorophyll-a (total algae biomass), phycocyanin (a pigment specific to cyanobacteria, which distinguishes toxic species from harmless green algae), dissolved oxygen, pH, and temperature. All data streams to LG Sonic’s MPC-View cloud platform, where the system automatically adjusts ultrasonic output to match the species present. As a result, the community stays ahead of blooms rather than reacting after they form.

Measurable Results

Silver Lake’s improvement was documented by EnviroScience Inc., whose monitoring record going back to 2016 provides a nine-year baseline for evaluating algae treatment results at the community lake.

Microcystin Toxin Levels: 2023 to 2025

Ohio EPA recreational limit: 8 µg/L. Peak monthly readings at the Silver Lake beach location:

Water Clarity Improved Through Summer: For the First Time

Secchi depth measures how far you can see a disk lowered into the water; the deeper the reading, the clearer the lake. In every year prior to 2024, Secchi depth at Silver Lake declined from May through August as algae bloomed. In 2024, however, that pattern reversed for the first time in the monitoring record: clarity improved through the summer instead. Furthermore, the reversal held through 2025.

Cyanobacteria Moved from High-Risk to Moderate

After deployment, cyanobacteria counts dropped below Ohio EPA’s 100,000 cells/mL high-risk threshold for the remainder of the 2024 season. In 2025, counts held steady in the moderate-risk range of approximately 36,000 to 42,000 cells/mL throughout the season, well below the high-risk level.

Surface Phosphorus Meets Ohio Water Quality Criteria

By 2024, surface total phosphorus dropped to 0.034 mg/L, meeting Ohio’s Erie-Ontario Lake Plain water quality criteria for the first time in recent monitoring history. Compliance then held through the full 2025 season.

Discussion

What makes the Silver Lake data compelling is not any single number. Rather, it is that every indicator reversed direction at the same time, and stayed reversed.

From 2020 through 2023, water quality declined each season, with denser algae, higher toxin readings, and lower clarity. Then in 2024, the first full season of algae treatment for the community lake, every trend changed simultaneously. Algae density fell by more than 70%. Toxin peaks dropped well below the safety threshold. Water clarity improved through summer instead of declining. Swimming continued through the full season.

2025 confirmed that 2024 was not a seasonal anomaly. All results held. Cyanobacteria remained in the moderate-risk range all season. Phosphorus stayed compliant. As a result, families enjoyed a second consecutive summer of safe swimming.

EnviroScience Inc. documented the turning point in their November 2024 Water Quality Monitoring Report:

“2024 marked a notable improvement in lake water quality. This was the first year where Secchi depth increased from May to August, indicating improved clarity through the recreational season. Surface total phosphorus now meets Ohio’s Erie-Ontario Lake Plain criteria. Microcystin-producing cyanobacteria were significantly reduced compared to 2023, with only one instance of microcystin exceeding the recreational threshold.”

— EnviroScience Inc., Silver Lake Water Quality Monitoring Report, November 14, 2024

For a community that manages its lake as a shared recreational resource, these numbers mean one simple thing: the lake stayed open and safe through two full seasons.

Conclusion  

Silver Lake demonstrates what sustained algae treatment for a community lake achieves over time. This was not a one-season fix but a documented recovery across every measured parameter. Two full seasons of independent data confirm it: toxin levels down, algae density reduced by up to 81%, the water clarity trend reversed, phosphorus compliant, and safe swimming throughout.

For HOA boards, lake trustees, and community managers dealing with recurring harmful algae blooms, Silver Lake shows that chemical-free algae treatment works and keeps working season after season.

“This was the first year where Secchi depth increased from May to August, indicating improved clarity through the recreational season.”
EnviroScience Inc., November 2024