Chlorophyll-a Test

Overview

Chlorophyll-a is the green pigment every photosynthetic alga carries, so measuring it measures algal biomass directly. Where phosphorus tells you how much fuel your lake has available, chlorophyll-a tells you how much of that fuel has already been converted into algae. It is the standard biomass metric in limnology and one of the three variables — with total phosphorus and water clarity — used worldwide to classify lake trophic condition. Method EPA 446.0. Reporting limit 1 mg/m3, which is the same value as 1 ug/L.

What problem does this solve for our lake?

A lake can have high phosphorus and still look clear, or modest phosphorus and turn green every August. Nutrients set the ceiling; chlorophyll-a tells you how close to that ceiling your lake is running. That distinction matters, because the two situations call for different responses. Chlorophyll-a is also the number that connects the chemistry to what people actually notice. Residents don't see phosphorus. They see green water, they see the dock disappear from view at four feet, they see the summer their grandchildren didn't swim. Chlorophyll-a is the measured version of that experience, and it is what makes a nutrient conversation legible to a board or a county commission. As a rough orientation: under about 2 ug/L is a clear, low-productivity lake; roughly 2 to 7 ug/L is moderately productive; above about 7 ug/L is a productive, nutrient-enriched lake where blooms become likely; and readings above 30 ug/L generally correspond to visible bloom conditions. Your lake's natural baseline depends on its geology, depth, and watershed, so the trend in your own numbers matters more than any single threshold.

What's included?

• A complete chlorophyll-a test kit shipped directly to you
• All materials required for clean, contamination-free sample collection
• Step-by-step collection and preservation instructions
• Prepaid 2-day return shipping to our certified partner laboratory
• Analysis by EPA-approved methods at an accredited partner laboratory, with full chain of custody
• Results loaded automatically into your lake's account

What's not included

• Sample collection. You collect the sample; we supply everything you need to do it correctly.
• Boat, dock, or shoreline access to your sampling site
• Depth-profile sampling. This is a single grab sample unless you order multiple kits.
• Ice or a cooler for shipping, which you supply
• Treatment, remediation, or applicator services
• A written management plan. The Boathouse can help you interpret results and decide next steps.
• Species identification. This measures total algal pigment, not which algae are present.
• Cyanotoxin measurement. Chlorophyll-a does not distinguish harmful cyanobacteria from harmless green algae, and it does not measure microcystin.
• Phycocyanin, the pigment specific to cyanobacteria.

Requirements

• A sample collected from open water at a consistent depth, typically just below the surface
• Protection from light between collection and shipment — chlorophyll degrades in sunlight, so keep the sample dark and cold
• Same-day shipment after collection
• A Plus, Lake Admin, or PRO subscription to have results loaded into your Lake Pulse account
• Questions about site selection, timing, or which test fits your lake? Contact the Lake Pulse Boathouse before you order.