ToolboxLab TestingTotal Phosphorus Test

Labeled water sample bottles packed for certified lab analysis

Lab Testing

Total Phosphorus Test

Name: Total Phosphorus Test
Brand: Lake Pulse
Price: 52.00 USD
Availability: InStock

The single most predictive number in lake management, for $52.

$52

Checkout arrives with the store connection. Orders attach to the lake on your account.

Overview

Total phosphorus measures every form of phosphorus in the sample — dissolved, particulate, organic, and inorganic. In the large majority of freshwater lakes, phosphorus is the nutrient in shortest supply relative to what algae need, which means it controls how much algae the lake can grow. Change the phosphorus and you change the lake. Method EPA 365.1, MDL 0.008 mg/L and RL 0.01 mg/L as P.

What's measured & how

1 parameter · Nutrient, single analyte

What's measured & how for Total Phosphorus Test
Parameter	Result type	Unit	MDL	RL	Analytical method
Total Phosphorus	Quantitative	mg/L as P	0.008	0.01	EPA 365.1

Total Phosphorus
Result type:
Quantitative
Unit:
mg/L as P
MDL:
0.008
RL:
0.01
Analytical method:
EPA 365.1

MDL = method detection limit. RL = reporting limit. Provided by the performing laboratory.

You get

Signed laboratory report, filed in your lake's Documents & Reports
Each result loaded into your lake's Data Library (Plus, Lake Admin, PRO)

How it's produced

Test type: Nutrient, single analyte
Sample: One surface-water grab sample, collected by you with the kit
Return shipping: Prepaid 2-day return to the laboratory
Analyzed by: Independent accredited partner laboratory, with full chain of custody
Method basis: EPA-approved
Turnaround: 5 business days from lab receipt
Analytical method: EPA 365.1

Product category

Physical ProductShips to you
ConsumableLab testing

Availability
Kit ships in 2 business days
Shipping
Flat-rate to your front door. Shipping details
SKU
SL-SL-SW-E-S-UI1

Example result

0.018 mg/L as P

Method: EPA 365.1

Mesotrophic range (0.010–0.025 mg/L)

Turnaround

Results are available within 5 business days of the lab receiving your sample.

What problem does this solve for our lake?

If you can only afford one lab test, this is the one. The relationship between total phosphorus and algal biomass in lakes is one of the most reliable quantitative relationships in freshwater science, established across thousands of lakes worldwide. It is the basis for most state nutrient criteria and most lake management decisions.
For orientation: below about 0.010 mg/L is an oligotrophic lake — clear, low productivity, often good for cold-water fish. Roughly 0.010 to 0.025 mg/L is mesotrophic, moderately productive, the condition most recreational lakes are in or aspire to. Above about 0.025 mg/L is eutrophic, where nuisance algae and reduced clarity become common. Above 0.100 mg/L is hypereutrophic, where blooms are the normal summer condition.
Phosphorus reaches a lake from lawn and agricultural fertilizer, eroding soil, failing septic systems, waterfowl, and — critically — from the lake's own bottom sediments, which release stored phosphorus when the water above them runs out of oxygen in late summer. That last pathway, internal loading, is why some lakes fail to improve even after the watershed has been cleaned up, and it is why establishing a phosphorus record before you spend money on remediation is worth doing.
At $52 there is no good reason for a lake to have no phosphorus record.

What's included?

A complete Total Phosphorus 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 accredited 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.
Nitrogen of any form
Orthophosphate, the dissolved and immediately available fraction
Sediment phosphorus, which requires the Total and Reactive Phosphorus Sediment Test or the Phosphorus Fractionation Sediment Test

Requirements

A sample collected from open water at a consistent depth, away from inflows, docks, and stirred-up bottom
Same-day shipment after collection, kept cold
The same site and the same time of year each time, if you want a trend
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.

What you get back

Results

Total phosphorus in mg/L as P with detection and reporting limits
Direct comparison to standard trophic classification thresholds
The foundation of a multi-year nutrient record — the single most valuable dataset a lake community can build
Results load automatically into your lake's Data Library in the Lake Pulse Portal
Data can be charted in the Analytics Hub, used to trigger alerts, or shared with your board and members
A downloadable, signed lab report is filed in your lake's Documents & Reports for permanent reference
Results are found in your lake's portal, accessible only to Plus, Lake Admin, and PRO subscription tiers

Pro tips

Buy several and sample repeatedly. At $52 the sensible pattern is three or four samples a season rather than one. Phosphorus varies enough that a single annual sample is nearly uninterpretable.
Spring turnover and late summer are the two most informative moments. Spring gives you the well-mixed whole-lake concentration; late summer shows you what internal loading has added.
Never stir the bottom. Sediment kicked into your sample will produce a dramatically high, entirely false result. This is the most common sampling error on this test.
Sample deep water too if your lake stratifies. A surface sample in August misses internal loading entirely, which is often the largest phosphorus source in an older lake.
Ten years of this data is worth more than any single expensive study. Start now, sample consistently, and let it accumulate.

Results sync to the Portal for Plus, Lake Admin, and PRO subscribers

Results from this product land in your lake's shared record in the Portal — next to everything else your lake has ever measured, instead of in an inbox.

Compare subscriptions

About these results

Every result shows the date and time the sample was collected. Results reflect one sample, collected at a specific place and depth, and analyzed by an independent accredited laboratory using the method listed on this page. Lake conditions change across a lake and over time, sometimes within hours, in ways a single sample may not capture. Every method has detection and reporting limits; where the laboratory provides them, they are reported with your results. A detection is not a diagnosis, and a non-detection does not prove absence. Results are not a regulatory or compliance determination unless the agency involved accepts them as one. Results can help you make decisions about safe swimming and water use, but no result is definitive for every place and time. It is always good practice to check posted signs and your state or local health authorities. Recommendations are options to consider; decisions, and responsibility for any action taken, rest with you.

Questions on this?

Our team can help you choose the right solution for your lake, explain how results sync to your Portal, or point you to the right subscription.

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