Notice of Aquatic Treatments for Lagoon Weed & Algae Control

2026 NOTICE OF AQUATIC TREATMENTS FOR

LAGOON WEED & ALGAE CONTROL

This annual notice is to inform residents that the BLPOA intends to have its licensed applicator apply approved aquatic herbicides, and BLPOA employees apply permitted non-herbicide additives, as needed, to supplement mechanical removal of invasive and nuisance Lagoon weeds and algae.

During the summer, the BLPOA conducts a campaign to control algae, wireweed, and widgeon grass in the Lagoon, primarily through mechanical removal of these nuisance species. To supplement these efforts, approved aquatic herbicides and non-herbicide additives are used around the perimeter of the Lagoon. 

Approved aquatic herbicides are also used, typically applied every three to four weeks, as needed, between April and October. Following California regulations, the licensed applicators wear protective clothing and respirators while working with some of the approved chemicals.

The State Water Resources Control Board approved the following aquatic herbicides and adjuvants mixed with the herbicides as safe to treat the lagoon:

• Diquat Dibromide (potential brands used: Alligare® Diquat Herbicide, Tribune, Reward): used for the control of widgeon grass and algae. 

• As per the product label: For aquatic uses, do not enter treated areas while treatments are in progress.

• Imazamox (potential brands used: Imox, Top Deck, Castaway): used primarily for the control of widgeon grass and potentially also other nuisance species. 

• As per the product label, there are no restrictions on swimming or fishing.

• Hydrogen Peroxide and PAA (potential brands used: GreenClean 5.0): used primarily for the control of algae and potentially also non-beneficial bacteria. 

• The product label does not state any swimming or fishing restrictions.

• Sodium Carbonate Peroxyhydrate (potential brands used: PAK27, GreenClean Pro); used for control of algae, particularly when oxygenation is helpful. 

• The product label does not state any swimming or fishing restrictions.

• Approved Aquatic Surfactants (potential brands used: Cygnet Plus®): used to improve the efficiency of the herbicide, particularly diquat and imazamox, thereby helping reduce the amount of herbicide treatment required. 

• The product label does not state any swimming or fishing restrictions.

In an abundance of caution, the BLPOA recommends avoiding swimming or fishing in the lagoon before 5:00 pm the day of treatment with aquatic herbicides. 

As an additional reminder, we also intend to email members alerting them to the details of each individual treatment two days prior. 

After treatments, you may see a black residue or clumps in the lagoon which is the dead algae, wireweed, and widgeon grass. While unsightly, there are no use restrictions while this condition exists.

Additionally, the BLPOA may also use selected non-herbicide additives to further control aquatic weed and algae growth:

• Light Attenuating Water Dyes (brands used: Cygnet Select® Blue Lake and Pond Dye): used to reduce sunlight reaching aquatic weeds and algae that can stimulate plant growth. 

• As per the product label, allow several hours for the product to disperse before fishing or swimming.

The BLPOA recommends avoiding swimming or fishing following dye applications until the dye has visually dispersed.

The BLPOA does not intend to send any further notices during the year regarding applications of these non-herbicide additives.

In addition to the above treatments, all BLPOA members, tenants and their guests should pay attention to seasonal rain and avoid swimming or fishing in the lagoon for at least 72 hours after rainfall as runoff from storm drains occurs. 

The BLPOA Maintenance Team performs regular water quality tests and will advise members if tests indicate swimming and fishing in the lagoon should be avoided.