Algae and pond weed control that treats nutrients, light and circulation
Green water, string algae and pond weeds all come from the same three inputs: nutrients, sunlight and still water. We fix the inputs first, then treat what's left.
Residential ponds
UV clarifiers for green water, mechanical removal and phosphate control for string algae, plant coverage and shade for sun-exposed ponds, and feeding and stocking adjustments where the fish load is driving nutrients.
Lakes and commercial features
Aeration and circulation, beneficial bacteria and enzyme programs, dye for light control, and licensed algaecide and herbicide applications where required. Weed harvesting and bottom-barrier installation for persistent invasive growth.
Signs you need algae control help
- Water is pea-green within a week of a clean-out
- String algae returns days after it's pulled
- Blue-green scum or foam appears on a lake in late summer
- Submerged weeds foul intakes or fishing lines
What drives the cost
Residential algae work is usually folded into a maintenance plan or a one-time UV and nutrient-control package. Lake treatments are priced per acre per application, with aeration and bacteria programs priced annually.
What this service covers
Algae & weed control sits under the wider heading of pond and lake water quality management. Clients tend to call it algae removal or pond algae treatment; whatever the name, the work breaks down into a few distinct jobs:
Green water (planktonic algae)
Suspended single-cell algae; fixed with UV clarification and nutrient control.
String algae (filamentous algae)
Hair-like mats on rock and falls; mechanical removal plus phosphate and flow management.
Blue-green algae (cyanobacteria)
Potentially toxic blooms in lakes; aeration, nutrient control and licensed treatment.
Submerged weeds
Pondweed, milfoil and similar; harvesting, bottom barriers and selective herbicides.
Floating weeds (duckweed, water lettuce)
Surface mats removed mechanically and prevented with nutrient control.
Emergent weeds (cattails)
Shoreline growth managed by cutting, root removal and selective treatment.
Terms you'll hear from our technicians on this work: UV clarifier, phosphate binder, beneficial bacteria, barley straw, aeration, pond dye, algaecide, aquatic herbicide, weed harvesting, bottom barrier.
Where we offer it
Routed service through Orange County, Los Angeles, San Diego County, the Inland Empire and the Coachella Valley, with construction and commercial crews traveling to Arizona.
Algae & Weed Control across Southern California and Arizona
Orange County home base, routed crews from Los Angeles to San Diego and the desert. One call, one crew, written findings.
Before and after: algae control calls
Customer story
A turtle pond rebuilt to run on a weekly back-flush
“Wes and his crew are fantastic. They've been out a couple of times to make it the best possible scenario for everyone. I try to do it as naturally as possible, without chemicals. The bio-filter with the UV light helps immensely. Once a week I back-flush and we're good to go. Clean water. Everybody loves it. The turtles love it.”
Homeowner
A homeowner on her rebuilt turtle and koi pond: Koi Pros added a bio-filter with UV so the water stays clear without chemicals, and the monthly maintenance that used to overwhelm her is now a once-a-week back-flush.
Pond owner tip
Free fertilizer: put your filter backwash water on the garden
“I use the wastewater from backwashing my koi pond filter to water the flowers and plants around my house throughout the year. That's why they look so beautiful! When I have time, I trim them once in a while, too. Using the pond's backwash water means I don't have to buy fertilizer.”
Victoria, Garden Grove, CA
Filter backwash carries nitrates, phosphates and fine organic solids, which is exactly what you'd buy in a bag of fertilizer. Run the backwash line to a bed or a barrel instead of the drain and you remove nutrients from the pond (less algae) and feed the landscape at the same time. Two cautions: let it settle if it's going on potted plants, and skip the garden for a few weeks after any salt or medication treatment.
Check out Koi Pros projects
Koi ponds, waterfalls and water features we've designed, built and maintain across Southern California, in one minute. The same crew handles algae control.
Guides on algae control
Maintenance · 9 min
How to Dechlorinate Pond Water
Learn easy ways to dechlorinate pond water safely for fish and plants. Keep your pond healthy with simple tips and methods.
Maintenance · 31 min
Professional Pond Maintenance: How It Really Works
Confused why algae, fish stress, or equipment issues keep returning? Learn how professional pond maintenance...
Maintenance · 20 min
Seasonal Pond Maintenance in California: Year-Round Care Guide
Seasonal pond maintenance in California covers water chemistry, algae control, equipment inspection, and fish care...
Questions about algae control
Are algae treatments safe for koi?
The products we use in fish ponds are fish- and plant-safe when dosed correctly. We always increase aeration during treatment because dying algae consumes oxygen.