[Fine Edge]

Got a friend who has an acre and a half pond which has some type of algae growth which has taken over the entire surface.
Can someone recommend a good aquatic herbicide which is safe for fish, etc.. and still kill off the invasive predator?
Thanks for the input.

[OptaGreen]

If I am not mistaken Merit can be used.

[NCSULandscaper]

Bluestone aka copper sulfate

[trees]

Copper sulfate is not overly safe for fish. Especially if the KH of the water is low (copper is toxic at 10% of the KH value). In other words, fish in soft water are at much greater risk of heavy metal toxicity than those in a hard water environment.

If it's an algae problem, there's a product called Algae Fix that you can buy by the gallon (don't remember the manufacturer).

During summer (when the water temps are high), any algaecide can cause a fatal drop in dissolved oxygen content as the offending algae die. Dissolved oxygen content is inversely related to water temperature (that's why when it's hot, you'll notice fish hanging out near waterfalls or in deeper, cooler water).

The other thing you may try is to include a couple barley bales into the pond. It takes a couple weeks to start working, but really does control the multicellular algaes (string algae, angel hair algae, blanketweed are some of the names).

[Mark Oomkes]

Originally posted by trees
The other thing you may try is to include a couple barley bales into the pond. It takes a couple weeks to start working, but really does control the multicellular algaes (string algae, angel hair algae, blanketweed are some of the names).

And here I thought barley was for brewing beer.

I'll have to try to get some for my pond, thanks, never heard of it before.

[trees]

Although it is useful for controlling algae, beer certainly is my favorite use for barley.



Wasn't it Benjamin Franklin that said "Beer is proof that god loves us" (or something like that)?

[Paul]

Barley's real purposes is to make nectar, single malt Scotch!

[Fine Edge]

So...... Maybe Merit, a bale of barley straw & it's good to drink beer?
Got it.

[BuenPatron]

I have a customer with two pond systems: 38,000# and 18,000#, full of big honkin' trout.
Jesse is absolutely right. Copper sulfate (Merit, Cutrine) may work, but it's way too risky for the fish and can make your water a weird blue or worse.
Barley mats or bales work pretty well, but take awhile. What works best for me is Bioverse bacteria. It comes in a plastic sorta ball which stays submerged, to which you add bacteria packets (think teabags) which you replace every month or so.

Horizon has 'em. Like barley mats, they take awhile to work...maybe a month... but they're 100% safe for everything and everybody.

Aquascape Designs has similiar products, but they cost more and don't work as well, at least the way I do it.

Another thing to MAYBE try is acid to lower ph to about 7 even. A pool supply co. can sell you a gallon for about 12 bucks. Be careful not to overdo it, though because acid can eat your pump and any non-plastic pipes, and also kill your fish. Plus you constantly hafta monitor ph and carry acid around.

Lotsa cool water plants help too. Bog Buttercup, Water Cilantro. Lilies, Swamp Iris, and on and on. Generally, the ones that float keep water cleanest. Maybe 'cause they shade, or at least cover more surface area. Even duckweed. I have alot of water hyacinth which doubles in about 12 days, but since you're in zone 9 I'd steer clear of that.

None of the water features I maintain (6, but these are the biggest) have any type of filtration at all besides plants, but all are clear. The bacteria starts to work at water temps of about 60 degrees, and it kicks a$$. A little pricey but your customer will think you're a genius, and you won't have to replace any fish.