Pond Boss
Posted By: Shields08 Blue-Green Algae Problem - 04/17/17 04:58 PM
I have fertilized my pond this spring and all of a sudden the bloom came on strong. First I was excited that the water clarity went from 4ft to 2ft. But then it got thicker and down to 10-12 inches in visibility. The last 2 days I noticed a formation of bright green cloudy algae forming on the top. It is not stringy though. From my short research it appears to be Blue-Green Algae (Microcystis). I assume from over fertilization of my 2 acre pond. This has never been a problem before so I am trying to be proactive and fix the issue. But want to still keep fertile water for my fish. Will it die off on its own or will I need to apply chemicals? I see that allum will deactivate the phosphorus but I don't want to kill the fertility of my pond completely. Aeration is going to be pretty costly around $1,500. Hopefully I can get some good advice and direction, thanks in advance.
Posted By: anthropic Re: Blue-Green Algae Problem - 04/17/17 05:39 PM
Cyanobacteria, commonly known as blue-green algae, can be toxic, so you are wise to be concerned. So long as it is there, you'd be better off not eating the fish nor allowing swimming. If it were me, I wouldn't even hang around downwind of the stuff too long, but maybe I'm overcautious.

Your story concerns me because I just applied fertilizer to my own pond.

Sounds like something has changed in your pond. Maybe buildup of muck over the years, maybe additional fertility coming from your watershed. The real experts here will tell you how best to get rid of the blue-green stuff, but you'd be wise to check what changed your pond's water and how to offset it.
Posted By: Rainman Re: Blue-Green Algae Problem - 04/17/17 06:48 PM
Shields08, 50# of alum per acre foot of water volume will reduce the P in the water and take some of the algae to the bottom to die. Fertilizer, as you now know, is tricky...low doses are always best till you get the bloom wanted. Adding 50% hydrated lime, sprayed in "strips" about 5' apart will shock and kill algae also, often creating a thick froth on the surface from carbon dioxide expulsion. The first rain cleans it up.
Posted By: anthropic Re: Blue-Green Algae Problem - 04/18/17 12:01 AM
On recommendation by Walt Overton, I put in a total of 50 lb of powdered fertilizer into my 7 acre pond. Average depth about 10 - 12 feet, maximum depth 25 feet near dam. Previously we could see down about 40 inches, very light green water. pH 6.5, alkalinity in high 40s.

Is that a high dose, low dose, or about average?

Sorry, Shields, this was meant for Rainman. blush
Posted By: Bill D. Re: Blue-Green Algae Problem - 04/18/17 12:20 AM
Originally Posted By: Rainman
Shields08, 50# of alum per acre foot of water volume will reduce the P in the water and take some of the algae to the bottom to die. ...


Would an appropriate Alum application in the spring be an effective way to help reduce the amount of FA that grows thru the summer by binding a lot of the P, assuming there is not a steady influx of P to the pond?

Reason I ask....I was making good headway against reducing FA in our pond until I made the mistake last spring of allowing two pair of geese to nest on our property. The steady dumping of 10 to 20 pounds/day or so of goose crap in the pond and on shore for a couple months made the FA take off like gangbusters! Now I'm back trying to catch up on the FA battle (NO GEESE ALLOWED this year!)
Posted By: Custom 68 Re: Blue-Green Algae Problem - 04/18/17 01:16 AM
Good question Bill as you saw from my post I'm also fighting some FA (or at least that's what I believe). If the alum is a good treatment I would rather go that route then using Cutrine Plus.
I don't seem to have any suspended clay but the algae has me a bit concerned.

Thanks
Dave
Posted By: anthropic Re: Blue-Green Algae Problem - 04/18/17 04:24 AM
On recommendation by Walt Overton, I put in a total of 50 lb of powdered fertilizer into my 7 acre pond. Average depth about 10 - 12 feet, maximum depth 25 feet near dam. Previously we could see down about 40 inches, very light green water. pH 6.5, alkalinity in high 40s.

Is that considered a high dose, low dose, or about average?
Posted By: Bill Cody Re: Blue-Green Algae Problem - 04/18/17 03:44 PM
anthropic - after the 50 lb of fertilizer, what is the current clarity? how long since the fertilizer? how did you spread it in 7 ac? what was the nutrient rating of the fertilizer? X-X-X
Posted By: Rainman Re: Blue-Green Algae Problem - 04/20/17 02:13 AM
Originally Posted By: Bill D.
Originally Posted By: Rainman
Shields08, 50# of alum per acre foot of water volume will reduce the P in the water and take some of the algae to the bottom to die. ...


Would an appropriate Alum application in the spring be an effective way to help reduce the amount of FA that grows thru the summer by binding a lot of the P, assuming there is not a steady influx of P to the pond?

Reason I ask....I was making good headway against reducing FA in our pond until I made the mistake last spring of allowing two pair of geese to nest on our property. The steady dumping of 10 to 20 pounds/day or so of goose crap in the pond and on shore for a couple months made the FA take off like gangbusters! Now I'm back trying to catch up on the FA battle (NO GEESE ALLOWED this year!)


Bill, I wish I knew the answer to that.....Want to try it and see next spring? I do know alum, at proper rates, will bind to all "available" phosphorus in the water column, and will have at least a minor residual effect on P once the unbinded Alum is on the pond bottom. Treating all algae with Green clean or copper, allowing some time for the decay and release of the P in it, then treating with alum would bind the most P possible.
Posted By: Rainman Re: Blue-Green Algae Problem - 04/20/17 02:28 AM
Originally Posted By: anthropic
On recommendation by Walt Overton, I put in a total of 50 lb of powdered fertilizer into my 7 acre pond. Average depth about 10 - 12 feet, maximum depth 25 feet near dam. Previously we could see down about 40 inches, very light green water. pH 6.5, alkalinity in high 40s.

Is that considered a high dose, low dose, or about average?


Personally, I'd have suggested 2# per acre per week until desired bloom was reached. But without knowing the nutrient blend/qty, it's impossible to sa if the dose was too high, low, or about average.

With a pH of 6.5, you may not see a large bloom from that much fertilizer. If the bloom is less than wanted, I would NOT suggest adding more fertilizer....instead, add liquid lime sparingly to raise pH a few points at a time. It will make nutrients already present, available for uptake, and a bloom....a bonus is adding Calcium, Magnesium, trace minerals, hardness, and alkalinity. Walt's a sharp guy, too!

I recently applied 250 gallons of liquid lime to a lower pH lake like yours. After a month, I will take water samples for a before and after....I also added 300# of Magnesium Sulfate, and about 500# of an "Ice melt" blend of Calcium Chloride, Magnesium Chloride for the addition of the Magnesium and salt.

Lake is 8.1 acres in surface area, and ~64 acre/feet of volume.
Posted By: Custom 68 Re: Blue-Green Algae Problem - 04/20/17 01:56 PM
That is quite a cocktail Rainman, it will be interesting to see how things improve.
Dave
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