Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants PREVENTING Filamentous Algae - Construction Phase

I have clicked on lots of articles that discuss controlling filamentous algae, but they are pretty sparse on information for prevention.

The most universal advice is to limit the nutrients available in the pond that can be utilized for the growth of FA. The first step is to prevent excess nutrients (ag and yard fertilizer, livestock waste, etc.) from entering the pond. The second piece of advice is to have some desired aquatic plants in the pond sequester the nutrients so that less is available to growing FA.

The articles also note that FA initiates growth on the bottom of the pond, or on rocks and plants in the water. However, I could not find any advice on deliberately constructing a new pond to minimize growth of FA.

[Perhaps there is no "design" solution, because FA only requires water, sunlight, and nutrients.]

Does anyone have any good advice or general wisdom on constructing a pond to minimize the formation of filamentous algae?

The only construction advice I have seen is to make the sides with a 3:1 slope to reduce the area available to bottom-growing FA.

Are there any substrates for the bottom or side slopes that inhibit FA initiation sites?

Should I amend some topsoil back into the 0'-3' deep side slopes after sealing the pond to encourage the growth of desirable aquatic plants? (The final clay lifts used to seal my ponds should be relatively barren for a few years.)

If there is not a "construction" prevention/mitigation option, are there any pond design features that would be helpful during the "control the FA phase" that would have a synergistic effect with algaecide treatments, dye treatments, raking, etc.? (Or just make it easier to perform those tasks?)

Finally, I plan on fertilizing my pond if the need arises. Does someone have a link to a good thread that discusses the proper timing of fertilizing to support beneficial phytoplankton combined with algaecide treatments to suppress the undesirable FA and other plants? Or a discussion that adds dye treatments or phosphorous sequestration into the fertilizing/algaecide schedule?

Thanks,
FishinRod

P.S. Does anyone recommend a particularly good PB discussion on FA? If so, please link it or let me know the search terms and I will link it here.

To control Filamentous Algae, you have to control nutrients coming into the pond. I think you have to control Phosphorus the most.

Hello.

Several years ago I did not know anything, my first pond had Yellow-perch and Minnows which disappeared quite quickly.

I didn't feed the fish,

The second year there were scums on the rocks and so much Filamentous algae that I wondered how Yellow-perch could swim.

We cannot control the fertilizer input by the excreta of all the animals that live in the pond an frequent it.
A+

azteca,

I believe you have multiple ponds, including some very small ponds. (?)

Have you noticed a difference in the growth of FA in your various ponds? If so, what features do you think either enhanced the growth of FA, or retarded it?

Rod, I'm no expert on FA. That said, I do have a few impressions from those who really do have expertise.

First, don't fertilize too soon. You want the right temps so phytoplankton can take up the nutrients, not FA. (Too late and pond plants get it, which you may not like.) Generally this involves near surface temps around 60F that are rising and expected to continue to rise for a number of days. One sign is the very first emergence of whatever pond plant is prevalent.

Second, if you feed, get high quality to minimize fish waste. Optimal claims they do a good job in this regard, but you can research for yourself.

Third, some FA isn't bad. First fry need somewhere to hide. You just don't want it to get out of hand.

Fourth, if nothing else, tilapia love FA. If legal in your area, they will control it quite well.

Best of luck, my friend!

Hello.

I have 3 ponds, one with crayfish and minnows, the other 2 perch and crayfish.

I feed the Yellow-perch twice a week.

In addition to the Filamentous algae here are pictures of Scums that I had on the rocks and also on the aeration stones.

I don't have any of that anymore.

If I see that the quantity of Crayfish is low I put 1 Crayfish x foot all around the pond.

In my small pond where I raise small Yellow-perch, I use Frog tadpoles,
There must be no Filamentous algae with the Yellow-perch larvae,
otherwise the larvae follow the Zooplankton inside the Filamentous algae and remain trapped and cannot get out.


Without Tadpole.


You can see lots of video.

https://ibb.co/vs4k32T
https://ibb.co/yyjR1cB
https://ibb.co/P9m90sk
A+

Thanks anthropic.

Those were all ideas I was pondering, but you stated them very concisely for everyone on the forum!

azteca, very interesting.

I thought the hungry crayfish would snip and eat some of your beneficial rooted aquatic plants, and there would then be extra nutrients in the pond to be utilized by the FA.

Your experience shows just the opposite - that the crayfish make a bigger dent in the FA than on your other plants.

I would certainly like to add crayfish to some of my ponds, but was worried they would be mobile enough to move to every pond. (My new ponds are going to be very close together.)

Do you think your crayfish move on to other ponds from the original pond where you create a high population?

I would assume there would be more pressure to move once they consume their preferential foods and/or face breeding season?

Despite my Louisiana roots, never thought about using crawfish as pond weed (southern naiad in my case) control. My place is naturally acidic & infertile, so if the little cuties managed to convert some weed into available nutrients, all the better.

I'll have to buy some extra around Easter & keep them from the boil.

Truly a "multi-use" species!

Ain't gonna happen. BUT since you asked, re: construction. Have vertical sides, and make the pond deep enough so no sunlight gets to the bottom. i.e. a 10'-12' swimming pool with 0 shallow water. Dye the water to minimize sunlight penetration, but you will still have FA growing on the sides where the sun reaches.

Since that is an unrealistic pond design plan, you will need to have critters in there that eat the FA. Tilapia (if legal), crayfish, tadpoles. Minimize nutrients in the water and get as many vascular plants growing as possible. Now if you are going to have a higher fish population and will be feeding then that will make it difficult to balance vascular plants vs. FA (because of the crayfish).

Thanks esshup, that is what I was looking for.

I wanted to know the unachievable ideal design, and then dial it back to the closest version that would be possible for my actual conditions.

Dense populations of crayfish will denude a pond of all aquatic plants and FA and create turbidity issues without presence of predators. I would rather manually control FA than go back to the mudholes I've had to try and reverse manage due to crayfish populations. Again, I STRONGLY discourage stocking crayfish in forage or grow out ponds - they will reproduce exponentially and when forage is scarce will likely migrate to ponds you may not want in search of greener pastures. This has happened at my farm continuously the past 10 years and I'm still battling their effects. Crayfish are very difficult to eradicate - even leaving a pond dry over Winter didn't take them out - a few must have burrowed deep under riprap and managed to survive. I now continuously trap them Spring-Fall and remove 1000-1500 annually on .25 AC trophy lepomis pond.