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.
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.
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.
