Fyfer says:
The logic of the aerator, as far as I understand, was just to keep some area of the pond open during the winter to reduce spring weed growth. I am not sure as to why that is supposed to work. Is keeping some water open on ponds that are frozen for a fairly long time a way of reducing weed growth.
I think keeping ice and snow cover less in a pond with curly leaf pondweed will enhance not hinder the growth of curly leaf. Curlyleaf is considered a cool water plant. Plants need sunlight for good health. So my thinking is more light to them due to more open water in winter helps them survive not hinder them.
Your manager suggested product of Nature's Pond Conditioner is very likely an enzyme + microbial bacterial product. According to Dr. Claude Boyd, as a distinguished and well known, extensively published professor emertius in School of Fisheries, Aquaculture & Aquatic Sciences, Auburn University in Alabama, USA, Bacterial Amendments do not enhance water quality in ponds. Dr. Boyd regularly writes a water quality article in every PBoss Magazine.
In his Nov-Dec 2017 Pond Boss magazine article - "Do Microbial Amendments Improve Water Quality in Ponds?", he says he tested microbial amendments in several studies in aquaculture and sportfish ponds. Tests showed very few instances where the concentration of one or more water quality variables improved following additions of bacterial based products in lab and pond studies. In addition bacterial ABUNDANCE was similar in treatment and non-treatment ponds. He concluded scientific evidence and logic also do not support use of bacterial amendments as a means of improving water quality in ponds. My studies and experience tend to agree with Dr.Boyd's conclusions. The main exception I have found is bacterial amendments are useful in ponds that have been routinely treated with algaecides and herbicides that damage and degrade the bacteria community. Amendments could help reestablish and 'kick start' normal healthy bacterial communities in compromised waters.
My "take" on these amendments is none of these products will state what is in the product. IMO this is primarily because almost all or all of them are just using natural bacteria cultures that are known natural decomposers that naturally occur in uncompromised habitats / ponds /lakes where the bacteria species originated to create the cultured products. Thus in natural healthy environments nature has all the necessary bacterial species present to keep it healthy and functioning as it has for eons prior. Human activities can damage these natural bacterial communities and sometimes seeding or recolonization may be necessary or beneficial.
Dr. Boyd has an excellent water quality book recently published and all serious pond managers should have and thoroughly understand this easy to read book. Ignoring it is negligent. Ask your pond manager if he has Dr. Boyd's book: Handbook for Aquaculture Water Quality. His answer may provide some insight into the background and water quality knowledge about his advice. I also have one of DrBoyd's earlier more technical books titled Water Quality in Ponds for Aquaculture (1990).
Technically running the aerator placed on the bottom in winter also destratifies the pond, but instead of making the pond warmer on the bottom it makes the bottom colder by mixing coldest surface atmosphere exposed cooled water toward the bottom that normally remains 4C during winter. I have measured winter bottom aerated water temps down to 33F, 6 degrees colder than 39F. This colder temp than 39F(4C) toward 32F(0C) does little harm to the trout as it would to other warm water fish such as bass and catfish. You could experiment with moving the diffuser closer to the surface to test which depth produces the quickest and largest open water area if you decide to run the compressor fewer hours per day to just daily create a zone of ice free water and allow light penetration. As long as the ice free area freezes with clear snow free ice,,,, light will readily penetrate the water in this clear ice area and open water is not really needed until the area again becomes snow covered.
