(Note to any regular readers: This post may not be of much interest to you unless you have a pond. I’m posting it as a personal journal for keeping track of what I’m learning about pond care, and I’m making it public for the benefit of those folks who type things like “algae in my pond” into Google and end up here looking for information.
In this post I will mention specific companies and products by name; I received no compensation either in the form of money or free products from anyone. I have no affiliation with any company and only mention these products because they are the ones I am using; all product reviews expressed are my own, true opinions.)
We have a large earthen pond on the property that we bought last year. The pond is figure-eight shaped, about a third of an acre and six feet deep, and has diffusers in both “eights”:
It is stocked with Hybrid Bluegill, Largemouth Bass, Channel Catfish, Black Crappie, and Yellow Perch. It is also home to a large number of crayfish and frogs, plus a couple of turtles.
When we moved here in September of 2014, we had literally zero experience with or knowledge about caring for a stocked earthen pond. One of the best sources of information we’ve found is Stoney Creek Fisheries in Grant, Michigan, which is also a major pond equipment supplier. Grant is easily a three hour drive from where we live, so we don’t go there often, but they are very nice about taking phone calls and providing information.
When spring came, three things happened with our pond that concerned us: a lot of emergent weeds came up, the water turned cloudy with noticeable green algae build-up around the edges and mats of floating algae in the middle, and a strange smell almost like ammonia began to emanate from the pond on warm days. The water got so cloudy that we could hardly see the fish when they rose to the surface to be fed, as in this video:
The first thing we did is dye the pond with one gallon of Aquashade by dumping a half-gallon over each diffuser (pro tip: um, wear gloves if you don’t want your hands stained blue for the rest of the week – ask me how I learned this one 🙂 ). Pond dye is not a dangerous chemical; it is on the order of food coloring, and you can still eat the fish that come from a dyed pond. The purpose of dying the pond is to control algae and plant growth; the dyes are made up of blue and yellow colorants that absorb specific wavelengths of sunlight and prevent algae and plants from being able to engage in photosynthesis. Next time we dye the pond, in about a month, we will use only 1/2 a gallon.
The second thing we did was investigate what to do about the weeds. Manual removal with a rake is the best way if you don’t want to use chemicals, but this pond had been let go somewhat by the previous owner and manual removal was proving impossible (trust me, I spent many hours in the sun with a pond rake, pulling out weeds and muck until my shoulders ached). We realized that, despite our strong preference for organic maintenance, we were going to have to use a fish-safe herbicide to get some of the emergent plants under control.
After doing a lot of research, the product we chose was called Shore-Klear, which as far as I can understand is just a formulation of Round Up (glyphosate). According to the State, water in ponds treated with Shore-Klear is safe for swimming, safe for animals to drink, and does not harm the fish. To be extra cautious, my husband only treated half the pond, waited 48 hours, and then treated the other half of the pond so that wildlife and fish could move away from the treated areas. About a week later, some of the weeds are turning brown and dying and some are not. Possible reasons the product isn’t working great are user error (did we apply enough and in the right way) and a heavy weed infestation requiring multiple treatments to eliminate. We will spray again in another week and see how it does.
The next issue was the algae. The pond dye will help prevent algae growth but is not sufficient to eradicate a full algal bloom such as we had. The product we were sold by a local pond supplies business was Hydrothol 191. After researching this product carefully, we returned it to the store. We felt that this product, though not as dangerous to the environment as copper-based algaecides, still had too much risk for harming the fish, frogs, and other wildlife in our pond. Our bedroom window overlooks the pond and the frogs sing us to sleep every night; harming them would be unacceptable.
I spent hours online researching other products and finally selected GreenClean Pro (sodium carbonate peroxyhydrate). The USDA’s National Organic Standards Board lists this chemical as acceptable for use in the farming of organically-produced food crops. It does not harm fish, amphibians, or plants (unless you spill the undiluted dry product on the plants, in which case it can cause burns on them). If you look at the chemical name, you will realize that this is simply dried, undiluted hydrogen peroxide, the same as what you buy in the brown bottle at the store (only that is much-diluted).
My husband wore protective gear while applying it in order to avoid burns, but the minute it hits the water, it dilutes and thus does not harm wildlife. In order to not inadvertently burn frogs or turtles with undiluted product, my husband treated the pond in thirds and started out by running a rake around the area he was going to treat to encourage wildlife and fish to disperse.
Here is some algae prior to application:
Here is that same algae shortly (like an hour) after application:
The product foams just like hydrogen peroxide does when you use it at home. We used a skimmer net to remove large dead clumps of algae. What we couldn’t get will settle to the bottom. Notice the difference in water clarity two days after using GreenClean Pro – you can see lots of adorable catfish clear as can be:
We are very satisfied with this product; if environmentally-friendly pond maintenance is important to you, we highly recommend GreenClean Pro algaecide based on the results we’ve seen so far.
The next step will be dealing with the muck on the bottom of the pond, which is composed of organic material such as leaves, dead plants, dead algae, fish poo, and so on. The muck can build up very thick and smells yucky. A beneficial bacteria solution is used to digest the muck and improve water clarity; this gets rid of the ammonia smell we were noticing, which is generated by decaying material in the pond. We are using Pond Vive and Sludge Remover Pellets for this purpose, which we will apply later today. We decided to wait several days after applying the algaecide just in case it could possibly harm the beneficial bacteria. The gentleman from Stoney Creek told me that the bacteria in Pond Vive can digest 5-10 inches of muck per season! But we’ll see if the product actually lives up to that claim or not; I’ll report back in September on the state of our muck. 🙂
So, if you’ve clicked on any of the links above, you may have glanced at the price for these products. Horrifying, no? Would you like to know the grand total for what we spent on pond chemicals and solutions for this season?
Like I said, horrifying. The pond came with the property, and it is a really neat feature. We love the frogs, we love feeding the fish and will probably eventually even eat some of the fish. The kids kayak on the pond nearly every day, and it supports a lot of biodiversity on our property. And the price to put in a pond like this runs easily $10,000, so we wouldn’t consider filling it in. But I’m not sure we would have chosen to put one in ourselves, given the cost of maintaining them. Of course, if your pond isn’t near your house, you might not have to maintain it quite as much, since any pond odors won’t bother you, but ours is maybe 50 yards from our house.
If you have any experience with ponds or any questions for me about ours, let me know in the comments. I hope this informational is helpful!