I have 3 large metal stock tanks. Over the years I have never had any problems with string algae until last summer. My oldest stock tank that is over 20 years old started growing lots of string algae. That sort of surprised me since it had never happened before? I have often wondered if the zinc in the metal prevented the growth of the string algae in some way? Neither of my other stock tanks had a problem with algae at all. However, I have changed this older tank somewhat. A couple of years back, it developed some small holes in the bottom of it. So I painted the bottom with swamp cooler tar, completely covering the metal. So a lot of the surface metal was covered over and there was less zinc to get into the water. Now I don't know if it was the zinc or not, but something is preventing the algae grow in the two newer stock tanks. Have any of you that have metal stock tanks noticed not having a problem with string algae or do you have a problem with it?

Water hyacinth is great at filtering out sediment if the water flows through the feather like roots. Hyacinth is also great at absorbing excess nutrients thereby reducing the food-source for the green algae. The problem with Hyacinth is that it is a tropical plant and doesn't grow well until the water is warm. The green suspended algae bloom will take place as soon as the ice thaws in early spring. The best plants to help in the cold climates are the very early growers, I like marsh marigold, it sprouts earlier than any others I've found and gives my garden an early burst of color. Barley bails control string algae which is a problem later in the spring. I add a barley bail shortly after the thaw and hide it under the marsh marigold leaves. Like I said, no algae problems in years.

I just started a 7x7 koi pond with three levels. I thought all I needed was the liner, and a pump with a fountain. I eventually got some plants, but I couldn't find pond plants. Luckily I looked on line and knew what to look for. The nurseries I went to didn't have "pond plants", but I noticed they had the plants I needed listed under "tropical plants". I found a few aquatic plants from the pet store. I have 3 koi and 2 goldfish so far. But a week after setting up my pond it turned into pea soup. After trying out different products on the shelf and nothing seem to be getting better, I looked up different pumps and filters. The biological filters were so expensive, so I checked out how they were made and had my husband help me make one ourselves instead. I think it's prettier, and heavier duty. The fountain sucks up the water and shoots up at the top so you can see the water above the vase (which was green but has gotten really lighter..lol), then it falls back into the vase met by a layer of those barley squares, a two inch thick wide webbed filter, then another thick tight webbed filter, and at the bottom of the vase are bags of charcoal filter rocks. There is a contrast between the green water shooting up at the top, and the clear water spitting out from the bottom of the vase. The pond so far is getting cleaner every day. I am just waiting for it to get clearer like it was when we first started the pond. Luckily I didn't give up and kept trying, or I wouldn't have come up with that convenient and money saving idea. I would love to hear more about money saving ideas. Or if there is anything else I am missing in my vase to filter. Oh, I also added a scoop of that enzyme powder with algae. I think that is everything other than getting a UV light filter. Any suggestions or tips that won't harm my plants or my fish?

Waterbug_guy, I decided years ago that I prefer the KISS method to water gardening, which is when I put away the salt and testing kits. I decided not to fight the natural water conditions I had, although way back then there all kinds of people telling me to do something immediately to drop my pH which they felt was too high, add salt, and test daily at least. I decided that was not what I wanted, and my fish and I have been content with that decision for about a decade. So I certainly agree with a lot of what you have said. You are also certainly more knowledgeable than I about how much the actions I took could have altered my test results. I can not rule out user error because no matter how simple the test I am simply cable of erring. But my initial thought WAS that my ammonia had been high and the filter was kicking in and taking care of it, and the water change and plants helped. But I am not disregarding what you said, because I am just not as up on testing and treating those results, in part because I chose not to g0 that route years ago. Like I said, it really doesn't seem very important any more. But I am going to continue testing at least a few times a week for a while and will try to remember to do it right before and after cleaning the filter. I would be interested to see what the results are before starting the filtering next spring with the fish load I have, as well as from the time I start filtering until the WH take off again next year. I wonder if I am having periods of high ammonia levels before the bio filter really gets going again, when I only have a few small WH. Something to maybe keep an eye on in the fall once a frost has starting the kill the WH, as well. Especially once I put the filter away for winter. Joecd, as far I am concerned any filter that harbors the good bacteria that can change the ammonia in the pond to nitrite and then nitrate is a type of bio filter. There are almost as many ways of doing that, it seems, as there are people with ponds. One way is to purchase a canister type filter that has media inside for these bacteria to grow on, as I did. There are also many types of homemade biofilters, and most surfaces in your pond probably do that to some extent, as a well. But most people I have heard referring to a biofilter are referring to a separate filter that is specifically designed to do that, whether it is a purchased filter or a homemade one, rather than to the natural bacteria on the surfaces in the pond.