Question:
Well, we've just put a preformed pond in our backyard. It's not large, only 125 gallons (7'x5'x18"). We've had it up and running for about a month. We've added a water lilly and some Anacharis (3) and 4 small koi (5").

Here's my question, while the water is clear, it is very green. Research on the Internet has informed me that this is suspended algae. What I haven't  found is an answer as to how to get rid of it. Some suggest buying more plants which I'm going to do tonight. Is there anything else that would work? Are there any chemicals that can treat the water without harming plants and fish?

I appreciate your time.

Thanks.

I would be certain that I was running a biological filter and running it continuously. If you seed the pond and filter with nitrifying bacteria once a week you will find alot less algae, and silt. The culture I like to work with is Bacta-Pur Klear. They are good "bugs".

Thanks and I hope that this was helpful.

Answer:
Michael,

The best way to control the pea soup algae that you are having trouble with is by controlling the nutrients it needs to grow. Clarifiers typically just settle out the pond but don't control the real problem which are the nutrients that contribute to the fast growth of the algae in the first place.

Scenario Green water, add clarifier, pond settles out over night and is clear. 4 or 5 Days later pond returns to green state (cooler water this may take 10 days). More clarifier is added, pond settles out over night and is clear. 4 or 5 Days later pond returns to greener state. This is called nutrient cycling. The algae that is settled out dies and decomposes and releases nutrients for the next generation of algae, coupled with the nutrients added by the fish and foreign debris you have more nutrients to grow more algae (greener state). Then the filter has to be cleaned because its plugged up with silt and algae.

This was added as a tool to aid you in your assessment of your particular situation not as a means to aggravate you.

By selecting a pump and biological filter that are large enough to accommodate your pond you can step into the cycle and reduce the amount of nutrients that are in the water and thus reduce the algae to very acceptable levels. Adding a friendly nitrifying bacterial culture to the pond/filter is of great benefit. Bacto-Pur Klear is one culture that we work with here at the nursery and are very pleased with. I have the Bacto-Pur and biological filters available online. If you would like I can help to size your system for you.

If you would like a little help send the following information.

1. size of the pond measured in feet, all of these measurements should be in feet.

i.e. average length in feet. average width in feet. average depth in feet.

2. the size of the pump you are running and how often you are running it. Gallons per hour

3. the size and make of the bio filter you are running .

4. the amount of fish you have in the pond

5. how often you feed them and what you feed them.

6. do you fertilize the plants in the pond? How much and how often and with what?

Thanks and I hope that this was helpful,