HELP MY POND IS GREEN!
It is so frustrating to do all that work to get a pond set up, and then you can't see your fish. Let me try to help!
Step one, RELAX. Although it looks bad, green water is actually healthy for you Koi, so take a deep breath and know that while you are working out how to get to see them again, they are enjoying themselves in that nice green bath they are in.
The only way to have clear water is to find that natural balance where nutrients are cycled correctly, that the levels are kept low, and the other factors that create green water are addressed. Chemicals are not the answer, but they can help you get to where you need to be. But first lets take a look a the root causes of green water.
Factor Number One: SUNLIGHT. Algae just loves lots and lots of it. So think about ways to provide shade for your pond. There are pretty sunshades out there that you can buy, or you can get creative with a tarp, a pergola, plant a shade tree, anything. Just know that if you find a way to reduce the sunlight exposure, not completely but at least to just the early morning or late evening hours, you are making a great move towards solving this problem.
Factor Number Two: NUTRIENTS
When Koi and goldfish breath through their gills, they excrete Ammonia. They also poo, and that waste is just plain wonderful fertilizer for Algae.
Ok, here is where I get on my soapbox and tell you that if you own a koi pond you should also own a water test kit. You want one that checks the following: Ammonia, Nitrites, Nitrates, PH at the very least. Test for all of the above and know what your parameters are. Nitrates are what algae and plants use to grow and thrive, so if you get a handle on your nutrients, you can get a handle on your green water.
More on how to do that later, but if you are experiencing a great big green bloom right now, you might want to stop feeding your fish for a few days. Stopping the input of all that fertilizer will help you get a handle on the situation.
Facter Number Three: BACTERIA.
Bacteria play a huge role in your pond. If you have a healthy and thriving population of "beneficial bacteria", they will break down the Ammonia (which is VERY toxic, by the way - - I think it is the leading killer of koi in small ponds), into Nitrites, and that is further broken down by different bacteria into Nitrates.
You need to get yourself a good biological filter. Google "bakki filter", you can make your own or buy one. There are many many choices out there right now. youtube is full of them. Search on Ebay, Craigslist and Amazon. A biological filter is one that has "media" in it. Media is the HOME for your bacteria. The media can be made of plastic balls, "bio-balls", matting, lava rocks, anything that has pores, really, and the bacteria move in and set up shop and start doing their thing. It can take up to six weeks to establish a filter with your own fish, or you can give things a boost by adding them from a convenient bottle (See Ammonia Fix - that was our first product!)
So you WANT the bacteria to break down dangerous ammonia and wastes into nitrates, but you need to REMOVE nitrates as well. How to do this?
1) WATER CHANGES. WATER CHANGES. WATER CHANGES!!! I said that three times because if you do nothing else, this is probably the single most effective thing that you can do to keep algae under control. You should strive to "flush the toilet" at LEAST once a week. This is the simplest and most convenient way to reduct your nutrients. The least I would aim for is 10%.
Ok here is another soap box opinion: The BEST way to do this is to have a CONSTANT trickle going into your pond. Put a pump or hose on your water source, measure how much water is going in, and adjust the flow for what you are looking for. Direct the outflow to your lawn or garden (Aquaponics guys have been using fish for years to fertilize their crops) and let your grass or vegetables benefit from all those good nutrients.
2) WATER PLANTS. Water plants such as water hyacinth, water lettuce, water lillies, cattails, etc. all of them uptake nutrients. They compete with the algae for the nutrients and are a good way to help "starve" the algae out of business. They also provide SHADE (see factor number one!!!) so its really something you should do.
Okay, now that you know what needs to be done, and once you have made arrangements to actually DO all of these things, now I can tell you about a two part kit, Koi Lady Clean and Clear Parts I & II, that will greatly accelerate the pond cleanup process.