Print This Article
Pond algae are pretty easy to control. If you have koi, you must have an extensive filtration system to control algae. If you
have goldfish and feed them, you must have filtration, but you can control algae. If you do not feed your goldfish and do
balance your pond, algae rarely grow at all.
When sun hits water, algae grow. That is the way of nature. In order to break that cycle, there are things you can do easily
to keep your pond water clear and healthy. Most of the following suggestions are germane only if you have goldfish and do not
feed them. I have included a few for you goldfish feeders who simply cannot help yourselves.
- Balance your pond ecologically. Use bog plants like irises or umbrella plants. You must have oxygenators or submerged
plants. The best is anacharis, followed by cabomba and hornwort. You must have one bunch of these submerged plants per
square foot of pond surface. These plants arrive with a rubber band holding them together. Remove the rubber band before
you put the plants in your pond. If you donít want them floating freely, you may pot them up in several pots that sit on
the bottom of your pond. The submerged plants are fertilized by fish waste and CO2, a fish byproduct. The fish eat the
submerged plants, but they grow faster they the fish can eat them. Nice cycle, huh? Nature takes care of itself if we can j
ust leave her alone. If you have too many fish, they will eat all your submerged plants and you have to start over again.
A good rule for fish load is 1 linear foot of fish per 25 square feet of pond surface area; tails donít count. If your pond
gets green, have patience. It will fix itself
- When pH gets on the basic side algae flourishes. Vinegar is weak and it takes forever (days) to neutralize. But it takes
an expert to use muriatic acid properly, so do not put concentrated muriatic acid in your pond to balance pH unless you know
what you are doing. You can buy commercial products, usually called pH down or some such. They are expensive, but work well.
- It is good to have algae slime on the sides of your pond... this is a sign of a healthy pond and can generate up to 70%
of the oxygen needed for your pond.
- If you feed your fish, these simple ways of keeping your pond clear will not work. You will need a filter, preferably a
- You must cover at least one half the top of the pond with floating plants. Parrotsí feather is great, as are water
hyacinths, water lettuce and water lilies. If you live in the tropics, you can have beautiful tropical water lilies. You
must be willing to either sacrifice them in the winter or store them away until warmer weather arrives again in the spring.
- Scotch Barley bales work, but the pond must be cleared of algae first and it takes some time to work, sometimes up to a
month. Always put another barley bale in your pond before the last one is gone.
- Black dye works really well in a formal or reflecting pond. The black water sets off the water lilies and they look
wonderful. Anacharis can live in the black water. Do not use the blue or green dyes. Trust me they are ugly.
- There are several products on the market that will wipe out algae population without harming fish or desirable plants.
The downside is they kill all the algae. It clumps up in the bottom of the pond. This can cause oxygen depletion and your
pond can become anaerobic. I never use any chemicals to kill algae. There is too much chance that other living things will
also die. Being an organic gardener, I use nothing that has Ďcide in the name. I will not introduce any poisons into our
soil or water. We have too many already.
- Change 25 or 30% of your pond water weekly. Pump it into your veggie or flower beds. They will thank you. When you refill
the pond, donít forget the dechlor.
- UV lights will work and are good when you have too many fish. They can also kill many beneficial bacteria and you are back
to your anaerobic pond. Using plants to keep your pond clear and clean is certainly the easiest and best way. And it needs