Click above to go to Algae control products
Algae can be quite the nuisance but it also is part of a healthy pond. Often algae is helping to filter the pond as it consumes fish waste. Your water may test perfect during an algae bloom because the algae is acting as a "bio-filter". During the day algae will make oxygen. However, at night algae will consume oxygen. So if you have an algae bloom be sure your pond has adequate aeration 24 hours a day and expecially at night. Algae can be ge helpful but in excess it can clog filters and pumps.
There are two types of algae; green water and filamentous algae.
GREEN WATER is a single cell microscopic algae which can bloom very quickly and turns the pond completely like pea soup. It can be green or brown in color. You will not be able to see clearly to the bottom of the pond. If it is very thick you will not even be able to see 3 inches. Green water is very common in new ponds. It is also very common in ponds that have inadequate filtration. When the pond is new or underfiltered the green water will bloom to eat the available nutrients in the pond. As your pond ages and more bacteria and / or aquatic plants will have had time to develop and these will eventually compete with the green water for nutrients giving way to clear water. Aquatic plants can help to clear green water but you will need a lot of plants. You must have at least enough plants to cover between 10% to 50% of your pond surface. These plants will take time to establish. If you have a lot of large koi they might eat the plants and could prove frustrating. Your first approach to controlling green water should be to improve your filtration. Your filter should be large enough to handle the build up of solid waste and also be of sufficient size to grow a large colony of beneficial bacteria. Install as large a filter as possible. You will really appreciate having an ultraviolet clarifier as a permanent part of your filter system. The UV Clarifier will drastically improve water clarity. However, you must size the unit correctly to match the gallons of the pond and the water flow rate of the pump and filter. Try to pass the entire pond volume through the UV and filter one time per hour minimum. Check with the manufacturers suggested flow rates to be sure of purchasing the right unit. The UV will not work very well without a filter. As the UV kills the algae, the filter must capture the floating particles to ensure clarity.
Green Water can also be controlled with certain chemicals. All chemicals must be used cautiously. You must know the gallons of your pond accurately. All chemicals will work better if you have a good filter system.
Try Microbe-Lift PL bacteria for natural algae control. This photosynthetic bacteria grows right in the water and competes with green water for nutrients, thereby reducing the algae growth and giving way to clear water. This is a very popular product because it is natural and will not hurt plants or fish and it works.
Other bacteria based products which work are Super Bugs liquid or powder which can also give good clarity.
Clarifiers like Pond Care "Accu-Clear" and Tetra "Water Clarifier" are very safe and act as a flocculant. These chemicals are easy to dose and will turn the microscopic green water into larger particles which can settle out or get trapped in the filter. They also act as a filter aid. These flocculants will make your filter media more sticky so it can trap small dirt better. Especially useful for new ponds. We highly recommend either of these two products to give you much faster clarity and are safe to use with any other product as well. Clarifiers are best used early in the morning. Use a dose based on the degree of clarity in the pond. For example if you can only see half way down then use a half dose. If you can see almost 3/4 to the bottom then only use a 1/4 dose. Use a full dose for a pond that is totally green. You wil have to use more than one dose in most cases. Dose daily according to degree of clarity. You will see a gradual clearing so be persistent. If you have a good filter system you can have overnight clarity in some cases.
HAIR ALGAE or filamentous algae also called strign algae can really overtake a pond in early springtime. Often the water will be crystal clear when you have a nice growth of hair algae. It actually competes with green water for the food sources in the pond. So Hair Algae actually acts like a filter for your pond. It is growing because there is an abundance of nutrients available. Your biofilter may be too small. Your biofilter may be too clean or you may have damaged the good bacteria with overuse of antibiotics or parasite medicines. Your biofilter might just be too cold to function. So the hair algae makes up for lack of proper filtration. You may live in an area that experiences freezing winters and every year your biofilter shuts down. The hair algae will act as a very nice filter consuming the fishes waste and keeping the water clear until the biofilter kicks in again after it warms up. So before killing your hair algae, consider what it may be doing good for you and the fish. Killing mass quantities of hair algae in your pond will most likely kill your fish too, due to the low Oxygen levels that will follow with all the dead algae. Besides the hair algae could be your main filter in the pond. Killing it will just result in elevated ammonia and nitrite levels which will damage your fish. If this is the case it may be better to just manually remove the hair algae every week until your filter starts to function. You can slow it down with natural chemicals like Barley Straw or Barley Straw Extract. The lignins in Barley straw help slow down the growth of hair algae without killing it completely. NO harm to aquatic plants. You will have to be persistent with dosing however. You may also slow down hair algae with certain bacterial products like Kusuri's "ECO-BOOST" This natural bacteria loves to eat the same nutrients as the hair algae so will compete and help reduce hair algae naturally. Another fine product is Interpets "Pond Balance". It binds up calcium in the water which is a major nutrient needed by the hair algae for it's fibers. This product has been around for a long time and a lot of hobbyists use it. No harm to aquatic plants or fish.
Another chemical alternative to hair algae is PondCare "AlgaeFix" or Tetra "Algae Control". Both are the same chemical. This will definitley kill you hair algae and give very fast control. So be sure to remove most of the algae first by hand so that you don't kill off a a big mass of algae all at once. It is better to use this product as a preventive treatment before you have a lot of hair algae. You will have to dose at least 3 times for the first week and every week after that. We don't recommend this product to kill green water. If you use it to kill green water you likely have dead fish due to the low oxygen levels that will occur due to the decomposing dead algae. Use a clarifier flocculat first for green water and then use the AlgaeFix or Algae Control to prevent it from growing back.
We have use Water Blocks and Pond Blocks for 22 years as a slow time release algaecide that functions best as a priventive treatment. These blocks slowly dissolve on the bottom of the pond and release small quantitiews of algaecide that does not hurt the fish and only has an impact on aquatic plants like the floaters hyacinths, lettuce and duck weed. Most other aquatic plants can tolerate the blocks. Our pond service team uses blocks on all our monthly service accounts because they work and are very easy to maintain in the pond. Just replenish as the blocks dissolve.. They usually last about 6 weeks. If they do not dissolve then place in an area of faster water flow. In fact you can use a double dose for your first dose. Place half the blocks in an area of fast moving water so they dissolve quickly and place the other half on the bottom of the pond to act as a slow dissolving buffer. After the first month just replace the bottom blocks only for a very clean and clear pond with little effort. Just stay ahead of the game. We do offer these blocks in singles or in a bag of 25 for a nice discount. Believe me you will like the blocks once you have been persistent with them.