Frequently Asked Questions about VirescoTM Aqua and VirescoTM Koi What are the benefits of using VirescoTM in ponds? VirescoTM Aqua will give three basic benefits to the pond keeper. It will reduce and remove nutrients (nitrate and phosphate) in the pond water that feed algae. As a result, blanketweed (string algae) and algae bloom (green water) die of starvation. Secondly, VirescoTM Aqua will digest waste organic matter in the pond. Thirdly, VirescoTM Aqua will improve the health, growth and disease resistance of fish.

What is the difference between Viresco^TM Aqua, Viresco^TM Koi and Viresco^TM Digester?
Viresco^TM Aqua, the original product, is a 50:50 mix of two groups of micro-organism based items. One group removes the nutrients - notably nitrate and phosphate - from pond water and the other group digests organic waste on the bottoms and sides of ponds. Viresco^TM Koi is a microbial product that contains 100% of the nutrient remover. Viresco^TM Digester contains 100% of the organic waste digester.

Should I use Viresco^TM Aqua or Viresco^TM Koi to remove blanketweed and algae bloom?
Where ponds have little or no organic waste, then the waste digester part of Viresco^TM Aqua is somewhat superfluous. Our recommendation, therefore, is to use Viresco^TM Koi. For all general garden ponds in which organic waste arises from fish excrement, from surplus food or from wind carried leaves and grasses, we recommend Viresco^TM Aqua. If in doubt then use Viresco^TM Aqua.

How is Viresco^TM applied?
Viresco^TM is a dry powder. We advise that the appropriate amount be mixed into water and allowed to stand for a few hours. The water should be taken from the pond. Ideally it should be mixed in the morning and applied to the pond in the evening. Also some air should be introduced into the solution via the use of an air stone or regular whisking. Never leave the solution for more than 24 hours before applying to the pond.

Should Viresco^TM be put into the pond or into the filter?
Most people put the solution of Viresco directly into the pond although some put the concentrated solution directly into the filter.

How frequently should Viresco^TM be used and how long does it last in the pond?
Some of our customers make one application and then see no more blanketweed for over one full year. Others keep blanketweed at bay for a few months with one application. However, a minority of pondkeepers need more than one dose to suppress blanketweed. Remember, every pond is different.

Should the pondkeeper apply maintenance doses of Viresco^TM?
It makes sense to consider the application of maintenance doses. However, unlike recommendations for some other products, we do not suggest what and when these should be. We advise that nitrate levels should be regularly checked and the readings used as a guide as to when more Viresco^TM should be added.

What difference do fish stocking levels and overfeeding make?
Many ponds have filters with capacities that are far greater than those needed for the ponds' volume. More fish tend to be introduced knowing that the filters can cope with the increased amounts of ammonia. Where this is the case, then more Viresco^TM than our suggested dose should be used. The amount required is linked to the increased amounts of ammonia produced rather than just straight water volume. As a yardstick, if more than 60 inches of fish are in 1000 gallons of pondwater, more Viresco^TM should be added.

Similarly, where overfeeding occurs or when very high protein foods are use, more ammonia is produced. More ammonia means more nitrite and more nitrate. More Viresco^TM should be used.

How quickly does Viresco^TM work?
Many people see blanketweed dying back within 4 to 5 days. For others it does take longer. For most people it occurs within about 3 weeks. If, after this time, no noticeable change has taken place, then apply a second dose.

What happens as the Viresco^TM starts to work?
The colour of the blanketweed starts to change from green towards brown. It also becomes brittle and pieces break off. Some people have reported that pH levels in the pondwater increase as the blanketweed dies.

Should the blanketweed be removed before applying Viresco^TM?
We would advise that as much of the blanketweed as possible should be wound out before the Viresco^TM is applied. This will reduce the need to clean up weed debris after it has died. It will also keep better control over rising pH levels.

Is Viresco^TM safe for fish?
Yes, Viresco^TM is safe for fish. It was initially formulated for use in commercial fish farming to improve the growth, health and disease resistance of the fish. The fact that it suppressed algae growth by removing the nutrients on which algae feed turned out to be a bonus.

How does Viresco^TM improve the health and disease resistance of the fish?
The reason why a fish succumbs to a bacterial or fungal disease is the bacteria or fungi that form the disease have become predominant. If the pond system were kept in better balance and the disease microbes had greater competition, then they would not become predominant and form the disease. The micro-organisms in Viresco^TM are present in huge numbers and in a number of different species. They do not remove the disease forming species but compete with them for food and space and keep their numbers down so they do not take over.

What does Viresco^TM do to aeromonas?
Aeromonas bacteria, which can cause severe problems to the health of fish, particularly in koi ponds, is kept at bay in the same way as other pathogenic microbes by the competitive action of the micro-organisms in Viresco.

Is Viresco^TM safe for other wildlife?
Yes, there is no problem for other wildlife, eg newts and frogs.

Does Viresco^TM harm plants?
No, Viresco^TM does no harm to plants. However, because Viresco reduces nitrate levels in the water, plants may grow less strongly. For example, leaves of, say, water lilies grow less vigorously but the bonus is that they should flower better.

Are the Viresco^TM products chemicals?
The Viresco^TM products are micro-organism based and the method of operation is biological and not chemical. Viresco^TM contains a number of species of micro-organism carried on bran. In addition there are support nutrients which are included in the mixes. One critic on a website chat page suggested that, because Viresco^TM worked so well, it could only be a chemical and not a biological/microbial product! We corrected him!

What about the use of salt in koi ponds?
There is some evidence that using salt can inhibit the effect of Viresco. We have had reported by one customer that salt levels of over half an ounce per gallon can affect Viresco^TM. We remain unsure about this. as another pondkeeper stated that salt at this same level did not affect the Viresco^TM in her pond.

What about magnets?
Magnetic blanketweed control products do not affect the microbes in Viresco^TM.

Can I use Viresco^TM with chemicals?
Any fungicidal chemical that knocks back the microbes in a filter system will also knock back the microbes in our Viresco^TM products. Wait until these chemicals have dissipated. An example of such a chemical is potassium permanganate. However, other chemicals that are known not to affect microbes can be used at the same time as Viresco^TM Aqua. Many people use branded herbicides to remove blanketweed and these types of products would not normally lower the efficacy of Viresco^TM. However, it still would be best to leave a gap of a few days between using any injurious chemical and using Viresco.

How do water changes affect the efficacy of Viresco^TM?
Obviously as water is removed from a pond, the microbes in that water will be lost. However, because micro-organisms are always growing and multiplying as long as there is food and space available, those that remain in the pond will increase in numbers until a microbial balance is reached. One customer told us that he lost approximately 85% of his water shortly after applying Viresco^TM. Our product went on to clear his blanketweed.

What does Viresco^TM do to the micro-organisms in the filter?
Viresco^TM helps to maintain an efficient biological filter as it contains microbes that are used in the nitrifying process in the filter.

Is VirescoTM temperature dependent? Yes, VirescoTM works best in water temperatures above about 10°C (50°F). However, it will work in lower temperatures but more sluggishly. Can VirescoTM be overdosed? Yes, VirescoTM can be overdosed with no problem. It is organic, not chemical. We have one customer who each year uses 6 times our recommended dose all at once and for over three years has not seen any blanketweed. The only qualification is that enough oxygen should be present in the pond when VirescoTM is used."

What effect does Viresco^TM have on nitrate and phosphate?
Viresco^TM removes the nitrate arising from the biological filter. Nitrate is formed from the conversion of nitrite that in turn has been oxidised from ammonia. Nitrate can be reduced to zero within a few days and kept at zero by the action of the microbes in Viresco^TM. Phosphate is also reduced but usually much more slowly. When the nitrate level in the pondwater is zero or very, very low there is no food available for the algae - either blanketweed or algae bloom.

What about trials work using Viresco^TM?
Yes, in the summer of 2000 David Brown conducted a trial using Viresco^TM Koi in his 4000 gallon pond. David does research work and writes for the UK magazine, "Koi Ponds and Gardens". Prior to the trial, his pond had blanketweed growing at about 2 feet (about 60cm) per day and the nitrate and phosphate levels were 80ppm and 10ppm respectively. The trial started on June 26th. David applied one full dose of Viresco^TM to his pond and then took daily nitrate and phosphate readings. After 9 days the nitrate level had dropped to zero! The blanketweed by that time had died back and had stopped growing. In the same period of time, the phosphate level dropped from 10ppm to 5ppm. It continued to drop and bottomed at 1.5ppm after about 3 weeks. However, once the nitrate had reached zero, the phosphate level was not relevant to the growth of blanketweed. David produced a report for "Koi Ponds and Gardens". It was published in the September 2000 issue of the magazine. Over eight weeks after the trial started, nitrate was still zero and blanketweed was still absent.

In 2001, "Koi Ponds and Gardens" invited Brooksby College in Leicestershire to carry out a trial on six blanketweed control products. Two of these were electromagnetic (Pondweeder and Water King), one was the Aquastar which uses very small amounts of copper to remove the blanketweed, the fourth was Nishicare which dyes the water reducing photosynthesis and two were microbial (Kusuri Eco-Pure and Viresco^TM Koi). The results of the trial were featured in the August 2001 issue of "KP&G". Our Viresco^TM Koi product was declared the winner and given 4 stars. The other 5 products received only 2 and 3 stars!!

Do pH levels affect Viresco^TM?
We are finding that, in high pH water, Viresco^TM seems to take longer to work.

What is the effect of UV light and UV filters on Viresco^TM?
It is widely accepted that ultra violet light from the sky does destroy bacteria. In order to protect the bacteria in Viresco^TM, we recommend that the solution of the product be applied to the pond in the evening, during low daylight levels followed by a period of darkness. Initially, we also recommended that UV filters be turned off as the UV light from them could affect the efficacy of the product. However, we now believe that UV filters can be left on as the intensity of the emitted light is generally not enough to kill bacteria. A number of UV "experts" claim this to be the case. In support of this, David Brown who did the trials work mentioned above, did not switch off his UV light!

UV lights are primarily used to agglomerate algae bloom, the clumps of which are caught up in the physical filter. Viresco^TM removes the nutrients on which both blanketweed and algae bloom live, so there should be no need to use a UV filter once the nitrate levels have been taken to zero. One customer reported to us in July 2001, that he had started to use Viresco^TM Aqua more than 3 years previously. He had switched off his UV then and not put it back on again since!

It is still advisable to apply the product to the pond in the evening as the intensity of UV from daylight, even on bright cloudy is considerably greater than the UV from pond filters.

What is the shelf life of Viresco^TM?
The Viresco^TM microbial products are purposely put out as soluble powders. The Viresco^TM range, unlike microbial products in liquid form, have unlimited shelf lives if kept dry. There is a tendency for the powder to solidify over time. There is no problem with this. Liquid microbial products deteriorate over time. The end user of a liquid product is usually uncertain of its shelf life. Also, the end user might not know how long it has been in the supply chain since manufacture.

How much does it cost the pondkeeper to use Viresco^TM?
Using the best situation as an example, ie one application lasting more than one year, the cost for treating a 1000 gallon pond would be about 8p per week. This implies the purchase of a 3000 gallon pack for £12.25.

Using an example of a 1000 gallon pond requiring one full application along with maintenance doses of one quarter full rate every four weeks over half a year, the weekly cost is less than 18p. This is based on the purchase of a 6000 gallon pack at £20.75.

Unlike the recommendations for some other products, we do not specifically state that maintenance doses of exact amounts and frequencies should be used. Where products are mainly enzyme based, the enzymes run out and need to be replenished on a regular basis.