Koi Medications » Virkon S Aquatic
Virkon S Aquatic Tablets
The Virkon S Aquatic Tablets can be used and repeated weekly as a conditioner for pond water. VERY effective in lowering the bacterial count in a pond.
Used to Sanitize Koi ponds
What Is it exactly:
Koi Herpes Virus and Carp Rhabdovirus are serious threats to Koi keepers. Many fish are carriers without showing any signs. When placed in contact with vulnerable fish, they may, especially if stressed, excrete virus into the water and this leads to infections and very high mortalities.
Virkon S Aquatic® is the most proven of all fish disinfectants. In addition recent work has shown that if added to the water of fish farms on a continuous basis at low enough levels to present no toxic threat, it still sanitizes the water. This does not disinfect the water completely, like the concentrated disinfectant but sanitizes it and so reduces virus availability for infection.
Studies with Koi carp in the USA have shown that the use of Virkon Aquatic® in carp water at up to 10 parts per million (ppm) on a continuous basis is quite safe and highly effective against all Herpes viruses.
Unlike farmed fish, Koi are kept in recirculation systems with biological filters. This makes continuous dosing of the incoming water impossible. Koi Herpes Virus is however potentially such a severe problem that Dupont Animal Health Solutions in conjunction with Bradan Biosecurity have developed a system which will normally still provide a degree of water sanitization for the Koi owner without rendering filters ineffective or causing a concentration to rise to toxic levels.
Virkon is primarily a powerful virucidal disinfectant for disinfecting equipment. It has now been used safely for in-water sanitization against Koi Herpes Virus and Carp Rhabdovirus, at up to 10ppm, in many hundreds of koi systems in Europe and USA. Because all koi filter and pond systems and water chemistries are different, however, this leaflet can only be issued on an advisory basis.
Sanitizing Koi Pond Water
Most Koi tanks and ponds are fitted with a recirculation pump, microbiological filter and a UV light source. As the sanitizing Virkon Aquatic� is deactivated by UV it is essential that the UV source is fitted just before the point of disinfectant addition.
Provided there is no evidence of any illness in the fish, for normal sanitization, the tablets should be added at the rate of 5 grams per 5000 litres of water. (One tablet per 1000gallons of water).
NEVER add the tablets direct to the pond.
Add the required number of tablets to 10 litres of fresh water and allow the effervescent tablets to fully dissolve.
Once fully dissolved, add the water into a skimmer or settlement tank so that it can be gradually added to the pond water as it is filtered. A dosing system is easily made from a plastic bucket with a small hole in it to release the Virkon Aquatic® slowly.
Ensure the recirculating pump is running to aid dispersion of the disinfectant.
Dose once per week. Dosing can be increased to twice per week during the main KHV risk periods in spring and autumn. At the point of weekly redosing it is important that 5% of the water volume be discarded and replaced with fresh dechlorinated water eg for a 1000 litre tank remove 50 litres. The Tablets contain a small amount of a lipophilic surfactant, specifically active against the external envelope of viruses such as Koi Herpes Virus and this can build up over time to produce foams if such water changes are not made
All new fish should be held in isolation in a freshly washed and disinfected tank and filter system prior to introduction to the main pond. (The empty tank and pipework should have been sprayed and pumped through with Dupont Biosolve® detergent, a specially formulated virkon compatible detergent, left for 30 minutes, rinsed with chlorinated water, sprayed with Virkon at the disinfectant rate of one tablet in one litre of water, left for a further 30 minutes and rinsed again with chlorinated water).
In the isolation tank, water should be treated with two tablets per 1000 gallons every three days. Fish should be closely observed while in the isolation tank for up to three weeks and fish only transferred to the main stock when the owner is satisfied they are in good health. The isolation tank water should then be emptied and the tank disinfected again
Suspected Disease Conditions:
Where there is a suspicion of Koi Herpes Virus infection or Spring Viraemia Virus* infection, obviously affected fish should be immediately removed, killed, placed in solution at one tablet per litre and disposed of.
The water of the remaining healthy fish should be immediately sanitized at a level of 4 tablets per 1000gallons (one tablet per 1250 litres) and this should be repeated daily for at least a week. At this sanitization level it is essential that at least 10% of the water is renewed weekly.
Great care is necessary not to stress the fish in any way. If these fish appear to remain healthy then water sanitization can be reduced both in level and frequency. Any obviously sick fish should however be removed as above.
REMEMBER Virkon Aquatic® does not treat fish. It sanitizes the water in order to reduce the infectious virus levels in the water. There is NO Point in trying to bath treat fish with the tablets
Effects on Filters:
By its nature, this product is a bactericidal and will have some effect on Koi filters. However, provided at routine maintenance each week, 5-10% of pond water is replaced before redosing, this should not materially affect filter effectiveness. If using at higher doses or more frequently, slight foaming may develop. This is not dangerous and the lipophilic surfactant which causes it is essential as part of the anti viral activity. If foaming does occur a lower dose may be applied accompanied by increased water changes until the water ceases to foam.
Koi users have found that a good indicator of being used at the appropriate level is that the water in the pond takes on a clean and slightly crystalline appearance. This can be a useful guide but this effect will not necessarily occur with all water and pond chemistries. Unfortunately, at the very low concentrations of recommended, it has not proved possible to devise an accurate test kit for measurement of levels in water, but work on this is continuing.