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Viresco (UK) Ltd Tel: 44 (0)1845 525585 Fax: 44 (0)1845 523133

Viresco (UK) Limited is a company registered in England and Wales with company number 5079726 VAT No: 481 9223 35 © 2003-2012

Suppliers of speciality products for the amateur pondkeeper and gardener worldwide

Technical Information

Usage of the VirescoTM Aquatic Products

Viresco Aqua and Viresco Koi are available in 5g, 10g, and 25g packs. These will treat volumes of water as follows:

UK Gallons
US Gallons

Usually one application is enough to reduce the nitrate level to zero and maintain it at that level for a number of weeks or months. Many customers make one application and then are free from blanketweed for more than one year. Others require more than one application. The pondkeeper is advised to check nitrate levels on a regular basis, say, once or twice per week to see how the Viresco™ is reducing nitrate. Many people see nitrate moving to zero in less than a week: for others it takes a few weeks to reach zero. We suggest that, if little perceptible change is observed within, say, three weeks, another dose or part dose should be used. We would suggest that the pondkeeper considers the application of maintenance doses. However, we do not wish to recommend specific amounts at specific times. Our microbes do lose some of their viability over time as each generation of new ones succeeds the previous. It is therefore worthwhile using a nitrate test as an indicator of when more product might need to be applied.

However, every pond is different and each pondkeeper will do things differently. One customer decided to double dose with Viresco Koi to begin with and then to put in half a dose every two weeks. This turns out to be a successful method for him.

Application Procedures

It is recommended that the Viresco products are dissolved in a small amount of pondwater, left for a few hours and then bulked up with more pondwater before being added direct to the water in different places around the pond. Ideally the powder should be mixed in the morning, left with an airstone and introduced into the pond in the evening. Intermittent use of an egg whisk can be made if an airstone is not available.

It is important to keep the solution in a shaded place indoors. This is because the UV radiation from daylight could damage some of the bacteria in our products.

Water Temperatures

We state that our Viresco™ microbial based products work best in water with temperatures above 50°F or 10°C.  However, there is an advantage in having the Viresco™ microbes in the water at temperatures lower than this.  When fish are coming out of their cold-spell in late winter or early spring and start feeding again, their immune system is at its lowest.  This is when they are liable to pick up a fungal or bacterial disease.  Having the Viresco™ microbes in the water at that time, will tend to suppress any micro-organisms present in the water that might otherwise form a disease.

Above 10°C, the optimum working temperature for our microbes is between 30° to 33°C.  Temperatures above about 37° will kill the microbes.