Reduce invasive species Crassula Helmsii with C Special

Dyofix C Special was developed to control severe aquatic weeds; specifically for trials to combat the the growth of the non native, invasive species Crassula Helmsii.

Other novel methods of controlling the growth were carried out over a few years but none of these, including C Special, succeeded in eradicating the problem, but a reduction in the growth was registered.

During the Crassula testing period C Special was supplied for use in lakes with weeds that are less light dependent than most giving results in line with our other products and is firmly established within the range. Water treated with C Special takes on a slightly darker shade of blue and filters out greater amounts of red light.

Control severe aquatic weeds with Special C

Designed to control severe aquatic weeds

As C Special is designed to control severe aquatic weeds it has also been used to slow down or halt the growth of Chara, an algae that has the appearance of a weed.

Just 1 Kg will treat 4 million litres

DyoFix C Special is generally only used in larger lakes so we have packaged it in 250gm water soluble sachets – this size of pack makes the usage calculation easier as 1 sachet is used for every million litres of water to be treated.

C Special is supplied in 1 Kg boxes.


C Special pond dye

DyoFix C Special Powder

£36.00 £43.20 incl. Vat

1kg dissolvable sachets | Treats 4,000,000 Litres

Note: See calculator below if you are unsure the quantity you require for your lake.


C Special is eco-friendly

Free from herbicides, pesticides and algaecides, the lake dye will prevent an excess of nitrogen which (if unchecked) can result in an algal bloom where algae reproduce in record numbers. Algal blooms are known to be harmful to other pond life, both other plants and fish. With C Special you are left with a wild-life friendly, natural looking pond for you and your family to enjoy.

Safe for children, pets, fish and pond life


Calculate the volume of water in your pond using the calculator below.

C Special Powder Sachets

By supplying powders in 250gm water soluble sachets it is easy to calculate the number required to dose a lake or pond. In large lakes, if a boat is being used, simply drop sachets in different areas where they will dissolve releasing the C Special. By spreading the area, the time taken for the C Special to fully mix with the water is reduced.

Using sachets where a boat is not available. Facing the water with a breeze coming from behind, drop a few sachets along the edge and throw the others into the water. The breeze will move the water and C Special will dissolve and mix in quite freely. C Special will fully mix with all of the water using this method but may take a little longer.

Top Ups

To maintain the level of DyoFix in the water, as a general guide, add 10% of the original dose monthly.

The first application should be made in early Spring.

Reference Samples

If reference samples are desired, it is suggested that these should be taken at least a week after the initial application. Samples should be in clear containers with a secure lid, labelled with the date and location and stored in a dark place. An initial comparison to tap water will show the amount of colour present in the water.


How much C Special should I order?

Metres Calculator