DyoFix Pond Black Dye 300g

A black pond dye for smaller garden ponds and fountains that helps keep the water free of algae by blocking the light it needs to grow, leaving a dark, mirror-like surface instead of green water. It's gentle enough to leave pond plants and filters unaffected, and reduces how often you need to dose again since one application keeps working for months.

DyoFix Pond Black is a liquid pond dye that turns the water black by absorbing and blocking all daylight before it reaches below the surface, rather than simply tinting the water a shade of blue or green like many pond treatments.

Overview It suits smaller garden ponds and fountains where a dramatic, mirror-like finish is the goal. By cutting off the light algae needs to grow, it helps keep the water surface clearer of green growth through the dosing period. Leaves and flowers sitting above the waterline are left unaffected, and fish remain safe in the treated water, though you won't be able to see them once the dye takes hold.

Each pack contains one 300g bottle of concentrated black pond dye, ready to pour directly into your pond.

Key benefits The dye starves algae of the light it needs by stopping it passing through the water, so it works on the cause of green pond water rather than just the symptoms. It also gives the surface a reflective, obsidian-like finish that holds up under sunlight, moonlight or candlelight, turning the pond into more of a feature than plain water. It contains no pesticides or herbicides and won't harm your filter system or pond plants, so you can treat the water without worrying about knock-on damage elsewhere in the pond.

Choosing your size One bottle is dosed for ponds up to a set volume (see the sizing guidance below), so measure or estimate your pond's total water volume before ordering and buy enough bottles to cover it. A single application keeps working for months rather than days, which cuts down on how often you need to dose again.