Bactoplus Fresh PSB (Photo Synthetic Bacteria)Living PSB for superior water quality. £24 2,000ml will dose 5 x 40,000 litres of pond water. with beneficial bacteria Unique living PSB bacteria is cultured in the Netherlands, Fresh PSB (beneficial Bacteria) is active immediately and as soon as it has been added to your Koi pond. It improves water quality and clarity by removing ammonia and other impurities from the pond water. As the PSB bacteria does not consume any oxygen in the process of removing ammonia, it can be used in very high dosage levels. Photo Synthetic Bacteria are capable of absorbing large quantities of organic waste, and hence will improve the water quality resulting in a better environment for your fish. Bacteria in for example filter starter (gel) and BSO use oxygen, Photo Synthetic Bacteria on the other hand use light and because of this there is no competition with the bacteria in your filter. PSB can be used in large quantities. The PSB is produced in our own facilities and is packed undiluted. The red colour of Bactoplus PSB is the natural colour, no colourants are added to the product. The carotene produced by the bacteria is giving their red colour. The carotene is needed to absorb light. The presence of natural carotene in the product makes it also suitable as an addition to fish food, when absorbed by the fish the carotene will improve their colours.