The company had previously forecast 2020 revenues of between $50 million and $70 million.
It is a substantial reduction over their previous forecast range, if achieved it would result in a sales increase of approximately 40 per cent, at the midpoint, over last year.
The move is due to new outbreaks of Covid-19 in several countries but particularly in China and the US.
Shares in Phoslock Environment Technologies (ASX:PET) are trading 15.4 per cent lower at 39 cents.