well after finishing all the work and planting around my pond there was quite a lot of suspended dirt in the water so i purchased a bottle of INTERPET CLEAR POND, i added the required dose (half direct to the pond and half through the filter) it immediatly coloured all the pond water red !! i added it at 2:30 pm yesterday, went out this morning at 7:00 am and the pond water crystal clear and all the red dye has dissapated, absolutely amazed at how well and fast this stuff has worked, so if anybody else has a problem with suspended dirt i would recomend interpet clear pond. i have now ordered some sludge removing bacteria, will see how well this works !