PS - You can do the smell test with any filter material to make sure it is
efficient. If it practically knocks you over with 'ew du pond'
you've got dead spots and that's not good.
If it smells like fresh river water (mine own description from a childhood
spend sitting in Deer Crick) then it's working.
We've used black vinyl window screening (bought in 24 foot rolls at Lowe's) and
had it come out of the filter after a year, covered in loverly muck and no dead
spots.


kathy :-)
algae primer
http://hometown.aol.com/ka30p/myhomepage/garden.html