I couldn't afford a dream mat or ripple mat, so I decided to make my own...total cost about $40. I bought a cheap $6 rubber mat from Bunnings and a rubber mat from ebay for $16.95, Sika Black 291 Marine and Construction sealant for $15.91. I already had a fine ripple mate which I stuck to the Bunnings mat. I cut down the circles facing the oncoming water but I don't think that was necessary as the heavy stuff was collected in the uncut circles. I tried it out today and it worked fine. I took out the cloth mat and moss from the sluice.