Since installing my pond, I have struggled with a way to vacuum out the bottom without dropping $200 or $300 for a pond vacuum. First I used a vacuum attachment for pools, that you attach directly to the pump. I found it tended to clog quickly and the head was too big to get in nooks and crannies. So then I attached a crevice tool directly to my canister filter. That quickly clogged too. So my husband fashioned a vacuum prefilter out of a bucket, some screen and pvc. He put cement in the bottom.