| I don't know what happened to the horizontal pipe with elbow to a slotted vertical pipe, but I agree that this would be the preferable configuration. You want the flow through the media to be as even as possible. This means keeping the distance from the basket wall to the closest slot as consistent as possible. With a horizontal slotted pipe you will not get even distribution.
The top of the basket needs to be at least 4 inches above the water line. When you bubble wash, the media is lifted above the water line and you do not want it spilling over the top of the basket. In addition, new media tends to ride a little higher than the water level. It is probably best to have a couple of inches of space between the bottom of the basket and the bottom of the floating mass of media to help it boil when backwashing.
The first static K filter I made is in a conventional cone-bottom vortex and there is an air ring in the basket. Since then, I have made some using 55-gallon poly drums as a tank and no longer use an air ring. I wash them with a garden hose jet nozzel held above the the media and shooting downward. The water jet entrains a lot of air and boils the media pretty well. I also stick the hose down to the bottom of the media and stir it a bit to make sure there are no clumps hiding down there. Then I stick the hose down between the basket and the tank wall to stir up accumulated sediment in the bottom of the drum as the water is being dumped. It doesn't take any longer to wash with the hose than the air ring. The flat-bottom drum leaves a little debris behind, but not enough to be a concern. I sure like the price of an $8 drum compared to a fiberglass cone-bottom tank. Just wish the K-1 media was not so expensive.
In one small filter, I have a mixture of K-1 media and polyethylene resin beads. Resin beads are much less expensive. The K-1 keeps the beads from packing like they do in a bead filter. The only problem is that the slots in the outlet pipe have to be much smaller to retain the beads and I have had the small slots foul and clog several times.
-s tevehop |