Item #2 below is a side view sketch of an early Vertical Matala System
When planning the height of the finished system, keep in mind the ease of removing the pads for cleaning, and the desired waterfall height which must be several inches below the top of the water height in the filter box due to gravity limitations. A standing pad can be added outside to assist with lifting the pads out and a permanent walkway and cleaning apparatus will make maintenance much easier.

Early System media tables were built using concrete stepping stone pieces mortared into "T" formations. Later systems used poured blocks of concrete that looked like upside down, reversed "L"s. These were also mortared in with concrete side supports. This created more space and a greater dirt drop out effect. Later systems have in floor drains rather than side drains. The early Lexan dividers were replaced in a few filters with Hardy-board concrete panels which were less expensive. But, these have proven to be not suitable for long term submersion, as they soften and fracture.

Internal spacing was modified to 1" of clearance between a media table and the next divider. This keeps 1-1/2" thick pads from sliding down into the following chamber. A 6-8" high settling chamber height seems sufficient. All settling chamber bottoms are tapered toward the drains from all directions. I recommend some type of gridwork over the drains. This will keep larger debris, tools, etc from jamming the exit drain valves which pprove to be difficult to access. Consider extending each outlet pipe by a few inches before attaching valves in case you ever need to replace one. Moving parts in/on plastic valves are known to fail. It is common for PVC valve twist handles to freeze or become so tight that they crack off.

All block work should have rebar reinforcement horizontally and vertically and be placed over a pad that is sufficient to hold the weight of the water and structure. If the drains will be in the floor, a PVC pipe manifold system must be constructed beforehand and the cement poured around it. I coat all PVC that is in contact with concrete with the same concrete sealer used on the walls. While pouring, you will need a barrier block that allows the pipes to protrude, yet holds back the wet concrete at the out end.

UV-C lights are a valuable investment. They kill many bad microorganisms and algae spores. In earlier designs we placed the UV light on the incoming water line. Experience shows that it is best installed vertically at the exit end of the filter. This takes a bit more piping, but eliminates heavy dirt buildup and bulb cleaning. Positioning the UV-C tube vertically and slightly lower than it's final outlet tube, eliminates trapped air in the UV-C chamber which can cause bulb failure. The bulb should also be powered from the same circuit as the pump, so water flow is always cooling the bulb while it is on. UV-C bulbs need to be replaced every spring. The life of a UV-C bulb is about seven months. It may still light up, but it's UV output drops drastically beyond that period. The good side is that the bulbs are inexpensive on eBay and usually easy to replace if access was considered during planning.

More coming soon