If you are installing a RetroDrain and are connectimg it to a niche skimmer, substitute "settling chamber" in the above illustration for plumbing purposes. If your skimmer operates using a submersible pump in the skimmer, substitute the end of the pipe labeled "Tangential feed pipe" in the above illustration as the end of the pipe plumbed from the RetroDrain passing into the skimmer (see insructions below).
Step by Step instructions:
Use a minimum pipe size of 2”. Larger sizes will improve “drafting” of water to settling chamber or niche type skimmer.
Plumb from the drain to the skimmer, using 45 degree fittings or even 22.5 degree fittings wherever possible. Keep a close profile to the floor and walls of your pond. See Picture at bottom of this page.
You can elect to pass the drain pipe through the liner, below the pond’s surface using a bulkhead fitting. Another option is to plumb the pipe up and over the edge of the pond - as long as you proceed to the external pump location, maintaining elevation of the pipe below surface water level of the pond, outside the pond. This provides for a "flooded suction" to the pump.
Install a swing (not spring) check valve before “leaving the pond”.
Install an isolation knife valve before entering the skimmer.
You can elect to pass through the skimmer wall with a bulkhead or pass the pipe up and over the top of the skimmer, then (very important) continue pipe down to within an inch of the floor of the skimmer, near the pump’s intake area. Preferably pass this pipe into the “dirty, incoming water side” of any media that is in the skimmer.
Longer distances from the drain to the skimmer should have larger pipe to create less resistance to flow. More resistance to flow means less drafting from the drain into the skimmer box or settling chamber. We prefer to see a split of 70% volume through the drain, 30% through the skimmer weir.
If more volume is needed for the skimmer operation, adjust by slightly closing the isolation valve you installed.
If your skimmer is operated with a centrifugal pump, see illustration above. And additionally read for direct drive skimmer: Gravity Fed with Skimmer.
Tech Support Line: 707 853 0118. Ask for Bruce