Pond Pump

Now that we have the regeneration zone, skimmer and waterfall set and plumbed, it's time install the pump. I chose a Sequence Primer 7800PRM24 high efficiency pump. The goal for natural water filtering is to turn the entire pond volume over four times each 24 hours.  If you know (or calculate) your pond volume, multiply that number by four and then divide by 24, you will have the gallons per hour ("gph") you need to pump. Pumps are rated by gph at their maximum flow, but "head" must be taken into account to determine what pump you need. The more pipe, bends, valves and elevation the water needs to pushed through, the lower the pump's actual gph capacity will be. So even though our pond requires about 3700 gph to be moved, a much larger 7800 gph pump was called for.



First item of business was to pour a pad on which to set the pump. We used 2x4s to build a form directly behind the waterfalls, and mixed concrete in a wheelbarrow -- piece-o-cake! In a rare moment of forethought, I had previously labeled the tangle of pipes that need to be connected to the pump before they were buried in gravel (see photo below). Although the flexible PVC pipe is easy to layout (especially if you let it warm in the sun first), it is difficult to join it to PVC (Schedule 40) fittings. I found that using purple primer, as you normally would, prevented the PVC glue from reacting with the flexible pipe -- fittings could be pulled apart from the flexible pipe even after being allowed to cure for hours. After experimenting with different types of PVC glue, the best joints were achieved with regular medium duty PVC glue and no primer.

Before making the connections to the pump, I built a frame for the pump house (and I should have sheathed it with plywood -- would have saved some time cutting around all those pipes later on). Using several Schedule 40 3" x 2" T-fittings, I made a couple of manifolds to accept four 2" pipes on the suction side (3 from the regeneration zone and one from the skimmer) and two 2" pipes on the discharge side (for the waterfall and "stirring" line in the deep zone).  I put a ball valve on the skimmer line for when I want to take that off-line, like when the pond surfaces freezes over. Likewise, I put a valve on the discharge line to the deep zone in case I want to throttle that down and thereby increase the flow to the waterfalls.  More on stuff I should have done in "It's only water ..."