EasyTouch control and now wishing to add a 2nd pump with one drain/skimmer line

First time poster so please have patience with my mistakes.
I'm working on an existing pool/spa combo, about 2 yrs old. NOT a spillover set-up, pool and spa about 30 feet apart. EasyTouch 8SC-IC40 control and one variable speed pump. There is a desire now to be able to be using the spa and also be able to look across patio and see the shear waterfalls flowing in the pool (currently impossible with a single pump in spa mode). Access to add another pool suction drain/skimmer extremely difficult but could tap into existing pool drain line, add an actuator and feed waterfall with a new second pump (only while 1st pump is in spa mode). Ok so far, BUT really would like to make certain the second pump shuts off and new suction actuator switches back anytime the original pump is switched back into pool mode (prevent dry running original pump). I have talked with my Pentair svc. mgr. (who is great) but so far I'm told it just can't be done with Easy Touch. It could be done with IntellaTouch but not EasyTouch. EasyTouch can operate this set-up but with only one pool drain/skimmer line the second pump must always be turned off and suction actuator switched before going from spa mode back to pool mode and sooner or later someone will forget and dry run the original pump. Can anyone think of any straightforward automation equipment change that would allow this? Other ideas (relays)? Any ideas welcome.
 
Welcome to TFP!

This suggestion isn't ideal, but couldn't you feed the old pump and waterfall pump from the same suction line without a three way valve. Instead install two check valves, one for each pump, so neither pump can pull water through the other pump backwards. If both pumps are running at once they won't be "happy" with the shared suction line, but they shouldn't overheat and damage themselves either.

Another approach would be to add a current sensing relay, that detects the existing pool pump being on and turns off the new waterfall pump, or alternatively detects the new spa pump being on and turns on the new waterfall pump. This would be in addition to the EasyTouch automation's control off each pump.
 
Thread Status
Hello , This thread has been inactive for over 60 days. New postings here are unlikely to be seen or responded to by other members. For better visibility, consider Starting A New Thread.