two problems - firstly run the water through the di vessel to the pump (put a strainer on the pump) and then run from the pump to the 2 reels. secondly if you are using more than 50m microbore on each reel then there will be too much strain on the pump, also your pump should be 6ltr/min as a minimum.
Personally I'd recommend using 2 pumps and controlling them with 2 varistreams/2ecoflows