3-5 sound about right, but if you're having problems w/ 1 or 2 you should cure them instead of trying to "bypass" them - there's nothing wrong with the mechanical pump as designed
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics
