Pete I see I thought I read you had put the booster in. That makes sense if you are at 35/60 and that kind of flow. Some of the well guys might chime in on running your tank at more than a 20 psi differential. Your bladder is stretching more than it was designed for but I have no idea if that can cause less life but I think it would. Changing tank size won't change your run time ratio it will only change your total cycle time. Operating the pump at the same pressure range will cause the same flow from the pump and the geo will require the same amount. Now it is taking you longer to fill the tank so the pump is running longer and it drains at the same rate when the pump shuts off so the ratio doesn't change. Your flow is much higher than mine. I get away with ~ 3 gpm right now. I don't have much pumping head besides the pressure in my tank and the 30 ft or so from the line restriction. Static water level of the well is 12" or so below the basement floor. I have never tried to measure how much it drops when the pump runs. 5.5 gpm seems excessive for a 3 ton in stage one on an open loop. That number matches more of a closed loop. I would think you could get away with 5 gpm in stage 2. I guess I don't have a feel for how conservative the manufactures are on their requirements. I have a 2004 unit and it doesn't mind LWT in the high 30s. When I first moved here and didn't have much knowledge of the system I adjusted the regulator on the sprinkler valve and did get the unit to shut down on low flow. If you want to tinker this power meter is decent but might be over your budget at $155. http://www.omega.com/pptst/HHM98P.html If you want to adjust you can check LWT and power draw of the geo to optimize. If you want to add the booster later to not have the pump operate against such a big head to increase flow you could which should change your run time ratio. Really the only way to change your ratio is add more pump flow or decrease the geo flow. How do you like the Climatemaster so far? I have thought about downgrading to a 3 ton 2 stage next year to take advantage of the tax break but on the other hand it is still working so I hate to pull it out.