We have a mash tun with a false bottom. We normally mash with a water to grain ration of 2.5 to 1. When mashing is complete we drain the liquid to the boiler. Then we sparge with half the recommended sparge volume and drain to the boiler. We repeat this once more. With a couple of brews now the end of sparge gravity (after the second sparge) is about 1.024 It seems we cannot get al the sugars "rinsed" off the grain. Anything we should do different. Ideally we do not want to end with more water in the boiler.