I'd vote for going back to 25%
If 25% gave you no problems, just stay with that. It may be that the low oxygen in the well is no problem with 25% low Oxygen plus 75% high oxygen water, but at 50%/50% it is a problem.
If cleaning the tank of poop rremoves too much water, you might try making a smaller siphoning wand... get the smaller size (3/8"?) clear rigid tube from the fish store and glue a clear vinyl tube to it. You can use this to siphon up poop without disturbing the gravel too much if the poop is on the surface. You need a light touch and may have to sift out the gravel to replace it, but if the well is running dry you really may need to save the water for more important things!