The toilet in my basement gurgles when the upstairs toilet is flushed. The toilet in the basement does not flush properly (when I flush it just fills with water). If I hold the handle it will empty completely but start to gurgle when bowl is refilling. I've tried plunging and I've tried shooting it with the "Kleer Drain" but to no avail. What am I doing wrong or what else can I do?

Thanks

You're looking the wrong way. Think vent. Your toilet's venting through the water in the trap. Check and clear the vent. Good luck, Tom

Looks like you'll be climbing onto your roof if you really want to do a good job. Run enough snake down the vent to reach roof to basement floor plus another 10-15 feet.