water from sink backs up into wash tubs

Hello, I am trying to troubleshoot this problem with my wash tub in the basement. The water drains real slow out of the wash tub and now when i use the kitchen sink upstairs it appears that the water is backing up into the wash tub. I have used a couple of ZEP products liquid and crystals, but nothing appears to be working. Any help would be great.

Thank you...

It sounds like you have an obstruction between the wash tubs and the outlet to your sewer line. Are the wash tubs in the basement and the sink you mentioned on the first floor, or are they both on the same floor? The chemicals usually won't fix things. If you do call a plumber, mention to him what you used. In my unprofessional opinion, you probably need to have the line snaked out to clear it. The washing machine pumps maybe 40 gallons of water in a few minutes; probably faster than draining a full tub. That is the first place you'll notice an obstruction usually.

If you have a septic system instead of city sewer lines, you may have other problems, but it could still be an obstruction.