what is the best drain cleaner for the bathroom sink?
A plunger will normally do the job. Fill the sink half with hot water and the pull the plug. Put the plunger over the drain pipe and pus hardactuallyly it is better to hit it with the palm of your hand. You mus block the overflow and also the drain plugs if the piping is connected to the sinks as well. If the plunger does not remove the blockage you can pour 1/2 a cup Costic soda (Sodium Hydroxide) in the drain plug and add some water, wait about 10 minutes and then use the plunger again. Be verycare full when working with costic soda. wear safety glasses as well as gloves. Do not let any costic soda deluted or un deluted come in contact with your skin or any part of your body. Do not add hot water to the costic soda it may put the system under pressure and burst some of the pipes. Do not use costic soda in a septec tank system it will kill all the buggs that work for you in the tank.
Before you resort to a snake try this first. Under the sink the waste lines form a U. This is called a p-trap. You want to disconnect this. The trap is full of water (most likely funky water). Place a small pan or something like that under it so as to catch the water instead of letting it spill all over. You unscrew the fittings to remove it. It will require a pair of channel locks to loosen them, and then you can unscrew them by hand after you've loosened them. You will most likely find hair and assorted build up in the trap itself and in the drain tube that runs from the under side of the sink into the p-trap. This will also most likely be filled with hair etc. too. Clean all the pieces as best you can. It's nasty so be prepared for it. Reconnect everything and run water to see if that has relieved the problem. Make sure you tightened the fittings back adequately. Check for water leaks. If you find any, you will need to tighten the fitting/fittings a little more. You do not crank these fittings as tight as possible, but they must be snug. It's a feel thing. You get it with experience. If it drains fine you're good if not, you'll need to remove all the drain lines and run a snake through the lines to clear debris built up further into the drain lines. I don't recommend any liquid drain cleaners. Most contain a product called lye that can cause the debris to harden.
The best thing I've used so far that actually worked was something called CCLS which is a septic tank additive consisting of concentrated enzymes. This stuff is rather expensive, about $135 for a case of 4 gallons, but since I already use this to add to my septic tank I thought I'd try it in my bathroom sink drain, since on the bottle it says good for drains, too. I've had the bathroom sink drain snaked out once but it clogged back up again in about 6 months. I figured the snake only punched a pencil-sized tunnel down through the clogged pipe, so snaking it out again did not make any sense at all. It cost $110 to get the pipe snaked, and I was not about to waste more money like that so I tried the CCLS. I poured a few ounces down the drain overnight after warning the pipe first with hot water. This was a situation where the sink would fill up with water and take a half hour to empty. After several treatments it became noticeably improved. Now I always add the CCLS to the septic by way of the sink drain, and it's been free flowing ever since, over a year.
Liquids don't work well. Use a plunger and be sure to block the overflow at the top with a rag or something to prevent the plunger from just blowing air out the over flow. Put some water in the sink and plunge
