I've tried all kinds of clog removers and after using them the tub still drains slowly after awhile. My plumber explained the cause, something about this pipe being smaller than the rest of the pipes in the house, the other drains are fine. He suggested to try boiling a pot of water with plain salt and then immediately pooring it into the drain to clear the sludge. Has anyone heard of this method before, will this harm the pipes?

The hot water should not harm your pipes. The original Draino crystals did just that when combined with water - heated the water even hotter to dislodge soap scum, grease and gunk that had built up in the pipes. You may try a plumber's snake if the hot water cure doesn't work. You'll be amazed what the snake will extract from what you may think is a clean drain.

I have found that drain cleaners don't remove the hair. So When mine starts running slow I remove the "strainer" and pull out the hair then pour the drain cleaner down the drain and let it sit there before pouring the hot water down the drain.

Instead of using drain cleaner fill the tub with a few inches of hot tap water...as hot as you can get it and dump in some laundry detergent, let it sit for about 15-20 minutes and then pull the plug and let it drain, it cleans out the drains really well and makes the washroom smell nice at the same time.

Sagus and I were giving our boys a bath, one of them pulled a roll of toilet paper into the tub and it disintegrated.. and of course they pulled the plug and quite a bit went down the drain and stopped it up. I told Sagus about the hot-water-down-the drain thing.

With a great deal of reluctance (and quite a show of suffering "humor-the-little-woman" attitude... okay NOT that bad but nearly ..lol), he heated a kettle of water and poured it down the drain...

Low and Behold..IT WORKED (he stopped doubting me).

It is worth investing in a small strainer, obtainable in a hardware store (after you measure the drain across), which will catch the hairs for disposal other than down the drain. Consider using same in sinks also.