Question:
My friend has a drinking water filter underneath her sink. I tightened (by hand) the tank (holds the actual filter) as best as I could, but water is coming out of the threads. It's not completely closed because it's too hard to screw it any further. Any tips on tightening the tank?

Answer: Shut off the water and relieve the pressure in the filter. Remove the 'tank' (housing) and check that the o-ring seal is in the correct position and there's no dirt on it or the surface it seals against. Tighten the housing hand tight and check for leaks. If it still leaks repeat. It should seal if there's nothing wrong with the o-ring etc.. Yu can't tighten against the water pressure.

You can always use a strap wrench. You can get them almost any place, Sears, Walmart, Auto Supply, etc. And they are quickly available, rather than having to wait for shipping. And probably no more expensive.