I thought hard water was good for pale ales and IPA's ... the brewer gave me gypsum to try and that solved the problem.
Yes and no. Hard water (i.e., water with hardness from calcium and to a lesser extent, magnesium) will definitely help the flavor of your beer. To accentuate the hop profile, a moderate amount of sulfate is OK as well, although excessive amounts should be avoided as the bitterness becomes "harsher" as the sulfate increases.
Alkalinity is something you have to watch out for. I have hard water that also happens to be very high in bicarbonates. I simply cannot put enough gypsum or calcium chloride in my water to reduce my alkalinity to the point that it does not throw my mash pH out of whack.
A fairly knowledgeable chemist on the brew science board helped me diagnose some of the issues I have had with using 100% house water in my beers. My dark beers had been "OK". My lighter (color and body) beers had been downright rough.
I've been experimenting with various levels of dilution (my water plus distilled) as well as the use of different brewing salts and the addition of small amounts of acidulated malt to bring my high alkalinity under control.
So far the results have been promising.
I have learned that mineral additions and water chemistry adjustments are definitely not a "one size fits all" venture. If you're going to be putting something into your brewing water, my suggestion is that:
1. You know what you water is like before any changes (i.e., get a water report)
2. You know why you're making a particular change (i.e., what do you expect to accomplish)
3. You know whether the adjustments you're making are appropriate for the beer you're making (i.e., will you inadvertently accentuate a mineral profile that you really don't want for that type of beer).
Read, read, and read some more. There are a number of fascinating threads on the Brew Science board (as well as some very smart and helpful brewer/scientists)
There are also a few helpful, relatively straightforward tools available that will help you get in the ballpark.