What a load of rubbish, never heard any thing quite so stupid in my life.
We should make a list. One of my personal ones is the lfs's that tell people that their water tests are fine. I think I'll make a color card that starts with really fine, and goes on to pretty fine, fine, almost fine, could be finer, not really fine, far from fine, and nowhere near close to fine.
When I'm filling tanks with the hose, wide open gives me about 7 gpm. I have dumped full 5 gallon buckets into tanks in under two seconds. Neither has caused a problem.
Soliquid; Find another shop, keep going to this shop for advice, but don't listen to a word of it. Post it here, I got a good laugh.

I have also pointed out that fish were dead and they assure me that they were sleeping.
The have also told me that its okay to up 5-6 fancy gold fish in a five gallon tank. At another shop when I was little, they sold me 2 fancy gold fish in one of those critter keepers that many sell hermit crabs in with no filter, I had them for about 6 months until they died. Obviously I know now that, that is completely unexpectable and was basically torturing the fishes. Then there was the time I first got started ( like real stared, not the buy a fish put it in the bowl and volia your a fish keeper stuff) in this hobby and the guy at the LFS sold me a rainbow shark, a platy (sp?) and a tetra to go in the same tank. He also let me know that i could keep them in that tank for there whole lives. My shark grew to four inches in about 5 months and was five in a half inches in a little less than a year. Partly my mistake(should have researched), but his as well. The one and only place that I listen to when giving my advice is my local mom and pop shop. They really know there stuff(most of the time)
I'm looking forward to seeing this thread continue.