Soil Flushing weekly

I have read quite a bit on this forum and hadn't seen any info on flushing weekly in soil. I think a Hydro reservoir is supposed to be flushed weekly but I was talking to the guy at the hydro shop and he was saying I should flush my plants with 3 times the pot size with water weekly so a 3 gal pot would be flushed with 9 gals of water weekly. I told him I was growing in soil. Any help would be greatly appreciated
Thanks in advance

with soil you should flush once a month.......if you encounter serious problems like nute burn or what not you should flush immediately..... as always you should be keeping track of your PH

I don't know anything about hydro, so i can't help you there