
OK, kids.......let's all hold hands!
It all depends on how "light, you are" , I agree a light vacuuming is not going to disrupt your cycle completely, and if you have heavy waste producers like oscars, or gold fish, it is probably a good idea. 1/2 one week and 1/2 the other should be fine.
What you DON'T want to do is...scrub anything, or discard filter material and replace. In my opinion the bacteria doesn't live IN the poo, but ON the gravel. It is good to get the poo out, to cut the total waste build up.
It is always best to try raising the temp for ich, only use medications if it doesn't improve within a few days...but if the spots are fewer, just keep up the 83 F and 50% water changes every other day, for the FULL two weeks.