Chewin’ the Choya » Organic Food

Hi!
I am a new crab owner. I have a few questions…

1. I know organic is best. However, in my area some items are hard to find organic… like grapes. Should I only feed organic and strictly not feed anything that isn’t organic or is it ok to feed some things that are not organic?

2. Where is the best place to buy Greensand? I ordered some from this site and also saw it on Amazon, but haven’t seen it anywhere local.

3. I’ve read that hermit crabs like variety in their diet and I have many things for them to eat. I have been putting a mix of dry things that I leave in the tank for a few days (ground flaxseed, dried shrimp, chia seeds, oats, coco flour, nuts) and then 2-3 fresh items that I change out daily. I have been switching up the fresh items, so they aren’t being offered the same thing over and over and get bored with it. My question is should I only offer 2-3 dry things as well or keep giving a mix of all of them? I haven’t had the crabs too long and I want to make sure they are eating, so I thought a variety would be, but I don’t want them to get bored either. How many food options do you give your crabs?

Thanks!