can you have seltzer water and sugar free jello on atkins

yes on both counts

Someone correct me if I'm wrong, but SF jello is not allowed on induction. You are supposed to avoid aspartame--it causes stalls for some people. That being said, many people do have foods/drinks with aspartame and don't have any problems. If you find that aspartame slows your loss, there is a recipe in the kitchen section for jello you can make yourself using unsweetened kool-aid, gelatin, and splenda.

Someone else was asking about jello too so I hunted down the recipe--

Skamito's/Angela's recipe:

2 packets Knox unflavored gelatin
1 packet Kool-Aid flavoring (unsweetened)
8-10 packets (16-20 teaspoons granulated) Splenda to taste
One cup hot water
One cup cold water

Follow the basic gelatin recipe on the box. You can use a variety of flavors because of the amount of Kool-Aid flavors.

I'm sure you could substitute seltzer water for regular water.