The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.
PFS is a common substrate around here. I've got it in two of my tanks.
To switch from gravel to sand:
1. Wash your sand thoroughly.
2. Take your fish out of the tank. Put them in buckets or tupperware temporarily.
3. Keep the filter media wet.
4. Take out all the gravel.
5. Add your washed sand.
6. Refill the tank and let the filter run a bit.
7. Add your fish.
8. Keep a close eye on your water parameters for a few days.