Hi Monica,
Grounding oneself can be "good medicine". It is okay to be utilizing medicine and practice SFQ. I would do your grounding, then start your exercises. As soon as you "merge with the universe", you begin your SFQ qigong, and your grounding merges with that shift too. Qigong is a transformative practice. Your spirit and body will become stronger, and you will come to the capability of giving or helping, and being a strong positive transformative energy. You become the medicine for the earth.
Using filters or protection, or a bubble as you say, is also more singular technique, versus being a 'practice'. Put this, if you do it, after you finish your SFQ sessions. Keep your sessions pure to themselves relative to these techniques. Your SFQ practice is transformative, and will grow outwards, transformatively. It will touch what came before or comes after. Looking at this bubble piece would be good for you. If it stems from fear or worries, you reinguage with an extra energy, post practice, that is not good for you. Walking from your practice, in the energy result of that practice, is best. You are more present, relaxed, more open in the sense of holding less energy that is not good for you, or that you don't need.
Not mixing energy practices, in general terms, pretains more to other , more extended practices like other qigong routines, tai chi, yoga, 'sets of exercises', more complete forms... These 'practices' set the energy moving in patterns relative to the practices. It is best to keep them apart, giving them their own time.
Engage as fully as you can with SFQ. It will help you with your sense of stability that pretains to grounding, as well as any sense of vulnerability, via strengthening spirit, as well coming to higher levels of understanding,...experiencing or seeing wisdom and truth in that.
love,
gallen
