As mentioned above, you would be surprised at how little water/space they can raise a tad in. As far as if the parents will find the tads you moved...there have been some reports of success after doing so. I however, have had to move a couple tads before and the they were completely ignored. Just keep doing what your doing as they obviously like it and hope for tue best. No matter how it turns out for those two tads, I think you made a good decision by giving them more deposition sites.