It's always best to light acclimate, but with two T5HO's, your not blasting them like you would be with full power LED
's. I've found that with shrooms
& ricordeas, it works best to initially tuck them slightly under a rock ledge/overhang just
out of direct light, and then slowly bring them out.
The white, stringy stuff is part of their internals.... They can exude them out of their bodies to catch food or discharge waste.