We do a local "Pond Clinic" with the state of Ohio Extension about once a year for a two county area. Our local Electric Co-op puts on a session on geo thermal as part of the program.Geothermal in ponds has been a standard in this area for the past 15 years. The question of hooking and puncturing the loops always comes up.The response has always been that it has not happened yet. If you can stay out of that area as a precaution I would but I have little concern about puncturing the loop. Not sure exactly what type of PVC (perhaps composite) the loops are constructed out of but is a very tough product.As far as aerating ponds with bottom diffused systems with loops we have not had any negative results and have installed "many" to date.Air supply to the diffuser in the loop area can always be diverted for additional comfort level in either very warm or cold conditions if it is a concern.If it is a single diffuser system a regulator can be installed to slow the diffuser down (if concerned)As far as fountains in loop ponds they will perform the same as in non looped ponds (great for looks)and surface aeration. Fountains have there place but if destratification and suppling a high percentage of aerobic bacteria and maintaining the most economical and highest percentage of DO is the goal stay with a properly sized bottom diffused system.