I have a 1.5 acre pond (just finished the Dam), with a maximum depth of 19 feet. I will be adding closed loop Geothermal to it. I would like to stock it with SMB, YP, and RES. I will also be using it for swimming. I have been reading here about the benifits of aeration for the fish and cleanliness, and I think this is the way I want to go. Would the diffuser system be best for my application or a floating fountain? It looks like the diffuser systems are cheaper to operate. I am also curious how each type would effect the efficiency of the Geothermal loop transfer. Should I not aerate because of the Geothermal loop?

Chuck

I would go with the diffuser. I have both in my pond and just turn the fountain on for looks but, I run the diffuser 24-7. I'm sure most of the members that will respond to your post will agree. Useing a diffuser will provide oxegen to several layers of the pond from the bottom up and the fountain will provide oxegen mainly on the surface.I have no idea about the geothermal loop but, I know that aeration has worked well for my pond .

kristoffer hit it on the head wrt a diffuser providing better, top to bottom aeration than a fountain.

Since the diffuser helps mix all the water in the pond, it elevates the bottom water temps somewhat in the Summer and lowers them slightly in the Winter. I think this would make a closed loop geothermal system using the pond for the heat sink/source slightly less efficient.

You have raised this question in my mind: Since the heak sink usage in the Summer will raise bottom water temperature in the pond (I'm assuming the transfer coils will usually or always be on the bottom), will this cause the water to be warm enough to rise and serve and a means to circulate (and hence aerate) the water in the pond all by itself? I am certainly not suggesting you should go without an aeration system, just wondering how much circulation the temperature increase from the closed loop might provide in the Summer. The effects of any geothermal induced water circulation might mean that the efficiency loss from aeration will happen even without a diffuser operating.

Any ME's with geothermal experience out there who want to work a heat transfer and thermodynamics problem for this poor, ignorant EE?

In theory O2 transfer is effective via vertical circulation, but back up is always good. Owning an O2 meter is always good policy.

CWJ, I'm also in East Central Indiana. I am in the process at this moment of putting closed-loop geothermal in our pond. If you would like to see when done, you're welcome to contact me as such. Within the next week or so (weather permitting) the contractors will be here placing the loops and installing the system in my basement. Like you, I also had lots of concern around the fish etc. and I did a lot of research and checking and my concerns were pretty much unwarranted; everyone that i found with loops experienced no problems whatsoever (testimonials are always good especially from those that had the loops in their ponds for awhile). Our pond is right at an acre+ and we use a 20' windmill for aeration to the bottom up. Works great. Back of subject of the loops, i had more concern around punctures and my contractor in all his time the worse he'd heard of was a boat anchor catching on one but no punctures with hooks, not to say it couldn't/wouldn't be possible. My rule will be 'NO FISHING' in the area of my loops.

My loop is covered with a plastic net material. If you get a hook anywhere near it it grabs the hook and won't let go. That's why we don't fish near it. I don't think you could puncture the pipe with a fish hook if you tried.

From what I've heard, none have ever been punctured by a hook but then I wouldn't want to find out so that section of pond will be off limits as a precautionary measure. I cannot wait to get this geo in, my LP bills are out-of-sight $2.42 a unit and last one was $613.40 for a half fill. It's only going to get worse year-after-year. I figure this one will pay for itself in 5 years.

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.

Thanks Ted, great information. Indiana does Pond Clinic here too (matter of fact last year was at my new pond, of course, I wasn't looking at geo at the time). I have not seen a clinic with geo brought up near by, but not to say they haven't had one and maybe I just missed it....sure would have like to have attended one for the subject.