Originally posted by Michael Ebaugh:
I'm trying to getting a reading / gauge on what other Pondbosses have expereinced as a normal development of a thermocline. Your input was helpful.
With only 17 gpm, I recently had a 2" steel pipe artesian well put in (3 weeks ago) and sadly the output is only a mere 3-4 gpm (less than half of a garden hose 
. with the old artesian (17gpm + the new one (felt like a waste of $$$) that adds up to only 20gpm . All these drillers were hesitant to drill the 8" hole and do the 5" pvc pipe because there is an artesian well on an adjacent property that was kicking 50 gpm (a well less than 600 ft. away). It was throttled back, as it is only for a building / small business and not needed. So, them being overly conservative, they only agreed to the old fashioned impact 2" well (mymistake!).
I am going to experiment with a cheap test well pump that runs at 10 GPM and insert a suction pipe down about 10-15 ft. and see if the flow will be able to keep up with doubling the output to 10 gpm or 600gph. My ultimate solution ($350 though) is to install a 35-40 gpm shallow well pump and have it kick in based on a timer - ON during the daytime during June, July, August.
As a protective measure, I will also be installing a 220v capable Johnson Controls A419 temperature controller on my aeration system. It will kick in when the air temp drops below about 58 degrees (fully programmable with a differential range of a whole 30 degrees!)and shut off when air temp is above 58 degrees.
I searched for months looking for this kind of device. It is nornally used in refrigeration and green houses. At only $55 it will automate cooling the pond either at night or whenver the temp drops less than 58 (or whatever I set it to.
Question - is 58 a good set point? As a fellow trout pond boss, what temp range are you able to keep your pond in the summer??? How much risk is ther of going above the dreaded 70 degrees??? I lost 200 trout three years ago (little knowledge base)when I left the aerator on full time into June (I know better now). Your pespective is appreciated Well the problem is we are comparing apples to oranges here. That is, my pond is only 1/10th acre so the cooler water entering has less volume to cool or keep cool. Addtionally I have more flow -- at least 38 gpms. My rule of thumb has been to shut off the diffuser aeraton when air temps reach 80 F. during the day, but I have took it a step farther in my previous trout pond and only ran the diffusion aeration at night in summer, as there was an algae bloom during the day that produced oxygen.
In all fairness my present trout pond is not the same one I had in the past. This one is slightly shallower and narrower but it still has steep sides and it still is about 1/10th acre. It's more retangular shaped then the other more round one. It's about 90 feet long with the deep end of 8 feet about 40 feet wide and the inflow end only 25 feet wide where is is only about 4 feet deep. The bottom slopes to the deep end to to facilitate draining and I will be spanning a shade cloth over the shallower end to reduce further warming.
58 for a cut off sounds a bit low to me but I could be wrong. I would up it to the air temps of the upper 60's or lower 70's. You can always change it if you deem it necessary. In my previous pond even when air temps went up to the 90's in summer my pond never went above the mid 60's on the surface. I did reach the upper 60's on really hot days around the shallow edge but that dropped again after the sun started to drop in the afternoon. I think I lucked out as it turnd out to have perfect temps for trout growth.
