Pond Boss Forums INTRO Questions & Observations Water Temperature

With all things constant if my water temperature is 70 degrees on top what is the temperature drop for each foot down. I was told that it changes only by a mere 2 degrees for every six foot. I plan on getting a reading this weekend but was curious what the pro's have to say. It feels much colder than that on the 7 1/2 bottom. Also is the change much less during the heat of summer?

JDM

Temperature change with increased depth will be quite variable depending on the pond and conditions. The warmer mixed zone on top (epilimnion) is relatively uniform temp often 2 deg difference in the entire layer. I've seen a 2 degree difference in the upper 30 ft of epilimnion. It also could be as you say (2 deg/6ft) or temp can easily drop 10 degF or more in one foot (thermocline); it depends on conditions. I'm currently mixing my pond with a bottom diffuser and temp varation between top and 16ft deep is 0.3 to 0.5 deg F.

Once you hit the thermocline in a pond the temerature usually drops 2 to 10 deg F within a foot or two.

Thanks Bill for the info. I am running well water in the deepest end with a weighted tube to keep it on the bottom for 12 hours at night. I also am running my Kasco Top water aerator 12 hours only at night and pulling warm water out of the shallow end for irrigation. Do you think for my Trout pond i'm on track? Want to keep the Thermocline below 70 degrees thru the summer. As usual thanks for the info. Oh by the way i figured out what it cost to do all of this electricity wise. 2hp 230 amp Aerator-12 hours at 30 days is $34.56 month. Sub well is 3/4 horse 230 amp-12 hours/30 days is 25.92, and the irrigation jet pump 3/4 horse 110 amp-12 hours day/month is $17.28. Not bad $77.76 a month for four months during the heat of the year. Our rates at .06 cents per KW. Thought someone would be intrested in the costs.

Take Care-Jeff

Take Care

Jeff, I don't know how much water you are running from the well but well water contains no oxygen. You might be creating a problem instead of solving one. Bill Cody went thru an extensive explanation as the result of my question on this subject but I can't find his post.

Dave

jdmcalf. Doing what you are currently doing may also kill your fish. As Dave says well water can sometimes have very little dissolved oxygen in it. You should first check the dissolved oxygen (DO) levels of the well water before releasing it into the deep water zone. If you have no test kit for measuring the DO you could do a simple survival test with a fish. Run nonsplashed well water in to a large tub with the majority of the water injected below the surface similar to what you are now doing in the pond. You should try to closely match the pumping and injection method you are now using. Put a fish in the tub and see if it survives a minimum of 24hrs. Make sure the fish is acclimated to the well water temp before adding the fish so you can be fairly sure that it was not a temperature shock that harmed the fish.

Dave and Bill-good point! I was advised to do this by my Consultant who has been raising trout for 40 years so i just took his advice. I realize that well water has no oxygen but my Kasco Splasher is also right on top of the well water and it should pull the water up as he said. I wouldn't run any water in the pond if it were not neccessary to cool down the pond. The Scam Trout stress bad at 78 degrees. Bill my consultant tested my water for DO and it was as he described excellent. I will try to acclimate a trout to test your reccomendation and see if he survives. I doubt with pure well water he would last much more than a few hours. I tested the thermocline and it was at 5 feet and was 12 degrees cooler than the top which was at 70 degrees so that is good. Thanks fellas for the comments i really never thought about the placement of the well water. I hate running it in on the shallow side as that is where the kids swim and i get yelled at! haha.

Take Care-Jeff

I'm not concerned about the DO in your upper pond water that the consultant checked; it is the deep water and well water that he should have tested for DO. I doubt that the Kasco splasher can pull water from much deeper than the bottom of the intake. The cold water is quite heavy and resists being lifted compared to the warmer water adjacent to the Kasco. Thus the water it sucks will be primarily from lateral and sub-lateral zones. Be watchful of this and the DO several feet 3-4 below the Kasco should be monitored if you value your trout.

Maybe some one has tested how deep a Kasco can pull water below the intake. Depth draw may also be dependant on the hp of the splasher. All similar fountains I have tested only suck water from about one ft below the intake.

Bill-Will do! Someone that i have wrote in the forum told me my 2 hp-230 volt will pull 5 feet down. Can't remember who however.

Take Care

Jeff

Hi, I also feed well water into my pond about 4 hours per day in a 1 to 6 cycle but shoot it through six nozzles about 20 ft into the air. It has worked for me for 2 years and have had no fish kills. It also keeps a fairly large ice free zone during our cold snaps in winter.

jdmcalf - Then with 7.5' depth you should be okay. I would like to test the results of a 2 hp Kasco.