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View Full Version : A quick and dirty fish tank heater for cold nights



bsfman
02-16-2013, 05:46 PM
I LOVE it when a plan comes together! I was really worried about keeping the tilapia alive in my aquaponics system during the current cold snap here in southwest Florida, so I threw together another contraption. It's a propane powered, recirculating fish tank heater! My fish are comfy and happy. I'm nipping on a double knock of 94 proof Elijah Craig 12 year old bourbon, and sitting inside monitoring the fish tank temp with a wireless pool thermometer! Life is good and the fish are happy! :)

I've actually used this concept before, but I used a coil of copper tubing rather than the PEX tubing. I am happy to report, the PEX seems to be working fine. The water in the heater is steady at 106F, the system water is holding steady at 70F, and the ambient temp has dropped to 58F on it's way to 41F tonight. Something similar to this might come in handy for those of you who keep tilapia with only occasional cold conditions. I can run the heater 24 hours on 1/2 tank of propane with the flame set as low as I have it now.

[youtube:1j9bvka9]http://www.youtube.com/watch?v=nQByt74jVQQ[/youtube:1j9bvka9]

swamp creek farms
02-18-2013, 06:31 AM
you have any problems this morning ?

bsfman
02-18-2013, 07:29 PM
you have any problems this morning ?

None at all. The ambient temp got down to 37F but the little DIY heater kept the water warm enough. The water temp did drop down to 63F at about 7:00am, but that was still 26 degrees above ambient. i could have run the propane higher and kept it warmer, but I was trying to see how long a tank would last. That tank started out almost full (not quite) and it ran 27 hours. Costs was about 67 cents per hour to run it. Definitely not practical cost-wise for long term use, but it kept my fish alive for 2 cold nights. Low is only supposed to be 52 tonight, so the tilapia are on their own. (The tank water will stay 5 or 6 degrees warmer than ambient most of the time and the fish have lived through many 50 degree nights without issues before)

Lordshandyman
02-25-2013, 07:14 PM
Howdy all...

I also live in South Florida and need the occasional heat as well. I took a different approach. I had bought a 1000 watt aquarium heater and controller used for around $75. Worked great for about two months (would hold my 800 gallons at what ever temp it was when it was turned on) then the heater burned out. Way to costly to replace. Make a long story short, it burned out the day before our last really cold snap. What to do, couldn't even order a new one quick enough.

I ran to the big box store and bought a 1500 watt water heater element for around 10 bucks and a bottle of liquid tape and hurried home. Happened to have an old microwave cord that I haphazardly cut off someones old microwave I replaced last week. I wired that to the element and gave it about 5 coats of liquid tape. First off, I didn't have time to drill a little hole and soldier the ground wire to the base, so I used black tape first to hold it to the frame, then used the liquid tape over it. That was my first mistake... later. Second mistake was not letting the liquid tape cure long enough... had a cold snap coming that night, had to hurry.

All that being said and done, the heater worked great! It held the temp of my 800 gallon system all night long, and even the next day, the water temp climbed to 70 degrees. Yeah, the day was saved. Used this for another 3 days. All was well, cold gone. Went to heat the tank up again yesterday, and snap, threw the GFI on the outlet that it was plugged into.... OH, ALWAYS USE GFI'S WHEN DEALING WITH ELECTRICAL AND WATER! What had happen was the black tape had shrunk with the heat of the element, and pulled away from the base a little. This allowed a crack in the liquid tape and water got in. Oh Snap!

So, I redid my wiring and this time I drilled a small hole in the base to soldier the ground to it. Second, I used an epoxy instead of liquid tape. Third, I ordered a 1000 watt RV water heater element to use instead (@ $11 online), so that I can use my old Temp controller as it was only rated for 1000 watts.

All in all, I calculated that it cost me around 15 cents per hour or $3.60 per 24 hours to heat my tank. Granted, after I use my controller, it will be even less as it will kick on and off as needed and not run constantly and will only be a 1000 watt again.

I just dangle the heater in my fishtank as it has no protective cover. Wouldn't want it to melt a hole in my IBC. It's not the prettiest heater out there, but the price is right.... Perhaps next time I will add some black color to the epoxy to make it look more finished.

bsfman
02-25-2013, 08:06 PM
Ingenious! But even at 4 times the cost, I'll stick with propane! (Electricity scares me and water and electricity REALLY scares me! :shock:

Lordshandyman
02-25-2013, 08:59 PM
Ingenious! But even at 4 times the cost, I'll stick with propane! (Electricity scares me and water and electricity REALLY scares me! :shock:
That's why you always use a GFI outlet for all your AP system electronics. Even the power strip that your pumps are plugged into should be plugged into a GFI somewhere! If not, please do it now. A pump can short out at any moment and fry your fish, or even you if your hand happens to be around the water. Or, some water gets splashed on the power strip and your flip flop at the same time. :shock: The GFI's save lives!

When you told me about the propane heater last year, I considered it greatly and almost ordered a stainless steel wart chiller, but the cost was high and the cold nights were over so I waited. Then the thought of having gas and an open flame running all night scared me. Specially when the wind is blowing. Besides, my pump is electric and in the water 24/7, so why not my heater too? In the beginning, I thought electric heat would be too high, but it turns out to not be that bad at all. Oh, and if you have a electric water heater in your house, every time you take a shower, you have water and electricity dancing a dance. ;)

But, your idea is grand too.... Perhaps you could design your hot water pot with a heat shield to trap more heat and make it more efficient. Also, do you have a lid on the pot when it is heating, this would help hold the heat in greatly. Oh, and even add a towel on top of the lid to hold even more heat in. When I can veggies, the lid helps a ton... without the lid, have to have it on high all the time to boil, but add the lid and low keeps the boil going. As for a heat shield, a lot of heat flows up the side of the pot and then into the air. If you had a downward shield around the top of the pot, it would trap a lot more hot air and keep it in constant contact with the sides of the pot. Just a thought.

On a side note, the wife and I have been thinking of coming up there and showing off our new baby to ya. Or better yet, perhaps you can come and check out my system and new family member at the same time. I just got my second growbed up and running.

Lordshandyman
02-25-2013, 09:13 PM
Oh, had another thought about using gas to heat.

What about using a pressure cooker full of water on top of the propane heater. Then, use a high temp hose connected to the steam vent to direct the steam into the fishtank or sumptank. Would be a lot less chance of contamination and heat loss. The only downfall is, how long till you would need to fill the pressure cooker with water again?

Or, if you have a old pressure cooker that can be modified, then drill two holes in it (probably the lid). Have your pump pump into the pot, and an outlet pipe flow to wherever it flowed before. As the pot gets warm, cool water from the tank flows in and then flows out the outlet warmer than it came in. Leave the steam vent with a 5/10/or 15 lb weight on it for safety even though it would never get this hot unless the pump died or you ran it so long you cooked your fish and veggies. Yummy, fish soup.

davidstcldfl
02-27-2013, 07:28 PM
Lordshandyman, If I remember correctly, if your running 110 volts to the hot water element, your only using about half the watts, as the rating on it.
If you didn't take that into account, then your using even less electric then you thought... 8-)


Here's a video of what some folks are doing with hot water heating elements. Some are even using stainless steel elements...
http://www.youtube.com/watch?v=_DMiYSoffBA

bsfman
03-02-2013, 10:30 PM
Running the heater again tonight. Ambient temp was 58F - water temp 63F when I lit the burner at 6pm. Ambient temp now 53 on it's way to 47F. Water temp up to 65F. 1/3rd tank of propane when burner was lit. Burner should run all night.

Lordshandyman
03-03-2013, 01:12 PM
Lordshandyman, If I remember correctly, if your running 110 volts to the hot water element, your only using about half the watts, as the rating on it.
If you didn't take that into account, then your using even less electric then you thought... 8-)


Actually, it was a 110 volt element. I wonder if a 220 element could be used with only 110 volts?

davidstcldfl
03-03-2013, 02:53 PM
Actually, it was a 110 volt element. I wonder if a 220 element could be used with only 110 volts?
Yes sir, it'll work...but it'll use about 1/2 the rated voltage.
When I bought my house, my hot water tank only had 110V going to it. It heats fatster, since I ran 220 to it.

Lordshandyman
03-03-2013, 06:38 PM
The new heater works great. No issues with the epoxy leaking water. Fishies are enjoying the hot tub tonight.

davidstcldfl
03-03-2013, 07:45 PM
Fishies are enjoying the hot tub tonight
Glad to hear it's working well... :)
I wish I had a hot tub for me...it'll be close to freezing, here in central FL, in the morning.... :(

Jeff
03-04-2013, 10:17 AM
Here's a video of what some folks are doing with hot water heating elements. Some are even using stainless steel elements...
http://www.youtube.com/watch?v=_DMiYSoffBA

The same guy in that video built my heater for me, and it worked GREAT during the winter. When outside temps were in the high 30's, my tank was sitting above 60 degrees F.

Not trying to hijack a thread, but I filmed a video of me OPENING the heater, and then showing it installed in my system (skip to 1:11 to start right with the aquaponics stuff):

[youtube:2b19g50m]http://www.youtube.com/watch?v=Z5wKv8QSo9E[/youtube:2b19g50m]

If you want to see this unit actually being made, from start to finish, then you can watch the long video here. In this video, Bob (FiberInspector) is actually making my unit. This is good for you DIY guys!

[youtube:2b19g50m]http://www.youtube.com/watch?v=QWZ3qQ3R8_A[/youtube:2b19g50m]

The only downside: it ain't cheap on the electric bill! Depending on how cold your ambient temps are, and how hot you're heating your tank, it can hit you hard in the wallet. I saw my electric bill go up well over $100 because of it.......but then again, I was trying to heat my UNINSULATED tank to 68 degrees when it was below 40 F outside. Once I realized how expensive it was, I adjusted it down to 58-60 degrees.

The beauty of this heater is that it's hands off, and with a thermostat, it controls itself to whatever I set it to. So I don't have to worry about it getting too hot or too cold.

jackalope
03-04-2013, 10:42 AM
Lordshandyman, If I remember correctly, if your running 110 volts to the hot water element, your only using about half the watts, as the rating on it.
If you didn't take that into account, then your using even less electric then you thought... 8-)


Actually, it was a 110 volt element. I wonder if a 220 element could be used with only 110 volts?

This is just a thought, but I think what you're showing and describing here is almost the same thing as those plug-in elements for heating a cup of coffee (they sit in the coffee cup and heat up the cup of coffee) IF they still sell such an animal :lol: I don't know anything about the wattage, etc., but I believe you can get either 12 volt (for RV) or 120 Volt (for the home) at an RV supplier. They sit directly in water, and since they have a cord on them, they could be connected to a controller. Admittedly, they probably wouldn't be as effective as your unit for an 800 gallon tank, but could be used for smaller applications. This is just the kind of idea that makes this forum so great ..... an exchange of ideas for anyone who just wants to get going and doesn't have a bankbook as big as the Unabridged Webster's Dictionary :lol:
Just my 2 centavos ......

jackalope
03-04-2013, 10:58 AM
I LOVE it when a plan comes together! I was really worried about keeping the tilapia alive in my aquaponics system during the current cold snap here in southwest Florida, so I threw together another contraption. It's a propane powered, recirculating fish tank heater! My fish are comfy and happy. I'm nipping on a double knock of 94 proof Elijah Craig 12 year old bourbon, and sitting inside monitoring the fish tank temp with a wireless pool thermometer! Life is good and the fish are happy! :)

I've actually used this concept before, but I used a coil of copper tubing rather than the PEX tubing. I am happy to report, the PEX seems to be working fine. The water in the heater is steady at 106F, the system water is holding steady at 70F, and the ambient temp has dropped to 58F on it's way to 41F tonight. Something similar to this might come in handy for those of you who keep tilapia with only occasional cold conditions. I can run the heater 24 hours on 1/2 tank of propane with the flame set as low as I have it now.



Good idea! I like this, may give it a try next winter if we winter here in Tennessee again (the wife hates Montana winters :lol: ) have you had any problems with the PEX taking the heat, such as going soft on you etc.? Another question would be is how were you able to keep the PEX off the bottom of the cooker/away from the higher heat conducted thru the metal? PEX is pretty spendy in Montana, in your opinion, would vinyl tubing work just as well, or would it be less effective within the cooker itself?

bsfman
03-04-2013, 12:57 PM
Good idea! I like this, may give it a try next winter if we winter here in Tennessee again (the wife hates Montana winters :lol: ) have you had any problems with the PEX taking the heat, such as going soft on you etc.? Another question would be is how were you able to keep the PEX off the bottom of the cooker/away from the higher heat conducted thru the metal? PEX is pretty spendy in Montana, in your opinion, would vinyl tubing work just as well, or would it be less effective within the cooker itself?

The PEX does sit on the bottom, but it has not been an issue. Essentially the temp on the bottom is water temp - despite the heat being applied there. I only heat the water in the cooker pot to about 130F. Vinyl tubing would probably work as well. The cold water pumping through the tubing keeps it cooler than the hot water through most all of it's length so melting is not an issue. I have used vinyl tubing in homebrewing beer and though it gets soft and flexible, I have sucessfully used it at temps up to 175F without issues.

David - WI
03-04-2013, 05:49 PM
I would think that if you dropped the whole thing into a metal trash can with a few small holes near the bottom for air and a couple larger holes in the lid for exhaust, you could triple or quadruple your "gas mileage"?

bsfman
03-04-2013, 07:33 PM
I would think that if you dropped the whole thing into a metal trash can with a few small holes near the bottom for air and a couple larger holes in the lid for exhaust, you could triple or quadruple your "gas mileage"?

Probably so. But for the few nights a year I need to augment heat, it's not worth the effort to me to do so.

David - WI
03-04-2013, 08:16 PM
I would think that if you dropped the whole thing into a metal trash can with a few small holes near the bottom for air and a couple larger holes in the lid for exhaust, you could triple or quadruple your "gas mileage"?

Probably so. But for the few nights a year I need to augment heat, it's not worth the effort to me to do so.

Ahhh... than it's nowhere NEAR cold enough where you are! LOL

bsfman
03-05-2013, 05:35 AM
Ahhh... than it's nowhere NEAR cold enough where you are! LOL

David, for the past 8 yrs, I've journeyed up to your neck of the woods on tour with my band. I got cold up there at night in July - August! Very happy that after 10 years together, the band broke up and I don't have to go this summer! :). You can find me down here this summer chasing tarpon in my kayak!
:D

David - WI
03-05-2013, 05:43 AM
I had an older customer from Arizona who always asked why anyone would want to live up here?

I told him that nobody did, but when the ancestors came through this area on the wagon trains, it was summer so they sat around and drank beer and had a nice time... but our summers end so quickly that they got snowed in and had to eat the oxen to survive. Then they were stuck here!