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URGENT - Please Help with Electrical Inline Water Heater with Temperature Controller

Hi everyone!

I am a koi hobbyist living in Montreal, Canada. I have an 8000 gallon outdoor pond in which I have 24 koi, ranging in size from 12" to 24". I could or should I say "should" leave them outside for the winter, but I've opted to bring them inside now for many years. I used to have 3000 gallons in my basement winter set up, split between two tanks. One, which was a 1700 gallon above ground pool developed several leaks over the years, so I trashed it last summer leaving me with the one tank, a 1200 gallon capacity. Needless to say, this year fish are very stressed due to being overcrowded. I could give you plenty of more details as to how I care for them,may need for a hospital tank, but I'd rather get straight to my question. :)

Two fish have developed two small ulcers which I am currently treating, but I need to raise the water temperature from its current 60 degrees F to 76-77 degrees F.

I'm on a restricted budget (unemployed), so I am not in the position to purchase an expensive inline spa water heater or anything else in the same price range.

I've attached a couple of videos of DIY inline heaters, easy to make for under $100., but need to know what supplies I would need to change up if going with a higher watt system. I would like to use either a 1500 or possibly 2000 watt element. I'm assuming that the first video below is a 1000 watt or less, because nowhere is wattaged mentioned (unless I missed it). Second video is well under 1000 watts.

So if any of you have experience with these type of DIY devices, kindly advise the correct parts required, meaning: element, size of thermostat controller and If I need a solid state relay? The relay part has me confused as I have never used one in any electrical application. Remember, this is for a 110 outlet, which already has a 1/4 horsepower pump and a hefty air pump plugged in to. What amps should I have on this circuit? (maybe I need to call a licensed electrician to increase amps at my electrical box?)

So here are the a couple links for the general idea.
Please answer ASAP as my two sick fish need more warmth in order to heal.


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Good point, didn't think of that.

To make things simple it's best to think simplistic. And the simplest way known to heat water is in a pot on a stove, whether wood, gas or electric etc...

Now, a very simplistic stove capable of transferring around 1300-1500-2000 watts of heat to a pot of water is the well known single burner "Hot Plate". Good heavy duty stainless steel "stock pots" are certainly fish and food safe, and readily available.  In Aquaponics, it's important both that water circulates/flows throughout the system, and that temperature is pretty homogeneous throughout.

So Chris, couldn't your system be simplified by circulating your water through a stock pot on a hotplate? Food for thought. Hope it helps.

Hi Glenn, thanks for the reply.

First let me say, by NO means am I a scientist, but isn't what you are suggesting basically what I am already doing? I have a 1500 watt element plugged through the wall of one of my filters. My 1200 gallons turn over 3500 GPH due to pump size.... So your method would have to be gravity fed at a slower volume... Maybe I'm missing something within your suggestion, if I am I do apologize.

Temperature this morning with tank covered, heater running and with the addition of warmer water changes is at 24.8 Celsius, so for me that's close enough. If I had the extra money I'd just install a stronger element and a dedicated breaker, but that notion is almost moot now. In all likelihood we will be losing our house soon due to my health issues, so will have to sell off my fish... So for now just doing my best in keeping them alive.

I do appreciate everyone's help. Thanks for chiming in with great suggestions and solutions... I'm indeed very grateful and the kindness that you have all shown will never be forgotten.

Cheers always,
Some good news to report -

As you may know I was playing around with covering and uncovering the tank since adding a small space heater to the mix. Decided to recover the tank with tarp a few days back due to a small amounts of heat loss. During the past few days of being covered I have seen a slow increase in temperature. Last night before bed I noticed that water temp had finally surpassed the temperature controller's set point of 25.0 Celsius (was at 25.1) which kicked the controller into cooling mode (inline element off). I went to bed happy.

So now, less than 24 hours after that, temperature has climbed a few points more to 25.3 Celsius. Needless to say I am thrilled. Also worth mentioning is the fact the we are experiencing milder weather the past few days, so this too has helped. My gut tells me that covering and increasing room temperature along with a dose of warmer (hot) water to my water changes has more or less stabilized my situation. Now I just have to wait and see if my fish respond to treatment.

Enjoy the balance of your weekend!
Hey guys,

Guess I'm not lucky... Last night I got a "EE" error message (and alarm) in the display window on my STC 1000 temperature controller. Checked manual and learned that this error is with temperature sensor probe. I opened up project box and checked sensor connections and all was good. Powered up again and stil got the same message, so I unplugged power and allowed unit to rest for 30 minutes. Plugged back in and no alarm, but when handling the temperature probe at its end between my fingers, temp jumped around wildly, going back and forth from way minus to way plus Celsius.... Eventually EE message was back with alarm.

Amazon is unable to replace unit from this particular vendor, but is willing to offer me a full refund once shipped back to them.

So, my question is, do you think this is just a defective sensor probe or the STC controller box itself. Perhaps some of you have had same issue?

Chime in if you have any suggestions.

Unlucky in Montreal, Chris

"EE" error displays on most single loop controllers mean that the probe or sensor wiring is either open, or shorted. If you can use a volt/ohm meter, disconnect both probe wires from the controller and measure the conductivity/resistance across them. you should get about 12kohms. or 12000 ohms of resistance. higher to infinity means the wire or probe circuit is broken. much lower than 12k or zero means it is shorted, and the wire or probe is pinched or touching where they shouldn't.  temp probes sometimes are polarity sensitive and could fault the controller if reversed.  The observance of rapid change while touching the probe is most indicative of a loose or partial open, OR in some cases can indicate that a chemical such as a penetrating oil like wintergreen or spearmint is present.  The good news either way is that it is probably not a controller damage issue, but is just the probe or sensor. And those are often standard run of the mill probes that can be replaced with those readily available at electronics supply stores. Kinda like radio shack use to be but still exist as electronic component suppliers in the yellow pages. If you find a store, take your probe and wire to them and ask for advice.

hope this helps.

HI Chris,

I was wondering how things were going.  I figured no news was good.  Spoke too soon.

While you are waiting for the resolution from Amazon, I would say you could put the heater either on a timer, or just plug it in at night and unplug in the morning.  Since it is heating quite slowly, I don't imagine you run much risk in overheating the water.  

Technical ?'s aside.   How are your fish doing?  Have they healed?


Thanks Glenn and Steve for your input.

I've decide to return controller for a full refund and order another one from a different vendor on Amazon. Amazon will pay for return shipping as well as the new unit and will even expedite shipping.

I am happy to report that fish are almost totally healed and are looking better each and every day (knock on wood). Still keeping a watchful eye over the entire situation, but for the most part I feel my crisis is over. Thanks to all who helped me through this! I'll give additional updates in the weeks to come.

Amazon is refunding me for STC without having to return it... So I want to order just the probe, but most 2 meter probes that I've seen have a 3 wires (one is a ground) whereas the STC has only two wires. Is this three wire probe compatible with my STC, and do I need to attach the ground or can I just nip it off and not bother grounding.

I'm in no rush and this one is inexpensive from China. Check out link and let me know.

I think this one is a better bet (two wire)? Is stainless or plastic end better for water? I sometimes salt the water? Also, some don't indicate "waterproof"... Should I be concerned?
Hi Chris

- you need to check what type of sensor your controller requires. Some sensors are serial(digital) devices while others are analog.



How are the fish doing?  

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