# Hydor Theo 400w Heater problems & Recommendations



## love-my-fish (Nov 26, 2009)

hello everyone, Have a Hydor theo 400w heater inherited from someone... Been using it for awhile. The other day i purchased a digital thermometer for my tank and it read 86.7 degrees Fahrenheit... YIKES!!!! Anyways so i went and turned down my heater 5 times throughout the day and the tank has still only dropped to 80 degrees..... The heater is still engaging even though its' set at 72 degrees, and only cuts out every so often...
Thoughts???? It's probably going dead right?
If so, can someone recommend a good one to buy for a 75 gallon tank.. Want one that can handle a bit more, Asking on here for personal experience...
thank-you everyone
sheldon


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## gnomemagi (Jun 13, 2009)

Chances are the heater went dead because that is overy large for that size tank.

Manufactureres under-rate their heaters so they don't get caught in a bad spot with it not heating a tank enough, but the constant on/off action of a 400W heater in a small tank will make it go bad quicker.

Chances are a 200w heater is all you need to heat a 75G to 78-82 degrees.


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## Dj823cichild (Mar 30, 2009)

I have 2 theos in my 60 gallon tank one on either side and I seemed to have the same problem. My temperature seemed to skyrocket and I turned them down and they seemed to gradually get to the point where I wanted them. Just keep a close eye on your temps, I also purchased a regular stick on thermometer and I have that in my tank as well. Just monitor your temps and you should be fine. :thumb:


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## prov356 (Sep 20, 2006)

I've got some hydor theo's that work great, and some that behaved just as your have. And they're brand new. Also 400 watt heaters, and ended up being overkill for the systems they were in. I'm wondering if that's the common issue. 400w for a 75 is way too much. I'd also agree with the 200w suggestion for your tank. I'm going to try lesser wattage in mine and see if that helps. All the properly sized hydor theo's that I have work incredibly well.

You'll find with heaters that there are good and bad in every brand. Check the reviews and virtually every one will be both loved and hated.

For best results, you can invest in a controller to plug it into, but they get pricey. I think we're getting what we pay for with heaters. I wish someone would make a Cadillac model.


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## DrgRcr (Jun 23, 2009)

I have one of their 50w heaters in my 10g tank, and I can honestly say that it is nearing the end of it's life, by way of death by hammer. I despise this thing :x ! It never returns to the same temp after a WC and the temp indicator dial is no where close to what the actual temp is. Recently after being fairly steady at 78, my tank went to 76 for no reason. I had to fiddle with the temp dial and then it went to 82. Lowered it back down to where it was originally and right back to 78 again! It's the first and only one of that type I'll ever own.


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## noddy (Nov 20, 2006)

I use Jagr heaters and have never had a problem with them. I agree that a 200w will be plenty, maybe a 150w.


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## love-my-fish (Nov 26, 2009)

Heh there: 
gnomemagi 
Dj823cichild 
prov356 
DrgRcr 
noddy
TKS everyone for your comments and especially to those whom made comments on the wattage.. I guess i was under the assumption that a higher wattage heater would be better in that it would get to the required temperature quicker and would not have to work as hard... You know, the bigger the tractor the easier it is to move the dirt...... I've got positive feedback for the most part on JaGr's and from another forum in canada GTA Aquaria it seems the big recommendation there arre STEALTH heaters.... so i'll try and make a decision between those.....But i will keep reading new things until i make it to the LFS...
again much appreciated everyone so far and to others i don't thank.
sheldon


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## Toby_H (Apr 15, 2005)

I use 2W per gallon to heat my tanks... This works very well for me... I currently have a 100W heater in my 75 gal and it works just fine...

Using more heater than necessary is asking for trouble...


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## KaiserSousay (Nov 2, 2008)

> You know, the bigger the tractor the easier it is to move the dirt....


I like the analogy, so
That big tractor would work fine on a 20 acre field, but not so good in an 1/8 acre backyard, eh?
Even J Deere makes yard sized tillers, as well as the big boys.
I agree, 100-150 watt range, would do you fine.


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## love-my-fish (Nov 26, 2009)

KaiserSousay said:


> > You know, the bigger the tractor the easier it is to move the dirt....
> 
> 
> I like the analogy, so
> ...


Tks for the comments KaiserSousay and Toby_h..Ended up getting a 150 Jager and it's working out quite well..... love how you through in the " EH " there kaiser... 

Take care folks....

Thank-you to everyone in helping me make my decision......
cheers!!!!! 
sheldon


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## kousalya (Dec 4, 2010)

Thanks for all the feedback - if I try one I will feedback the results :roll:


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## kousalya (Dec 4, 2010)

Great stuff... Im sure they will be really appreciated

Gas Ducted Heating Repairs


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## PfunMo (Jul 30, 2009)

Maybe a little looking at what happens in a heater would help understand why they go bad. We think of heaters as measuring the water temperature and then heating until the water reaches the set point. There is one really big point left out in that thinking when it is the standard heater most of us use. The heater use a bimetal spring inside the glass tube to measure the temperature. That means it does NOT measure the water temperature to shut off. It measures the AIR temperature inside the glass. That air is then heated and it transfers through the glass to the water. No big deal, huh? Not unless you want it to last a long time. If you plug a heater in when it isn't in the water, you find it heats hot enough to start a fire. What you get is a very little spring gizmo that gets heated very hot and cooled many, many times each time the water is cool. If the water is cool by 5 degrees the heater may cycle twenty times before the water reaches normal set temperature. Guess what happens to a little metal spring when it gets heated very hot and cooled often. It gets distorted and doesn't work right!!! Throw in a tiny set of contacts passing 110V opening and closing that often and you have certain failure builtin. But builtin cheaply!! For reliable operation the contacts have to be outside the tube away from the heat. It will cost you $30-35 but kill fewer fish. 
Your choice, pay $35 upfront once or pay $15 many times over and over


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## love-my-fish (Nov 26, 2009)

Hi PfunMo,,,,, I like the educational part,,, very informative. So what would you recommend in your opinion... i don't mind spending extra at all for something that will continue to work accurately.....
thanks
sheldon



 PfunMo said:


> Maybe a little looking at what happens in a heater would help understand why they go bad. We think of heaters as measuring the water temperature and then heating until the water reaches the set point. There is one really big point left out in that thinking when it is the standard heater most of us use. The heater use a bimetal spring inside the glass tube to measure the temperature. That means it does NOT measure the water temperature to shut off. It measures the AIR temperature inside the glass. That air is then heated and it transfers through the glass to the water. No big deal, huh? Not unless you want it to last a long time. If you plug a heater in when it isn't in the water, you find it heats hot enough to start a fire. What you get is a very little spring gizmo that gets heated very hot and cooled many, many times each time the water is cool. If the water is cool by 5 degrees the heater may cycle twenty times before the water reaches normal set temperature. Guess what happens to a little metal spring when it gets heated very hot and cooled often. It gets distorted and doesn't work right!!! Throw in a tiny set of contacts passing 110V opening and closing that often and you have certain failure builtin. But builtin cheaply!! For reliable operation the contacts have to be outside the tube away from the heat. It will cost you $30-35 but kill fewer fish.
> Your choice, pay $35 upfront once or pay $15 many times over and over


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## PfunMo (Jul 30, 2009)

For heaters I'm switching over to a heater that I admit is not well known and has little history. I have taken it apart and looked at the electronics and find they look pretty good. Dealing with circuit boards I found that ones that look good show that the plan is to make them good. Via- Aqua brand has heaters that have a separate sealed electronic sensor for temperature, a fully sealed and submersible heating unit and a separate control box located outside the tank. Looking inside the control box I found a nice looking circuit board with really components (diodes, transistors,relays,etc.) There is no bi-metal spring to get warped and balky. What they have described above is a symptom of warped springs. They get warped from heat and then you can't get them set precisely. The heater I'm recommending has a nice solid sounding relay mounted on the board away from all the heating. Can't see it but it sounds and feels good when it throws. I like a nice solid thump for relays that switch 110V. A titanium metal heating tube should keep me from breaking the thing. Titanium being the best metal for heat transfer. 
Two sources I know of are Commodity Axis and Pet solutions at this site:
http://www.petsolutions.com/storefr...anium-heaters/prodViaAquaTitaniumHeaters.html

Cost $35-42 with controller and mounting included.

I did a write up a few weeks back with pictures of the setup. I'm not selling it but it just looks like it is what I wanted. I have three now.


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## love-my-fish (Nov 26, 2009)

Thanks PFun once again. Well this is how we get to find out about good products from people who have electronic know how. Most of us just say certain heaters are good because we have heard it from someone else or used them for a few years and then one day, boom, it locks or dies. Guaranteed that can happen with any type of equipment but at least if we are aware of better hardware, there might be less of a chance of those failures. I am concerned when i have a lot of fish that i value so highly. I'm running a lot of jagers and I'm finding none of them are accurate, except for the newer model 250 i just bought,,,,, have to adjust them all and use a thermometer to get to the needed temperature.....

anyways, once again thank-you for your insights.. i will try and locate these and give one a try....

sheldon


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## zimmy (Aug 13, 2010)

PfunMo said:


> Maybe a little looking at what happens in a heater would help understand why they go bad. We think of heaters as measuring the water temperature and then heating until the water reaches the set point. There is one really big point left out in that thinking when it is the standard heater most of us use. The heater use a bimetal spring inside the glass tube to measure the temperature. That means it does NOT measure the water temperature to shut off. It measures the AIR temperature inside the glass. That air is then heated and it transfers through the glass to the water. No big deal, huh? Not unless you want it to last a long time. If you plug a heater in when it isn't in the water, you find it heats hot enough to start a fire. What you get is a very little spring gizmo that gets heated very hot and cooled many, many times each time the water is cool. If the water is cool by 5 degrees the heater may cycle twenty times before the water reaches normal set temperature. Guess what happens to a little metal spring when it gets heated very hot and cooled often. It gets distorted and doesn't work right!!! Throw in a tiny set of contacts passing 110V opening and closing that often and you have certain failure builtin. But builtin cheaply!! For reliable operation the contacts have to be outside the tube away from the heat.


Great explanation of how heaters work. I think I actually get it now.


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## love-my-fish (Nov 26, 2009)

For people in Ontario, Canada, a few links of places that carry them. I'm going to pick 1 up next weekend and see how it does......

http://www.petsandponds.com/en/aquarium ... index.html

http://www.bigalsonline.ca/Fish_Tempera ... ml?tc=fish

Will add more if i find any places up in ontario....


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## PfunMo (Jul 30, 2009)

My first advise for anybody is-- don't put total trust in anything you read, especially on the internet. Next time you have a heater failure, don't just trash it. Take a few minutes and tear it down to see what happens in one when it works and when it doesn't. Unplug it first!! Some heaters you can see how they work by looking without taking it apart. See the little screw thingie that turns as you set the temperature? That screw has to go through a hole in the top seal and that hole means it may leak if it gets wet. See the little metal plate the screw thingie moves? That little metal plate is real close inside a glass tube with the heater coil. That means when the heat is on, the metal gets real hot real quick. If you can see the end of the metal plate, you may be able to see the little bitty contacts that pass the 110 voltage. Those little contacts arc just like a small arc welder. Plug it in, put it in the tank somewhere dark and run the temperature up and down a few times. You may see that little arc welder working to weld the points together.

Don't trust me, go with what your eyes tell you and you might get a better heater in the deal.

I like those pictures in the ads much better than the ones I had just showing the box. Small point is that the leads between the different parts are long enough to suit me. You don't have to put the sensor right next to the heater and the control can go somewhere handy.


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## love-my-fish (Nov 26, 2009)

Can you point me to that link.. would appreciate it......


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## love-my-fish (Nov 26, 2009)

HI again, just adding a link to another informative thread to link them together for good reading for other interested parties like myself.....

http://www.cichlid-forum.com/phpBB/view ... 41#1548841

cheers and merry xmas to all
sheldon


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## ksk_che_che (Sep 26, 2007)

The numbers on top of every heater dont mean squat when it come to what the actual water temp is. They would have to be calibrated. Supposedly the Hydors can be adjusted through that little slot just under the dial, set to stay on longer or shorter so the dial on top will come closer to matching what the actual water temp is inside your tank. I have all hydors in my tanks, 50w and two 200w. I have never tried to calibrate them because I never found any directions on doing so.


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## PfunMo (Jul 30, 2009)

love-my-fish-- Got to love that sort of thinking!! There are just so many things that make us recommend one thing over another that if I don't get some hard fact that I can see or measure, I pretty much ignore some recommendations. Maybe the guy that returned all five found out he lost his job and needed the money back! Thousands of reasons things are returned, some because the item didn't work but thousands of other reasons as well. It used to be quite common for US folks to refuse to buy "Japanese-made junk". Now that the WWII generation is fading, you don't hear that much any more. The Big Al's guy may have lost his job to Chinese labor and thinks he can wage a private comeback. Ever hear the stories about the guys who would not buy certain Fords because the engines were made in Canada? Some awful place called Windsor?? :lol: Who knows?

I don't use the dial setting for temperature much as they have never seemed to be very precise at best. Some heaters don't even try and just have a +/- sign so I just start the heater and adjust as needed. It takes me several days to get the water and decorations in and by then the temperature is pretty much where I want it.


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## love-my-fish (Nov 26, 2009)

ksk_che_che said:


> The numbers on top of every heater dont mean squat when it come to what the actual water temp is. They would have to be calibrated. Supposedly the Hydors can be adjusted through that little slot just under the dial, set to stay on longer or shorter so the dial on top will come closer to matching what the actual water temp is inside your tank. I have all hydors in my tanks, 50w and two 200w. I have never tried to calibrate them because I never found any directions on doing so.


tks ksk_che_che, Yes i have learned that those numbers don't mean anything now and i'm playing with the temps to get them to where i need them. I was worried because i was thinking that maybe they were failing as i bought them all used..... I was looking for ways to calibrate them for both hydor's and jagers... but i guess it does not matter once you find the sweet spot for both heaters.


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## love-my-fish (Nov 26, 2009)

PfunMo said:


> love-my-fish Maybe the guy that returned all five found out he lost his job and needed the money back! Thousands of reasons things are returned, some because the item didn't work but thousands of other reasons as well.
> I don't use the dial setting for temperature much as they have never seemed to be very precise at best. .


Thanks my friend, yes,, i agree the temperature indicators are a waste of time,,, i'm slowly adjusting all my heaters as required until i get to the correct temperature and as i said above to the other person,,, i was just worried maybe they were failing because they were second hand heaters.

I've got someone up in canada now pricing out those heaters for me, once i get that i will purchase one or two and see how i feel about them personally... 
thank-you and i will keep you posted down the road on how i find the heaters....
sheldon


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## PfunMo (Jul 30, 2009)

I came across some of the pictures of the board on the heater I now favor. Looking at it Even the untrained person can ask how much more good electronics he can see vs what they can tuck inside a small glass tube. 








The black square item is the relay with the contacts inside and the yellow item is a transformer.
The small square black part under the blue wire is a small chip. The black and silver "cans" are capacitors that can be used to reduce the arcing as the points open and close. At the top of the picture between the green, white and brown wires is the rheostat that is used to set the temperature. Things like this are good but they just can't go inside a small heater tube.

I feel like it should work better, much longer but only time will tell.


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## love-my-fish (Nov 26, 2009)

The person i was getting to price out these heaters for me just informed me that these heaters were actually made by cascade,, any truth to that, does anyone know?

thanks
sheldon


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## PfunMo (Jul 30, 2009)

I've not heard who actually makes these. It would not be a plus to me to find they were a Cascade project only because I'm the "victim" of a Cascade 1000 canister filter. The truth is that who makes something may change at any time without us getting any information on that. Really throws knowledgeable comparisons out the window if we art not comparing apples to apples. On that point I have just found there is a hitch in comparing some of the Via-Aqua heaters. Apparently some of the reviews in the review section are for a stainless steel heater made or sold by Via-Aqua. I have not used them and know nothing of them as I only have the titanium. The difference in stainless and titanium was really pretty big to me. I think of stainless as very strong and long lasting but not really suitable for heater tubes in our use. Too strong, too slow to heat transfer and harder to form. Titanium appeals to me as it is considered the premium metal for use in super light weight use by backpackers. They make some really nice stuff but it is usually out of the price range for me. It could be they started with stainless and found problems and then started using titanium?


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## love-my-fish (Nov 26, 2009)

PfunMo said:


> I've not heard who actually makes these. It would not be a plus to me to find they were a Cascade project only because I'm the "victim" of a Cascade 1000 canister filter. The truth is that who makes something may change at any time without us getting any information on that. Really throws knowledgeable comparisons out the window if we art not comparing apples to apples. On that point I have just found there is a hitch in comparing some of the Via-Aqua heaters. Apparently some of the reviews in the review section are for a stainless steel heater made or sold by Via-Aqua. I have not used them and know nothing of them as I only have the titanium. The difference in stainless and titanium was really pretty big to me. I think of stainless as very strong and long lasting but not really suitable for heater tubes in our use. Too strong, too slow to heat transfer and harder to form. Titanium appeals to me as it is considered the premium metal for use in super light weight use by backpackers. They make some really nice stuff but it is usually out of the price range for me. It could be they started with stainless and found problems and then started using titanium?


Hi again Pfun. so i have managed to try down the manufacturer and sent them an email. Here is their responses to my questions, website: http://www.commodityaxis.com/home.aspx
Hi Sheldon,
The manufacture is Commodity Axis Inc. and are the manufacture. Yes our rating are much more conservative than others as you know there are many variables that would dictate what size heater I would use. If you are in FL 300 watt heater may not be necessary but in WI it would be. 
If you are using the heater for saltwater you must use the titanium heater. If not the stainless will work well.

Note: The controller is not water proof, Thus moisture and failure to follow the instructions will cause damage to the controller. Most of our warranty claims do to the failure to keep the controller dry
If you have any further questions feel free to contact me again

Regards
Kevin Shiotani
Commodity Axis Inc
805-383-3566 ext 102


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## PfunMo (Jul 30, 2009)

Thanks for that info. I knew Commodity Axis sold the heaters but that was not a company that I knew of before. There are quite a number of companies that just buy up products as they see them and resell . That leaves us not really knowing much about who makes them. I dealt with electronics since the days when TV's were US made and as they gradually switched from parts made in other countries to making the whole thing in other countries. If an item has more than ten parts, there is a good chance some of the parts are from other countries. Good or bad is hard to tell. I did find the price on the heaters to be a bit better at Commodity Axis than at my source, Pet Solutions. When I bought more, I went back to Pet Solutions due to good experience with them and to be sure I was getting the titanium rather than stainless.

I can fully agree that if the controller gets wet it is not going to work long. Sometimes we are not very good at following the instructions!!


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