# 50w heater enough for 20gal?



## detroit_fan (Aug 2, 2012)

I have a 20 gallon long, and after substrate was added it actually only holds 14 gallons of water. Is a 50w heater enough for that water volume?


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## Diana (Jan 14, 2010)

If the room temperature is pretty close to what you want the tank to be you might find the 50 watt is pretty good. However, if you need to raise the temperature more than a few degrees, then a 50 watt heater will probably be on most of the time (especially at night) and may not be capable of doing the job. 

There is a lot of water in the substrate, so do not totally discount that as 'no water'. Count at least half that volume as water. 
To get more accurate about the actual volume you can siphon off the water into a measured container (perhaps several 5 gallon buckets) then put the water back in. Put the siphon on the actual floor of the tank, under the substrate. You may be surprised how much water is really in there.


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## Curt_914 (Oct 6, 2007)

If your only keeping your tank between 72-75 and not giong much more then 1-2 deg above room temp you will be fine. otherwise a 100 watt will be better.

Curt


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## detroit_fan (Aug 2, 2012)

ok thanks, maybe i'll just get a 100w. i have a 150 now, it's just big and i was trying to stay as small as possible for aesthetics. 

I actually added the substrate first, then measured how much water it took to fill it up. it took almost 14 gallons exactly. I figured it would be good to know my water volume as close as possible for any future things like dosing.


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## PlantedRich (Jul 21, 2010)

I would stick to the 50W until I found it was a problem. Heaters are way over rated on most charts I see. Keep in mind that there is also a lot of heat generated by lights, filters and powerheads. If it uses electricity, it generates a small amount of heat. Possibly not much but a powerhead runs 24-7 and keeps adding heat to the water full time. 
A heater running almost full time will last much better than a heater which cycles frequently in many cases. The contacts used to switch the AC are what often fail and stick closed. They get far more arcing if they cycle often. 
A large heater can kill fish quickly. Both ammonia and lack of O2 are worse as temps rise. 
A cool fish may get sick but that is over time and can be treated. A hot fish dies quick and there is no cure for dead!


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## GraphicGr8s (Apr 4, 2011)

Use 2 50's. If one sticks it won't overheat the tank while 2 can easily heat the tank. I use 2 heaters at 1/2 the wattage required in all my tanks that have heaters.


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## Diana (Jan 14, 2010)

That is a good way to figure out the actual volume. 

I ran a lot of tanks with cheap and marginal heaters, and my house was cooler than average. I found that I really needed 5 wpg of a good quality heater. 
For the larger tanks I did indeed run 2 heaters, each with about half the watts the tank needed. Worked really well. 
But cheap heaters are not good.


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## PlantedRich (Jul 21, 2010)

So what Diana said can be restated? She ran 50 watts in a ten gallon for a tank in a cooler than average house? That sounds right to me. My last heater failure proved to be a disaster even for 50w in a ten gallon. Between 11 PM and 8 AM it was able to kill 32 bristlenose. This was in a room with a temperature of about 75 and only an eggcrate screen over the top but there was an internal filter in the tank to add heat. The tank temperature was 94 but will no extra O2, the fish were dead and stinking! 

My only question might be if anybody has found a small heater under 50 watts that is NOT cheap? 
My theory is that cheap heaters are not good and all heaters are cheap!


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## detroit_fan (Aug 2, 2012)

thanks for the replies everyone. I normally only use jager heaters, because i have used several of them for over 10 years and never had a failure in my SW tanks. but because my SW system was so big the smallest jager i have is 150w, which is big in my new 20 long. 

i learned long ago to never trust a hobby grade heater, so i use a industrial grade ranco dual stage temp controller to control my heater. when i had thousands worth of corals and fish in my 300 gallon SW set up it was cheap insurance. i love my ranco, would never run a tank without one.


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## PlantedRich (Jul 21, 2010)

When one has only a single tank, a controller is the only logical way to go with heaters. But when you have very many tanks, it get very difficult to put up the amount of money it requires for 10-15 controllers. So we have to blunder along and continue searching for a good solution. Considering how often this subject comes up, it is still a common problem.


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## detroit_fan (Aug 2, 2012)

PlantedRich said:


> When one has only a single tank, a controller is the only logical way to go with heaters. But when you have very many tanks, it get very difficult to put up the amount of money it requires for 10-15 controllers. So we have to blunder along and continue searching for a good solution. Considering how often this subject comes up, it is still a common problem.


oh yeah, i can understand how expensive it could get running many tanks. luckily with my SW system i was able to plumb everything together, so even though i had several tanks and several hundreds of gallons running i only had to purchase 1 of each piece of equipment.


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## PlantedRich (Jul 21, 2010)

Since the tanks were in several different rooms, running common water would not have worked for me. We all get to figure it out for our own situation.


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## Diana (Jan 14, 2010)

Of the smaller heaters I have had good luck (and maybe luck is all it is) with Penn Plax.
The longest lasting heaters for me have been Tronic and Ebo Jaeger. (These date from about 10 years ago- I do not know if they have changed. Probably have.) 
I have used, but do not recommend: Visitherm, Marineland Stealth (recalled) and probably several others. Tetra, Whisper or Top Fin were not good enough. 

50 watts of heater in a 10 gallon was the minimum that would keep them warm. Some of these tanks I had to wrap in a thick towel at night. I did not have overheating problems. I know it can happen. All my heater failures were fail-off. They would not come on.


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## GraphicGr8s (Apr 4, 2011)

Diana said:


> Of the smaller heaters I have had good luck (and maybe luck is all it is) with Penn Plax.
> The longest lasting heaters for me have been Tronic and Ebo Jaeger. (These date from about 10 years ago- I do not know if they have changed. Probably have.)
> I have used, but do not recommend: Visitherm, Marineland Stealth (recalled) and probably several others. Tetra, Whisper or Top Fin were not good enough.
> 
> 50 watts of heater in a 10 gallon was the minimum that would keep them warm. Some of these tanks I had to wrap in a thick towel at night. I did not have overheating problems. I know it can happen. All my heater failures were fail-off. They would not come on.


I've had many different heaters in my 32 years of tanks. The best heaters were made by Supreme believe it or not. I've had failures on all brands though. Most were fail on. And since I had 2 heaters going nothing fried. The ones that failed off were usually the heater element. Back then you could by replacement elements. Again, since I had 2 heaters instead of just one nothing ever got cold enough to cause any long lasting damage to the fish.

Over the last 3-5 years I've bought new heaters thinking (wrongly it seems) that the technology was better. Lesson? A heating element is still a heating element and from repeated heating and subsequent cooling will fail. Contacts opening and closing will eventually stick.

All that said I will never take credit for the idea. My aunt told me that was what she and my uncle did on the fish farm. She's the one who gave me my first Supreme in 1980 and I still am using it.


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## PlantedRich (Jul 21, 2010)

If one has an oversized heater it will be more likely to fail as it will cycle more often. While it is often thought that a small heater that has to run a lot to keep the heat up will wear out quickly, it is just the opposite. 
A tank heater is much the same as your toaster only with controls added to make it turn on and off. These little electronic parts are made to fit inside the heater tube. The heating coil can be as large wire as they choose. What this gives us is a coil that can be sized right but controls that are often too small. 
Each time the controls turn on, the coil has to expand and when it turns off, the coil contracts. This may eventually lead to metal fatigue and the wire may break. This gives us the "no heat" failure. 
On an oversized heater, the controls have to cycle the heat on and off much more frequently as the air inside the tube heats much quicker. At the same time the coil is being abused, the controls have tiny little contact points which arc every time they open or close. These are what I find faulty many times. The arc is just like a mini-arc welder and the points are welded together at some point. Once the points stick together, the heater is on full time. 
If the heater is large enough, this will kill your fish. 

You can now buy heaters with "improved" controls. This often means they are using new electronics inside the heater tube and should work better. They do for a while.
But guess what is about the worst thing you can do for small electronic circuits? HEAT! Putting them in a small tube with a heater is one sure way to kill a circuit board with a bunch of miniature components.


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## Slippryrock (Mar 15, 2011)

I am going with plantedrich's statements. If money is not a real concern might want to look into fluval's new E series. they have a circuit board/processor in it that is not supposed to allow it to fail in the on position. I love mine. once a person comes home to find fish soup you tend to re-evaluate your heater sizing methods. idealy you want to get the size heater that will not be able to raise the temp to fatal levels if it sticks.


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## GraphicGr8s (Apr 4, 2011)

PlantedRich said:


> I would stick to the 50W until I found it was a problem. Heaters are way over rated on most charts I see. Keep in mind that there is also a lot of heat generated by lights, filters and powerheads. If it uses electricity, it generates a small amount of heat. Possibly not much but a powerhead runs 24-7 and keeps adding heat to the water full time.
> A heater running almost full time will last much better than a heater which cycles frequently in many cases. The contacts used to switch the AC are what often fail and stick closed. They get far more arcing if they cycle often.
> A large heater can kill fish quickly. Both ammonia and lack of O2 are worse as temps rise.
> A cool fish may get sick but that is over time and can be treated. A hot fish dies quick and* there is no cure for dead*!


I'm working on that.


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## notropis (Sep 16, 2005)

Wow, I guess I've been fortunate to not have experienced fish soup due to heater issues. While I've has several fail, my fish pass due to cold exposure:redface:

I run a 100w on my 20 gal and it works great. Of course, there can be be at least a 10 degree difference between air temp and desired water temp in the winter as our house stays cool in winter.

I struggle to keep the 10 gal at a nice warm temperature.

Good luck with what you choose!


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## PlantedRich (Jul 21, 2010)

After three total wipeouts due to stuck contacts, I now have a really low ball outlook on keeping my fish warm. If they begin to get cool enough to worry about, I can almost always add warm water in some way to keep the temperature up. When I lived in cold country and lost power for three days, I lost no fish but had to work a bit harder. We had a gas water heater and I added water. The cool temperatures work very slowly so I had time to deal with the crisis. The last time a heater stuck, it killed all the fish in a ten gallon and I had no way to see it coming. 
It was a 50 watt heater that had been running for some time on a ten gallon tank. I was selling the fish the next morning so I moved them to the ten gallon for easy bagging and went to bed. When I woke up, they were dead. No warning , no possible intervention. Just dead.


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