[Argus]

Your 55 > "up to 50" So, you would definitely want the 300. It is better to have a heater that is rated for a larger tank than one for a smaller tank. The higher wattage heater will run less time than the lower wattage heater. So, your energy bill will not be adversely affected by the larger heater. If the heater is too small it may not be able to keep the tank temp up.

If you have a canister filter you might want to consider an inline heater. No ugly heater in the tank. Circulates warmed water well. I'm using a 200 watt Hydor ETH on a 30g. They have a 300 watt model that is rated for 53-80g.

 

[Blackheart]

But also isn't the tank water volume after you account for all the substrate in there, driftwood and plants and such much smaller than 55 gallons?

 

[GraphicGr8s]

2 -150s.

 

[goodbytes]

2 -150s.

+1
This is a much safer alternative. And consider getting Jagers instead if you are able. I personally use a Hydor ETH 300 on my 55 with a controller for safety and if you must use one large heater I would advise you to do the same.

 

[Oso Polar]

IMHO 2 x 100W heaters (or even 2x75W, if you room temperature doesn't go too low) will be the best for 55 gallon tank. If one of the heaters gets stuck in the "on" position, it'll simply not have enough power to overheat the tank too much, so it is a safer option (though a bit more expensive).

300W heater for 55 gallon is an overkill - unless your home temperature goes down to about 40 to 50 degrees F - which I doubt.

 

[DaveK]

You on need about 2 to 3 watts per gallon of water, unless your keeping the tank in an unheated garage or something.

A 100w to 150w heater would be fine. You could add a second one if you wanted backup. Although I have found heaters to fail in both the off and on condition, so I'm not sure it's really worth it. You could also go with two 75w heaters, but all too often one gets set slightly lower and ends up doing all the work.

Note - A lot of older aquarium books and such would recommend 5w per gallon. This is far too high.

 

[BBradbury]

Tank Heating

Hello Black...

Just figure on providing 5 watts of heat for every gallon of tank volume. Go with the larger heater if poss. The larger the heater you have, the less it will have to work to maintain a given water temp.

Easy peazee.

B

 

[PlantedRich]

Old discussion with the same old disagreements. Those who sell heaters and those who have not killed very many tanks full of fish will advise large heaters. I have killed way too many fish with too large heaters so I go with the smallest size heater that will maintain the temperature I want as that makes them last much longer. I've done lots of checking WHY heaters have failed and find it is the controls in most cases. A large heater makes it cycle much more often and that arcing burns relay contacts. Once burned enough they fail and it is often sticking "on" that kills the fish.
Keep in mind that fish can survive for a long time in cool water but die quickly in hot water. A heater that is not providing enough heat in a 55 gallon may give you several days to adjust the situation. But a 300 watt that sticks on can kill the fish before you get home from work.
We all have different situations and need to look at what we have. If your room stays in the 65-75 degree range, a smaller heater is safer than what is needed if the room drops to 50 degrees at night. A 300 watt heater is a death trap waiting for many of us. I use a cheap digital temperature controller to add a layer of safety.

 

[The Big Buddha]

Old discussion with the same old disagreements. Those who sell heaters and those who have not killed very many tanks full of fish will advise large heaters. I have killed way too many fish with too large heaters so I go with the smallest size heater that will maintain the temperature I want as that makes them last much longer. I've done lots of checking WHY heaters have failed and find it is the controls in most cases. A large heater makes it cycle much more often and that arcing burns relay contacts. Once burned enough they fail and it is often sticking "on" that kills the fish.
Keep in mind that fish can survive for a long time in cool water but die quickly in hot water. A heater that is not providing enough heat in a 55 gallon may give you several days to adjust the situation. But a 300 watt that sticks on can kill the fish before you get home from work.
We all have different situations and need to look at what we have. If your room stays in the 65-75 degree range, a smaller heater is safer than what is needed if the room drops to 50 degrees at night. A 300 watt heater is a death trap waiting for many of us. I use a cheap digital temperature controller to add a layer of safety.

+1 to that

 

[essabee]

+1 to PlantedRich

A single 150W heater should be enough. If you want safety add a controller. Always choose the lowest Temperature in ideal range for your tank; for the heater and keep the controller at slightly higher.

2 heaters are meaningless - you just multiply your chances of failure.

Bigger heater = less on work time + GREATER controller work time = GREATER chances of failure.

 

[PlantedRich]

Some explanation of why I say smaller is better? Other than the hazard of cooking fish, there are electrical/mechanical things to consider.
We often talk about heaters "burning out" but I rarely find a heater that has an open heating coil from the coil burning in two. Far more often I find a coil failure will be at a point where it is attached or bends around something solid. This is what I call a mechanical failure due to the heating and cooling. When heated, the coil reaches max temperature very quickly and we can see it glow on some heaters. When it heats, it expands and contracts when cooled. This movement cause metal fatigue over time and the coil breaks. Fewer heating/cooling cycles means less fatigue making the heater coil last longer?

But a far more frequent cause, I find, is the control contacts. The contacts are often tiny little points that are forced to carry 110AC at pretty heavy loads for their size. Every time the relay opens and closes there is a tiny arc of electricity. Just like a tiny arc welder, this will burn and corrode the contacts. At some point they stop making contact or they weld together.

In either case, fewer cycles, means less wear and longer life for the heater.

 

[Blackheart]

A single 150W heater should be enough. If you want safety add a controller. Always choose the lowest Temperature in ideal range for your tank; for the heater and keep the controller at slightly higher.

2 heaters are meaningless - you just multiply your chances of failure.

That's actually currently what I'm using now. I definitely wasn't about to go out and buy two more heaters. It's not necessary.

So far, the heater is doing just fine heating the tank. My only issue is that because the heater is rated only up to a 40 gallon tank, and mine is a 55, I was told it could break due to overworking so much trying to heat the larger volume of water. But so far, I haven't had any issues and I've been using it on and off for 6 months or so.

 

[essabee]

Who ever told you that "it could break due to overworking so much trying to heat the larger volume of water" is either a fool or a fraud.

There is quite a large possibility that a glass aquarium heater might crack trying to let off its heat in a very thin envelop of water; but the possibility of breaking when it is being cooled by free convective large current becomes more remote with the volume of the water current.

Rest assured as long as water is allowed to flow freely around your heater - the length of it's heater on period holds no threat of breakage.

To PlantedRich

But a far more frequent cause, I find, is the control contacts. The contacts are often tiny little points that are forced to carry 110AC at pretty heavy loads for their size. Every time the relay opens and closes there is a tiny arc of electricity. Just like a tiny arc welder, this will burn and corrode the contacts. At some point they stop making contact or they weld together.

The wire element will fuse for several reasons - you pointed out one of the common reason and I only add the other - while heating the wire throws off electron and becomes thinner and more resistive with time, and a time comes when the at a point the heat generation fuses the metal the circuit breaks. This should like your reason take quite some time.

The weakest point, and I agree with you, is the contact point of the controller. Every disconnection produces a point contact and the current causes a high temperature arc (BTW we have 220V ac in our country - so the point arc is even more acute). This arc causes pitting and as the contact points accumulate pits, more frequent pitting occur - a time comes when due to the pits; the contact point starts eroding even while not disconnecting and there is a geometric progression towards failure.

 

[PlantedRich]

This is one of those great mysteries of life which the current generation may have missed!
When cars had ignition points rather than solid state ignition modules, it was common to have bad points. They needed to be changed every 8-10 thousand miles driven and were a major reason for mechanics in every garage. The points open and close so often that they were almost always burned to various levels. One of the first steps when the car would not run was to pop the top off the distributer and check the points. I carried a small nail file in the glove box to file the points when they stuck.
We now spend so much time on computers, cell phones, etc, that there is little time to study the more mechanical items which we use.

Now when I see a car at roadside and the driver looking at the engine, I just assume there is nothing he can do, so I offer a phone!

 

[essabee]

This is one of those great mysteries of life which the current generation may have missed!
When cars had ignition points rather than solid state ignition modules, it was common to have bad points. They needed to be changed every 8-10 thousand miles driven and were a major reason for mechanics in every garage. The points open and close so often that they were almost always burned to various levels. One of the first steps when the car would not run was to pop the top off the distributer and check the points. I carried a small nail file in the glove box to file the points when they stuck.
We now spend so much time on computers, cell phones, etc, that there is little time to study the more mechanical items which we use.

Now when I see a car at roadside and the driver looking at the engine, I just assume there is nothing he can do, so I offer a phone!

Those failures were despite protection of a condenser as big as an AA cell (which itself was also a source of failure). Those days we all needed basic mechanical, electrical, and other skills to deal with all types of gadget failures - but we survived and coaxed all those gadgets to continue working. Fun days those from buy and throw-away followed these days.

sorry for the reminiscence.

 

[GraphicGr8s]

+1 to PlantedRich

A single 150W heater should be enough. If you want safety add a controller. Always choose the lowest Temperature in ideal range for your tank; for the heater and keep the controller at slightly higher.

2 heaters are meaningless - you just multiply your chances of failure.

Bigger heater = less on work time + GREATER controller work time = GREATER chances of failure.

No. They are not. I really doubt if it were truly meaningless my aunt and uncle would have run 2 heaters in their tanks on a fish farm. In Miami.

You actually cut your chances of a total loss. Failure of two heaters at the same time in the same position is indeed a rarity. If one fails off your second can at least keep a tank at a liveable temp. If one fails on then it can't heat up the tank enough to fry the fish.
I'd gladly spend $60 on two heaters to save $100 in fish.

Bump:

This is one of those great mysteries of life which the current generation may have missed!
When cars had ignition points rather than solid state ignition modules, it was common to have bad points. They needed to be changed every 8-10 thousand miles driven and were a major reason for mechanics in every garage. The points open and close so often that they were almost always burned to various levels. One of the first steps when the car would not run was to pop the top off the distributer and check the points. I carried a small nail file in the glove box to file the points when they stuck.
We now spend so much time on computers, cell phones, etc, that there is little time to study the more mechanical items which we use.

Now when I see a car at roadside and the driver looking at the engine, I just assume there is nothing he can do, so I offer a phone!

My street car I had a dual points distributor. Twice the fun! Switched over to infrared and it got even more fun.

 

[Argus]

This is one of those great mysteries of life which the current generation may have missed!
When cars had ignition points rather than solid state ignition modules, it was common to have bad points. They needed to be changed every 8-10 thousand miles driven and were a major reason for mechanics in every garage. The points open and close so often that they were almost always burned to various levels. One of the first steps when the car would not run was to pop the top off the distributer and check the points. I carried a small nail file in the glove box to file the points when they stuck.
We now spend so much time on computers, cell phones, etc, that there is little time to study the more mechanical items which we use.

Now when I see a car at roadside and the driver looking at the engine, I just assume there is nothing he can do, so I offer a phone!

I changed and gapped points on the car I had in high school. The aquarium heaters of that time were like the one you show in the photo.

I'm surprised if they are still made that way. If so, it would have to be just the very low-end heaters. Digital heaters are available and some have separate temp sensors. Aquatop has a line of such heaters. If you are concerned about arcing points, it is time to move into the 21st century and abandon 1950's technology.

 

[GraphicGr8s]

I changed and gapped points on the car I had in high school. The aquarium heaters of that time were like the one you show in the photo.

I'm surprised if they are still made that way. If so, it would have to be just the very low-end heaters. Digital heaters are available and some have separate temp sensors. Aquatop has a line of such heaters. If you are concerned about arcing points, it is time to move into the 21st century and abandon 1950's technology.

While I love tech it too is prone to failure. Just a different way to fail. And they do in fact fail. If not we'd never have to buy another replacement heater.
And so long as you have a heater coil heating and cooling all the time it can fail.

And as for new tech the SST was pretty much 1960s technology yet until 2010 that was how we got into orbit. Now we got butkiss. There is a lot to be said for "old" tech.

From Bean Animal:

Aquarium Heater Reliability

The mechanical style thermostats suffer from several problems that are an inevitable reality of their design. The bi-metal thermostats are very small and delicate. The constant bending causes rapid metal fatigue and therefore the bi-metal strip is rather prone to breaking. The electrical arcing across the contacts also takes its toll and it is not uncommon for the contacts to weld themselves together. The truth is that mechanical aquarium thermostats fail with alarming regularly. The failure usually leaves the thermostat in the ON position causing a rapid overheating of the display tank.

The electronic style thermostats also have many problems. Put simply, the circuit design in most models leaves a lot to be desired. These simplistic circuit topologies are designed to be cheap to manufacture with a low component count (to keep costs down). They circuits have a fairly high failure rate and commonly fail in such a way that the heating element remains energized.

Aquarium Heaters - BeanAnimal's Bar and Grill

 

[PlantedRich]

I changed and gapped points on the car I had in high school. The aquarium heaters of that time were like the one you show in the photo.

I'm surprised if they are still made that way. If so, it would have to be just the very low-end heaters. Digital heaters are available and some have separate temp sensors. Aquatop has a line of such heaters. If you are concerned about arcing points, it is time to move into the 21st century and abandon 1950's technology.

That's where looking inside and doing a bit more thinking can pay good dividends.
At the top is what is inside the cheap heater that fails. At the bottom is what is inside the "new" design. Is it better? In some ways but not in others. Note the black relay that has even smaller points than the lame bi-metal relay. Notice the small chips and the other components. Two things that this type of component don't tolerate well are heat and water.

If it clicks it has a relay. If it has a relay it has contact points. If it doesn't click it is way more expensive to build and doesn't like to get hot.
So we can choose how we like our failures to come around as we have several choices. I choose to be prepared for those failures as they will come around at some point.
When you've had a few more of those "quality" digital home appliances fail, you may have a different view. Digital is not always better but it does sell really well and makes lots of money-- but not for the buyer!