The two vs one heater argument again...which system works harder to maintain temp.

[Emeraldtarpon]

Hi TTFers,
ive got a 4ft, 200L (44gallon) tank that i'll be setting up in approx' 3-4 months time.
Im thinking of heating it with 2 x 150watt heaters.
Winters are cold here...house night temps drop to approx' 10 celcius (50 degrees F) so i will need to lift tank temp by 14 celcius at night to get to set temp of 24c (hence, my reason for 2 x 150 watt).
Of course, redundancy is also a prime issue that's covered when using 2 heaters, as well as a more even heat distribution throughout the tank.
One of the things ive never really understood though is the following
Would 2 x 150w heaters work less to maintain temp than one 300w heater?
I suppose there's several arguments for this but im just after a general consensus to get a better understanding.
Appreciate your time guys, cheers.

 

[Byron]

I would not go below a 200w heater, probably more a 250w or even 300w, and definitely two of them, one at each end. The higher wattage heaters tend to be longer working. I always have one next to the filter intake at one end, and the second next to the filter return at the opposite end. This does work better to heat the water and the heaters will not wear out as fast or are less likely to fail. Another option is a canister filter with a heating element. I had an Eheim Pro 2 with this on my 90g tank and the water temperature was bang on for 20 years.

 

[10 Tanks]

Hi TTFers,
ive got a 4ft, 200L (44gallon) tank that i'll be setting up in approx' 3-4 months time.
Im thinking of heating it with 2 x 150watt heaters.
Winters are cold here...house night temps drop to approx' 10 celcius (50 degrees F) so i will need to lift tank temp by 14 celcius at night to get to set temp of 24c (hence, my reason for 2 x 150 watt).
Of course, redundancy is also a prime issue that's covered when using 2 heaters, as well as a more even heat distribution throughout the tank.
One of the things ive never really understood though is the following
Would 2 x 150w heaters work less to maintain temp than one 300w heater?
I suppose there's several arguments for this but im just after a general consensus to get a better understanding.
Appreciate your time guys, cheers.

Hello. Your tank needs 5 watts of heat for every gallon of water. That's 220 watts. Two 150 watt heaters is more than enough. The 300 will work harder than the two 150 watt heaters. Just place the heaters at opposite ends of the tank and you're good.

10 Tanks (Now 11)

 

[seangee]

I have 2 in all my tanks so that if one fails there is a spare. I also use an inkbird controller to protect against failed thermostats.

 

[Slaphppy7]

50F indoors at night?

 

[TwoTankAmin]

I have been doing outdoor tanks over the summer for a number of years. I want to have the longest possible season for this. The determining factor is the overnight lows. My general rule of thumb is that once the nighttime temps are dropping below 55F (just under 13C) It becomes a losing battles and time to shut down. I am able to deal with a single night drop into the high 40s, but I have to cover the tanks with towels and blankets.

I put a minimum of 15 wpg (and 20 is even better) on these tanks. I also need to keep them on the warm side. This means I do not want the water to drop much under 77F (25C). I am working with plecos which like it warm.

Part of my problem in terms of the low temp. nights is that they tend to occur as the daytime maximums are also dropping. My fish can do fine when the temps outside are in the 90sF and the water temps are close to that. My one edge is the place where the tanks are set up is a screened terrace where 3 walls are screens. I am able to keep the tanks pretty much out of direct sunlight.

On all of my pleco tanks I use an Azoo controller. It is more basic than the Inkbird which I did not like- too many settings involved. The Azoo works in C but I work in F. So I do not need to set any ranges. The controller goes on when the temp. in C drops by 1. But that is almost 2 dg F and that creates a range of +/- 2F to make the heater go on and off. I also set the heaters a few dg F above where I set the controller.

I can change the temp. setting on the Azoo controller in about 10 seconds. After reading the directions on the one Inkbird I tried, I packed it up and sent it back.

Finally, I almost always use two heaters and two or more filters on my tanks. I do not do two heaters on tanks of 20 gal. or less. I also always want to place heaters horizontally close to the bottom. This offers a number of benefits:
1. It can make it easier to hide the heater behind decor/plants.
2. I disperses heat up over a longer length than when the heater is upright. the helps spread the heat.
3. Since heat rises from the lower portion of the heater which is arrayed lengthwise, it heats more water which rises creating circulation.


@Byron
I have 5 Eheim Pro II, three are running for many years. One is for spare parts and the other I never put into use, it is a 2028 while the others are all 2026. I use Hydor inline heaters as I want all the interior space of my filters for media.

edited to fix a mistake caused by OBS. I changed the min. wpg for my outdoor tanks to 15 and preferably 20 wpg where I originally posted 10. Apologies.

 

[Emeraldtarpon]

Hello. Your tank needs 5 watts of heat for every gallon of water. That's 220 watts. Two 150 watt heaters is more than enough. The 300 will work harder than the two 150 watt heaters. Just place the heaters at opposite ends of the tank and you're good.

10 Tanks (Now 11)

Hello 10 tanks,thank you for your reply.
Do you think id be ok with 2 x 100 watt heaters? (will probably be titanium heaters).

 

[Emeraldtarpon]

50F indoors at night?

Hehehe...the house is heated until bedtime, switched off, and then back on in the morning.

 

[Byron]

Do you think id be ok with 2 x 100 watt heaters? (will probably be titanium heaters).

No. @TwoTankAmin has recommended 15w per gallon, which would be 600w total in a 40g (200 liter) tank. I said basically the same. The other thing to keep in mind since you mention cool temperatures (50F/10C) is that aquarium heaters are intended to work when the ambient. room temperature is only 10 degrees below the intended tank water temp. This in itself will more quickly cause malfunction of heaters as they are having to do basically the impossible. A room heater would help here. I kept my fish room at 70F during the winter months, so the tank heaters only had to maintain the temp six to eight degrees above the room temp.

 

[Emeraldtarpon]

I would not go below a 200w heater, probably more a 250w or even 300w, and definitely two of them, one at each end. The higher wattage heaters tend to be longer working. I always have one next to the filter intake at one end, and the second next to the filter return at the opposite end. This does work better to heat the water and the heaters will not wear out as fast or are less likely to fail. Another option is a canister filter with a heating element. I had an Eheim Pro 2 with this on my 90g tank and the water temperature was bang on for 20 years.

Hi Byron,thank you for your reply.
Im thinking of getting 2 x titanium heaters (placing one either end of course).
I have an Aqua One Ocellaris 1400 uv canister filter which should create a decent, moderate flow in the 4ft so the heaters will be able to disperse heat more evenly and efficiently throughout the tank.

 

[Byron]

Hi Byron,thank you for your reply.
Im thinking of getting 2 x titanium heaters (placing one either end of course).
I have an Aqua One Ocellaris 1400 uv canister filter which should create a decent, moderate flow in the 4ft so the heaters will be able to disperse heat more evenly and efficiently throughout the tank.

This is fine, but the two need to be substantial heaters. I would not go under 250w, and probably 300w heaters, two of them. And the ambient air temperaturein the room is still an issue, whatever kind of heater. The inline heaters might be better in this situation, I don't know as it has never been a problem for me.

 

[Emeraldtarpon]

No. @TwoTankAmin has recommended 15w per gallon, which would be 600w total in a 40g (200 liter) tank. I said basically the same. The other thing to keep in mind since you mention cool temperatures (50F/10C) is that aquarium heaters are intended to work when the ambient. room temperature is only 10 degrees below the intended tank water temp. This in itself will more quickly cause malfunction of heaters as they are having to do basically the impossible. A room heater would help here. I kept my fish room at 70F during the winter months, so the tank heaters only had to maintain the temp six to eight degrees above the room temp.

Do you think 2 x 150w would be ok?
It sounds like im going to have to lift the house temps at night. Would lifting house temp to 20c (68F) suffice?

 

[Emeraldtarpon]

Ok, sorry Byrron...just catching up LOL.
2 x 250 to 300w really?
Im currently running a 3ft-130L tank with a Fluval T 200w heater in the above conditions (8-10c at night) and its coping very well (temps staying stable -/+1c at night).
2 x 250 to 300w seems a bit excessive to me...im basing that on my 200w heater's performance in the 3ft?

 

[Byron]

Ok, sorry Byrron...just catching up LOL.
2 x 250 to 300w really?
Im currently running a 3ft-130L tank with a Fluval T 200w heater in the above conditions (8-10c at night) and its coping very well (temps staying stable -/+1c at night).
2 x 250 to 300w seems a bit excessive to me...im basing that on my 200w heater's performance in the 3ft?

I speak from considerable experience. The heater is the one piece of equipment I will never scrimp on, because a malfunctioning heater can kill a tank of fish overnight. The filter can fail, no problem (unless the tank is in trouble anyway), and the light can fail, no problem. But not the heater in cold seasons. My high-end heaters in 200w and 250w worked without a hitch since I got them in the mid 1990's. But I had two or three maybe 50w heaters that failed in smaller tanks.

 

[Emeraldtarpon]

I speak from considerable experience. The heater is the one piece of equipment I will never scrimp on, because a malfunctioning heater can kill a tank of fish overnight. The filter can fail, no problem (unless the tank is in trouble anyway), and the light can fail, no problem. But not the heater in cold seasons. My high-end heaters in 200w and 250w worked without a hitch since I got them in the mid 1990's. But I had two or three maybe 50w heaters that failed in smaller tanks.

Ive noted from your posts Byron that you are a very experienced aquarist and i always appreciate your replies because of this.
If i'm to be honest, i think i might be questioning your advice for an unrelated matter....
Running costs
Your advice kinda shocked me a bit and i started to worry about running costs...(what sort of 'spike' will this put on my power bill, can i afford to run this system etc).
I suppose ive got my heart set on this and your advice, although absolutely correct, sort of gave me that sinking feeling...hence the "rejection" i just displayed.
I do apologise.