I understand that, but it dosent answer my question. While you can add 2 smaller heaters or even several, thats the safety precaution. I got it. But how will adding a larger wattage of heaters increase or maintain the temperature in the display better when the throughput remains the same? Thats why I tried to lay it out a bit more logically. But I must have failed if the science teacher fails to understand me :sad1:
A question on heater size for you smart people
- Thread starter DGonci
- Start date
I understand that, but it dosent answer my question. While you can add 2 smaller heaters or even several, thats the safety precaution. I got it. But how will adding a larger wattage of heaters increase or maintain the temperature in the display better when the throughput remains the same? Thats why I tried to lay it out a bit more logically. But I must have failed if the science teacher fails to understand me :sad1:
Conesus_Kid
Premium Member
No, you haven't failed yet.
First, let's agree that since your return pump is moving water so quickly, we might as well just use the total system volume for our discussion. Also, the numbers I'm using aren't real, but they make the examples more clear.
Here we go:
Joules are units of energy.
It requires a certain number of joules to raise the temperature of water one degree (either C or F, doesn't matter).
Watts are units of power (energy expended over time)
1 watt= 1 joule/second
If I need 100 joules to raise my water to the desired temperature...
-a 1 watt heater would take 100 seconds to do this
-a 5 water heater would take 20 seconds to to it
-a 25 watt heater would take 4 seconds
- and a 100 watt heater would take 1 second.
Adding more heater wattage to a system allows it to bring/maintain the water to desired temperature more quickly. It's not necessarily "better", but it is faster. In fact, if the heater wattage is too small, it can't keep up with the demand for heat, and won't be able to maintain the desired temperature. (Imagine heating a hot tub with an aquarium heater.)
I think that will answer your question. If not, give me one more shot at it!:fun2:
OK scott I think your making some progress..:idea:
I understand the energy used to heat up the water. I was actually pretty good in the sciences, then became a dumb army guy...:rollface:
1. Even if the water is flowing through pretty fast, its still entering/leaving the display at a static rate correct?
2. With a static flow rate how will a larger wattage of heat change how fast the display will heat up?
3. Last theoretical question for you then, Lets say you keep the flow troughput static at 700gph, and go with an even 400w for heat. Would you still be able to maintain the heat equally in a 75G display as a 120G display?(Ok I will concede that the 120g would lose heat faster due to larger surface area etc, however the cooler water would still return at the same rate to the sump)
Let me get your best answers on those so I can play tennis and hit it back then.
I understand the energy used to heat up the water. I was actually pretty good in the sciences, then became a dumb army guy...:rollface:
1. Even if the water is flowing through pretty fast, its still entering/leaving the display at a static rate correct?
2. With a static flow rate how will a larger wattage of heat change how fast the display will heat up?
3. Last theoretical question for you then, Lets say you keep the flow troughput static at 700gph, and go with an even 400w for heat. Would you still be able to maintain the heat equally in a 75G display as a 120G display?(Ok I will concede that the 120g would lose heat faster due to larger surface area etc, however the cooler water would still return at the same rate to the sump)
Let me get your best answers on those so I can play tennis and hit it back then.
Conesus_Kid
Premium Member
1. Yes.
2. I would say that even though 700 gph is a static rate, it's moving so quickly that there's no temperature difference between the display and the sump. So, in essence, a heater in a 30 gallon sump on a 120 G display pushing 700 gph would be the same as the heater in a 150 gallon display with no sump.
If the return pump were very slow, like 5 gph, then what you're talking about would be a factor. In that case, there would probably be a temperature differential between the sump and display b/c the display would cool more quickly than the return pump could bring the warmed water up to the display. In other words, the heater would warm the water faster than the return pump could send it.
In our reef tanks, the heaters can't even come close to keeping up with the return pump. The water's moving so quickly that it's all the same temperature, whether it's in the display or sump.
3. In your example, the 400 w heater would have to be on longer for the 120 gallon tank, since a bigger volume of water requires more energy to bring it up to temperature. In other words, if it takes 150 joules of energy to add enough heat to the 75 gallon, it would require more (~240 joules) energy to add enough heat to the 120 gallon to the same temperature.
If we were using the same wattage heater on both, the one on the 120 G would have to run longer to account for those extra joules. (Remember: 1 watt= 1 joule/second. We would need more of those "seconds" to provide the tank with the extra joules).
Are we getting closer?
2. I would say that even though 700 gph is a static rate, it's moving so quickly that there's no temperature difference between the display and the sump. So, in essence, a heater in a 30 gallon sump on a 120 G display pushing 700 gph would be the same as the heater in a 150 gallon display with no sump.
If the return pump were very slow, like 5 gph, then what you're talking about would be a factor. In that case, there would probably be a temperature differential between the sump and display b/c the display would cool more quickly than the return pump could bring the warmed water up to the display. In other words, the heater would warm the water faster than the return pump could send it.
In our reef tanks, the heaters can't even come close to keeping up with the return pump. The water's moving so quickly that it's all the same temperature, whether it's in the display or sump.
3. In your example, the 400 w heater would have to be on longer for the 120 gallon tank, since a bigger volume of water requires more energy to bring it up to temperature. In other words, if it takes 150 joules of energy to add enough heat to the 75 gallon, it would require more (~240 joules) energy to add enough heat to the 120 gallon to the same temperature.
If we were using the same wattage heater on both, the one on the 120 G would have to run longer to account for those extra joules. (Remember: 1 watt= 1 joule/second. We would need more of those "seconds" to provide the tank with the extra joules).
Are we getting closer?
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