A question on heater size for you smart people

My question Gary is do you need to heat the sump size or the display tank? After all 200W would heat up the sump size fairly quickly in a 30G. WIth the same flow rate I think the difference wouldnt be that much in time to heat it up.

both together
 
Ok, let me try this a different way then because I disagree with a couple of things. First while I do agree that it is one body of water, i disagree that you are heating the entire thing. I still say that you are heating the water in the sump, which you in turn then pump the heated water up to the display. If you turn off the pumps the display gets cold.If I have larger wattage of heaters in the sump, it will heat the water in the sump up faster, however it will still only heat it up to 80 degrees, or what ever the setting is at. At this point, even though it is ongoing, the return pump is pumping the warmed water up to the display where it is mixing with the display and evening out the display temperature.

I think a better question would be: Can the wattage of the heaters keep up with the throughput of the return pump?

I know this is against alot of what we currently do, but I gave it a shot in my tank. I have a 120G with a 30G sump. I am using a 700 gph return and only have 2 100W heaters in the sump and have no issues heating the display. And the heaters are not on any more that I can tell compared to when I had a 3rd 300w heater in there. It just made sense to me, and wanted to see what others thought.

In another area, think of inline or tankless water heaters for the home. They use less enrgey since they are only heating the water that pass through instead of the whole body of water in the tank.
 
my display is a 55 with a 30 sump which in accuallity is only about 15 gal. I have a mag 5 with about 4 ft head so its pushing about 300 gal per hour. That means that the sump water gets turned over about 20 times per hour (about 3 min) There is no way my heater is heating the water in my sump any hotter than my DT in 3 min. YOu need to take in the whole volume.

Tim
 
There are additional factors also - for example, when I replaced my current skimmer with a recirculating pump with a non-recirculating skimmer my heaters started running more. turns out the current recirculating pump puts off a lot of heat.

point is that there is more than just heaters heating the tank which is why some people can use lower wattage heaters than others.
 
The logic that you're just heating the water in the sump is a bit flawed. With your return rate of 700 gph, you're basically emptying that 30 gallon sump every 2.5 minutes. There's no heater in the aquarium trade that can keep up with that!

That makes sizing the heater to the return pump a moot point. Any return pump that we use moves the water to the display so quickly, that you are, in fact, heating the entire volume of water (sump + display).

The reason tankless water heaters cost less to run is that they don't heat water that's just sitting in a tank in your basement. They only heat the water that you're using at the moment. It doesn't take any less energy to bring a certain volume of water to a certain temperature. It just does it in a less wasteful way.

HTH
 
The reason tankless water heaters cost less to run is that they don't heat water that's just sitting in a tank in your basement. They only heat the water that you're using at the moment. It doesn't take any less energy to bring a certain volume of water to a certain temperature. It just does it in a less wasteful way.
exactly.
Heated water sitting in a hot water tank loses heat while it's being held. The electricity used to keep that water heated to a certain temp (while it's being held) is what can be saved by using a tankless heater.
 
what's wrong with your 300w heaters?
As for heater recommendations I can't help.
I haven't purchased a heater in over a decade. I can't remember what brand I'm running and my heaters themselves are fully encrusted so I can't tell what they are.
 
what's wrong with your 300w heaters?
I haven't purchased a heater in over a decade. I can't remember what brand I'm running and my heaters themselves are fully encrusted so I can't tell what they are.

Well we are going to have to figure out what brand being that they will last over 10 years!
 
Well I run 2 300 watt finnex heaters hooked up to my ACjr. Both are in the sump. One set to keep the tank at temp and the other just below that incase the 1st one breaks. The temp in the DT and the sump (90/30) is the same +- .2 deg. There is about 110 gallons total with a Mag 9.5 pushing about 5' head. Basiclly there is only one 300 watt heater for the whole tank.
 
Any way you can get your AC Jr to show when and how long the heaters are on? Would Aquanotes be able to do this? I'm savy with setting them (AC Jr.s) up, but I don't run Aquanotes.
 
Slightly OT, but I'm using an Ebo-Jager that was my first heater for my FW tank. It's going on 13 years old now and believe me, it hasn't been babied. I don't think I'd ever get anything else.

OK, back to the regular scheduled discussion and back to work for me!
 
I'll second that. My Ebo's are 5 years old. Haven't even seen them for 3 years. They've been in the overflow of the display. Still kickin', temp stays consistent, keeping seasonal fluctuations in mind :thumbsup:
 
400 watts of heat for a 120 with a sump is fine given you have a big enough return pump (also take into effect the winter as it is colder in the house so more power could be necessary). as previously stated, you are heating up your entire system. if you already have more, keep them. it will just heat the water in your sump faster.. your tank will NOT overheat or underheat if you have a bit more in terms of heaters. again, noted before, its going to take the same amount of energy to heat the water
 
Here is a graph from my RKE. I think I have it logging every 15 minutes. I have 600 watts heating right around 115 gallons of water. The heaters are on a lot now because the basement is around 60 degrees. The heat in the house is also turned down during the day, which is shown with the heaters being on more during the day.
 

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First off, let me clarify, I am not asking wheather this will work for me or what I need to do, which is what some of the posts seem to imply. I am just trying to ask a few off the norm questions about what we do. Forgive me for that, the Army has me off at training in a somewhat remote location with not alot to do at night.

Let me ask a few questions this way....

Lets just for simplicity go with 4 wats per gallon for a standard for determining heater size.

With that can we agree to the following:
Tank A = 75G tank needs 300W
Tank B = 90G tank needs 360W
Tank C = 120G tank needs 480w
Tank D = 180G tank needs 720w
Does that seem fair enough?

So now lets take a system and say we use the same sump/return for each of the above systems, say a 30G sump holding about 25G of water and 700gph return, although it really doesnt matter the size just so they are identical in each set up. While I understand that you would have a much larger sump on a 180, just bare with me. :sad2:

So we have the following total water volumes and additional heater requirements:
Tank A = 100G / 400W
Tank B = 115G / 460W
Tank C = 145G / 580W
Tank D = 205G / 840W

Now based on EVERYONES logic if I place all the heaters required for each system in the sump each tank will heat up since you are using the appropiate size heater for the total water volume. Correct? Or am I misunderstanding you?


Now in each of the above systems the flow is the same in/out of the sump...Agreed?

So now can someone please explain to me how adding more heaters to a sump will alter the amount of warm water entering the display? Since the return pump is a static variable at 700gph, my argument is that no matter how many heaters you have in the sump the EXACT same amount of heated water will enter the display. IMO more heaters just means that the water in the sump will just heat up faster, however the water WILL NOT enter the display at any greater rate. Which somewhat goes back to my original premise of having an appropiate size heater for the amount of water passing through it.

Lets your arguments...bring em! :blown:
 
Bottom line: You're not going to save money by using smaller (or larger) heater wattages. As Gary mentioned previously, it requires a certain amount of energy to raise the temperature of your water one degree. If you choose heaters with smaller wattages, they will use less energy, but will need to stay on longer to bring the water up to temp. If you choose heaters with larger wattages, they won't stay on as long, but they use more energy to bring the water up to temp in that shorter time frame.

My advice: Get two heaters of equal wattage. Make sure that one of them alone is large enough to fulfill your tank's temperature requirements, but not large enough to boil your aquarium if it gets stuck on. Set one a couple of degrees higher than the other one, and run them both on a temperature controller (Ranco or and AC Jr./AC 3). This way you have a backup and a heater malfunction won't cook your fish and corals.
 
Adding more heaters is a safety measure, not a way to add more heated water to the display. Basically, the return pumps we use move water so quickly that all of the water in the sump and the display will be (pretty much) the same temperature. It's not like it's sitting in the sump, getting warmed, then getting pumped to the display.
 
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