Heater Set Up for Large Tanks

[MonarchzMan]

I am running two tanks that are roughly 400 gallons (when sumps are included - each tank is ~8' x 2' x 3'). One tank is a reef tank and the other is an African cichlid tank. I got an Apex to run the reef tank and recently got the necessary modules to also be able to run the cichlid tank. Where I am stuck, at the moment, is where it comes to heaters and solutions for them. I have read that, under ideal situations, I should have two heaters in a tank to extend the life of the heater and to have a back up just in case one dies. This is all well and good except for the fact that these are massive tanks. As best as I can tell, a couple of 1000w heaters would be best except for the fact that it would potentially pull too many amps for any of the EB8 outlets. So I thought about two 800w heaters, but having both of those plugged into an EB8, and I'd be nearly the 15 amp limit of the EB8. And that would be just running the two heaters and nothing else. Currently, the EB8 for the reef tank runs about 12 amps when the lights are on (MH) and the freshwater EB8 runs about 3 amps. Long term, I would like to replace the metal halides with Kessils for energy saving (and Apex control), but that is quite an investment for the moment. Even so, adding in the heater would likely overwhelm the system. Fortunately, for the moment, it seems as though the MH provides enough heat that I don't really need a heater (the chiller goes on often). But I will want one soon. It is not as critical for the freshwater tank to have exact temperatures, but I would at least like to keep the tank above 78 (currently sitting around 76-77). I'd like to have heat on both tanks before winter starts up.

Any suggestions for how to deal with this heating situation? Both in terms of set up with the Apex and with what particular heaters I should look into. Thanks!

[iamchadster]

I am running two tanks that are roughly 400 gallons (when sumps are included - each tank is ~8' x 2' x 3'). One tank is a reef tank and the other is an African cichlid tank. I got an Apex to run the reef tank and recently got the necessary modules to also be able to run the cichlid tank. Where I am stuck, at the moment, is where it comes to heaters and solutions for them. I have read that, under ideal situations, I should have two heaters in a tank to extend the life of the heater and to have a back up just in case one dies. This is all well and good except for the fact that these are massive tanks. As best as I can tell, a couple of 1000w heaters would be best except for the fact that it would potentially pull too many amps for any of the EB8 outlets. So I thought about two 800w heaters, but having both of those plugged into an EB8, and I'd be nearly the 15 amp limit of the EB8. And that would be just running the two heaters and nothing else. Currently, the EB8 for the reef tank runs about 12 amps when the lights are on (MH) and the freshwater EB8 runs about 3 amps. Long term, I would like to replace the metal halides with Kessils for energy saving (and Apex control), but that is quite an investment for the moment. Even so, adding in the heater would likely overwhelm the system. Fortunately, for the moment, it seems as though the MH provides enough heat that I don't really need a heater (the chiller goes on often). But I will want one soon. It is not as critical for the freshwater tank to have exact temperatures, but I would at least like to keep the tank above 78 (currently sitting around 76-77). I'd like to have heat on both tanks before winter starts up.

Any suggestions for how to deal with this heating situation? Both in terms of set up with the Apex and with what particular heaters I should look into. Thanks!

A relay plugged into the EB8 might work for the heaters if the amps are too high for plugging into the EB8 directly.

[RussM]

An EB4 would be better suited to running larger heaters. There are (3) 8A outlets and one 12A outlet. If used on a dedicated 15A or 20A circuit, you could one large 1000w heater on the 12A outlet and some small devices on the remaining outlets. Or use 2 medium-large 800w ones.

[zombie]

With halides, you definately do not need 2000 watts of heaters. For redundancy, I would do a 400 watt heater for each tank controlled by the apex with the thermostat set 1 degree higher than operating temp. Then have 1 more 400 watt heater for each tank plugged into the wall that is set 0.5 degrees below the apex heaters.

You might be an engineer if...You have no life and can PROVE it mathematically.

[MonarchzMan]

The cichlid tank is not on MH (just T8 flourescents). Would that still require a 400w or would I need to shoot for a bigger one? And if we switch over to Kessils for the SW tank, would we need to upgrade the heater on that tank?

[Alain B]

Kessil do not push much heat in a tank . I have 3 radions at full bore on my 225 gallons system and i still need to heat to water even during the daylight hours . I use 2 x 500 watt heater on a 4 hours alternating schedule with a high heat outlet just in case they might need to come ON both at the same time to warm up the tank . For this time of the year its getting colder outside and they run often .

Alain

[zombie]

The cichlid tank is not on MH (just T8 flourescents). Would that still require a 400w or would I need to shoot for a bigger one? And if we switch over to Kessils for the SW tank, would we need to upgrade the heater on that tank?

It depends on what temperature your house is. Rule of thumb is that 2 watts per gallon will allow you to raise the temp of the tank 10-12 degrees above ambient temperature depending on the surface area of the tank. If you have submersible pumps, half their wattage counts toward that number. A percentage of the lighting wattage can also be added as well. I use the rule of thumb 50% for halides and 25% for leds if using an enclosed canopy, or half that with an open top.

You might be an engineer if...You have no life and can PROVE it mathematically.

[iamchadster]

it has happened to me so this is why I ask but what does he do if he has a heater runaway? the heaters plugged directly into the wall would have no way to shut-off in an overtemp situation.

[zombie]

it has happened to me so this is why I ask but what does he do if he has a heater runaway? the heaters plugged directly into the wall would have no way to shut-off in an overtemp situation.

They are sized in such a way that unless the house is really hot (they can be left unplugged in summer) they will not raise the tank temp by more than 5-6 degrees above ambient room temp if they are stuck on. He could plug it into an EB8 as well with fallback on if he has the ampacity available to do so.

You might be an engineer if...You have no life and can PROVE it mathematically.

[iamchadster]

I had a 300 Watt runaway and I don't know what the temp was in the end but it felt like bathtub water. luckily it was a heater that kept my mixed new saltwater at temp.

[MonarchzMan]

These two tanks are in the biology department in the University of Mississippi. Unfortunately, the heating/cooling in the building can be somewhat variable (general rule of thumb, in the winter, it's hot, and in the summer, cold - not sure on the exact temps). If I had to guess, the temperature is kept around 72-74.

After reading up on the various LEDs, I'm leaning towards 3 AI Hydra 52s on the SW tank, and then 3 freshwater Radions XR15s on the cichlid tank. I'm assuming these will put out a little more heat (it's in a canopy, but the back is open).

Would I be good with two 500W heaters on each? And I guess in the event of a runaway, I can have the Apex send me an alert when either tank hits 81.

[zombie]

Two 400W heaters each would be plenty since you only need to raise temp by 8 degrees at most

You might be an engineer if...You have no life and can PROVE it mathematically.

[BertL]

OP, not taking away anything from folks providing advice, but if you'd like something a bit more scientific to help calculate total heating wattage needed for your specific tank, try THIS calculator over on Hamzas Reef. It may lend a bit of confidence over and above general rule-of-thumb you find on the net, and certainly mfgr recommendations on their boxes or websites. It, and a number of other calculators on that site were helpful to me during my tank research/design phase last year. ...just remember, once you input whatever variables you want to change in the calculator and get a result, you'll then need to split the total wattage recommendation into multiple heaters for backup/disaster planning, dealing with circuit load or EB outlet maximums, etc based on your design requirements (as has been discussed earlier in this thread and in others). You may then also want to check out THIS different calculator on the same site to gain an understanding what will happen should power go out, and you loose one of more of your heaters -- that may influence your design of how many, how big, and the like.

FWIW, the estimated time in the calculator to bring my initial tank up to temp when I first put water in it, ended up being within 30 minutes or so for 161gal total water volume in my system ...so, I was pretty happy after-the-fact the calculator had some basis in fact.