Best heaters to use with controller?

iwishtofish

iwishtofish

Active member
My two 300w heaters aren't keeping up! I need to upgrade, and I'd like to use a controller (probably RKL1). Need advice!!
 
How much water you have? I am using 400w (2 x 200w ehiems) in a system with about 130g total. It does great for me. The big variable however is what is you abmient temp in your house? Do you have A/C? What kind of lighting are you using?
 
bamf25 said:
How much water you have? I am using 400w (2 x 200w ehiems) in a system with about 130g total. It does great for me. The big variable however is what is you abmient temp in your house? Do you have A/C? What kind of lighting are you using?
Click to expand...

I have a 75g tank with a 40b sump. I can't figure things out. I have a 300w Eheim Jager set high enough that it never turns off, and a Finnex 300w "digital" set to 80 degrees. There is central A/C in the house, but the basement (where the tank is) is controlled by the thermostat on the main floor above. The basement temperature can vary a couple degrees on either side of the thermostat setting upstairs. Sometimes when the basement air temperature drops to 67, the tank temp nears 77 (sometimes cooler). Sometimes when the A/C doesn't run as often because the day is a little cooler, the basement gets warmer than the upstairs, and the tank with lights on nears 80 degrees.

The tank is a peninsula-style open-top with a LOT of surface agitation. The stand is currently open. The lights are a 6-bulb, 36" Tek T5 fixture, currently well above the water since I have no corals.

I'd love more ideas and advice!
 
That should b plenty for your water amount. And btw 77 degrees is fine for a reef. From 76-82 is safe imo
 
sjm817 said:
What do you use for a return pump?
Click to expand...

Scott, it's a Mag 9.5, but it's probably only about 300-350 gph at the tank due to reactors, fuge, etc.

tozzi said:
That should b plenty for your water amount. And btw 77 degrees is fine for a reef. From 76-82 is safe imo
Click to expand...

Yes, but is the 2 - or maybe even sometimes 3 - degrees variation good to have over the course of a day?
 
Just checking that you are using a water cooled pump which helps with the heating. You are SURE both of those heaters are working? They are hot to the touch most of the time?
 
sjm817 said:
Just checking that you are using a water cooled pump which helps with the heating. You are SURE both of those heaters are working? They are hot to the touch most of the time?
Click to expand...

The tank receives passive heat from the Mag 9.5, the skimmer pump, a mini-jet, a Koralia 4, and a Koralia Magnum 7. I know I have seen heat coming off the Eheim Jager heater when the light is on, and I remember the Finnex heater feeling hot when I was moving it.

All I can think of to do is to get a controller with a temp probe to put in the DT, crank both heaters to the max, and give that a try. The Finnex is supposed to have an electronic memory to keep it at the proper setting when power is lost and resumed, but I'm not sure I trust that.
 
Doesn't sound right. 2 x 300W should have no problem keeping that system up to temp. A controller wont fix that if they are always on and cant keep up.
 
sjm817 said:
Doesn't sound right. 2 x 300W should have no problem keeping that system up to temp. A controller wont fix that if they are always on and cant keep up.
Click to expand...

I know. :( I'm certain the Eheim Jager is on all the time because of the light, and the Finnex is set to 80. Maybe the Finnex isn't accurate, although the tank gets hotter than I want when the room temperature rises just a few degrees.

My sump before the second heater:

sump01.jpg


How the two heaters are set up now:

heaters_03.jpg


The refugium baffle is really tall, and spills over a good ways into the return compartment.
 
How many gallons do you evaporate a day? You get a little over 8,000 BTUs of cooling per gallon of seawater evaporated. Lets call your total system volume 100 gallons. You have 850 pounds of water, so if you pull 850 BTUs from the tank, you get a drop of 1 degree F. 1 gallon of evaporation equates to about 9 degrees of pulldown in your system that the heaters have to make up.

So if you evaporate 2 gallons per day that is about 16,000 BTUs lost or about 666 BTU/hr.

If you evaporate 5 gallons per day that is about 40,000 BTUs lost or about 1666 BTUs per hour.

You have 600W worth of heaters, capable of 2049 BTU/hr. so even at an evaporation rate of 5 gallons per day and other smaller loses (convection, conduction, radiation) your heaters should be able to keep up.

Secondly, you really should be running those heaters from a dedicated controller such as a Ranco. I would NOT run my heaters without a controller and would opt for a dedicated controller and NOT a reef controller.
 
BeanAnimal said:
How many gallons do you evaporate a day? You get a little over 8,000 BTUs of cooling per gallon of seawater evaporated. Lets call your total system volume 100 gallons. You have 850 pounds of water, so if you pull 850 BTUs from the tank, you get a drop of 1 degree F. 1 gallon of evaporation equates to about 9 degrees of pulldown in your system that the heaters have to make up.

So if you evaporate 2 gallons per day that is about 16,000 BTUs lost or about 666 BTU/hr.

If you evaporate 5 gallons per day that is about 40,000 BTUs lost or about 1666 BTUs per hour.

You have 600W worth of heaters, capable of 2049 BTU/hr. so even at an evaporation rate of 5 gallons per day and other smaller loses (convection, conduction, radiation) your heaters should be able to keep up.

Secondly, you really should be running those heaters from a dedicated controller such as a Ranco. I would NOT run my heaters without a controller and would opt for a dedicated controller and NOT a reef controller.
Click to expand...

Thanks for weighing in, BeanAnimal. I believe I evaporate 2 or more gallons/day.

Where can I find a Ranco controller? I take it the temp probe sits in the DT?

Do you think it possible that the fact the room can get quite cool and and there is much air flow all around the tank and sump could contribute to my tank not staying up to temp? Should I invest in better/larger heaters to put on the controller? I was thinking of using the RKL so I could control a cooling fan, as well, if the temp rises when the room gets hot.
 
if both heaters(600w) are on for an extended amount of time, i think the temp would easily exceed 80degrees in a 100g net tank.

i have a 500w titanium and when i was cycling, i kept it at about 85 degrees and it had no problems maintaining that. this is a 200g+ net system. without the heater, my water temp was sub 70 degrees.
 
geaux xman said:
if both heaters(600w) are on for an extended amount of time, i think the temp would easily exceed 80degrees in a 100g net tank.

i have a 500w titanium and when i was cycling, i kept it at about 85 degrees and it had no problems maintaining that. this is a 200g+ net system. without the heater, my water temp was sub 70 degrees.
Click to expand...

I have no explanation! It seems when I turn the Ehiem Jager up higher, my tank can get too warm if the room is warmer. My best guess is the combination of evaporative cooling, lower flow, and open design must be powerful factors in the tank retaining heat. ????

I want to try the controller with the heaters, but I'm not sure I trust the Finnex to retain it's temp setting (because it has a digital thermostat vs a mechanical one). Can you recommend good heaters to use with a controller?
 
The Eheims are good. The Finnex is not. The built in temp controller is junk and resets itself to 80 (which can be very far from 80) when power is lost. You want the heaters set just a bit higher than the external controllers temp.
 
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