ReefKeeperLight, heater and temperature fluctuations

[pomoev]

Hi. I am using RKL with 50w Eheim Jager in my 20gallon Elos mini system. During the day, while room temperature is about 70F, RKL keeps tank temperature at 77±0.1. At night when the room temperature goes down to 60F the heater probably can't keep up and drops the tank temperature to 73-74. I replaced a 50w eheim with 200w Tetra and still it's only 74F in the morning. Is there a way to fix it? In my understanding 200w should be more than enough...

 

[mtraylor]

The RKL cannot hold the temp of the aquarium to the desired remp by itself. In your case, the aquarium is fluctuating via the ambient temp in the house.

First thing i would do is set the desired temp you want to hold on the heater itself. Let the heater do the job and work. Then set a fail safe on the RKL to turn on/off the heater in lets say .4 degrees or so from the temp set on the heater. You will have to play a bit to get desired results.

Sounds like to me that heater isnt even kicking on at night. You may have setup config incorrectly. 200 watt is mor than enough.

I have 2-300watt on my 255 reef. Total volume of 355gallons. It does fine.

 

[pomoev]

I heard there is some logic in heater internal controllers that prevents heaters from raising temperature too quickly. I'm curious, can it somehow interfere with quick ambient temperature decrease?
Anyway, I just plugged the heater into another socket and reconfigured it. Let's see how it goes.

 

[mtraylor]

Never heard of that, but ambient temp in a house doesn't change that fast anyway (usually). The way heaters work is its either on or off. Pretty basic logic. Depending on the wattage of the heater will determine how fast or slow the water is heated up calculated with the flow of water. Thats about it.

If you adjust the way I explained you will have no issues. One way to start out would be to plug it in an unprogrammed outlet and let the heater do its job. You will get a graph of where the heater is keeping the temp steady. You dont need the controller. Use the controller as a back up as I stated. Then program the outlet right outside the range of the heater just in case the heater controller fails. You can also put an alarm on that outlet so if the controller does start controlling the temp, then you will know there is something wrong with the heater.

Good luck.

 

[pomoev]

Never heard of that, but ambient temp in a house doesn't change that fast anyway (usually). The way heaters work is its either on or off. Pretty basic logic. Depending on the wattage of the heater will determine how fast or slow the water is heated up calculated with the flow of water. Thats about it.

If you adjust the way I explained you will have no issues. One way to start out would be to plug it in an unprogrammed outlet and let the heater do its job. You will get a graph of where the heater is keeping the temp steady. You dont need the controller. Use the controller as a back up as I stated. Then program the outlet right outside the range of the heater just in case the heater controller fails. You can also put an alarm on that outlet so if the controller does start controlling the temp, then you will know there is something wrong with the heater.

Good luck.

I started with just using a heater without rkl. None of my heaters could keep the same temperature for 24h, it was always 3-4 degrees lower at night. Is it normal for heaters? Or should I just get a new one?

 

[mtraylor]

Post some pictures of your setup. Would like to see total water volume and where you have the heaters and where you have the temp prob from the RKL.

 

[pomoev]

Post some pictures of your setup. Would like to see total water volume and where you have the heaters and where you have the temp prob from the RKL.

Heater is in the sump, temp probe is right next to the return pump. 20 gallon cube on top, roughly 3-4 gallons in the sump inside the cabinet.

My guess is 50w eheim too weak and 200w tetra is just old and not working as intended.

 

[mtraylor]

Yeah the 50w is a little undersized for that aquarium. If you had 4 to 5 degrees ambient room temp swing, it may have been ok.
Your ask is to have a heater that will keep your aquarium at say 78 degrees, when there is almost 20 degrees difference in ambient temperature.

Looking at your aquarium setup, you may not be able to get anything bigger than a 100watt heater in the sump. So I would go with a 100watt eheim,
and to be honest I would probably run 2 of them. They will work more efficient at keeping your temp steady. Have them backed up by your controller
so no issues. If one goes bad, then you will have one heater in there that can pretty much handle the load by itself until you replace them.

 

[pomoev]

Yeah the 50w is a little undersized for that aquarium. If you had 4 to 5 degrees ambient room temp swing, it may have been ok.
Your ask is to have a heater that will keep your aquarium at say 78 degrees, when there is almost 20 degrees difference in ambient temperature.

Looking at your aquarium setup, you may not be able to get anything bigger than a 100watt heater in the sump. So I would go with a 100watt eheim,
and to be honest I would probably run 2 of them. They will work more efficient at keeping your temp steady. Have them backed up by your controller
so no issues. If one goes bad, then you will have one heater in there that can pretty much handle the load by itself until you replace them.

Thank you!

 

[mtraylor]

Np. Your aquarium looks nice btw.

 

[ADAM]

Are temp probe and heater in the same sump section? If so I would separate them with the sensor in the 1st chamber and the heater in the return section. Now the ambient temp is affecting the tank however with both probe and heater in the same chamber the heater may not be running enough to due to its warming the probe faster than it can heat the tank. The probe in chamber 1 will only measure the return water temp and then heating will occur downstream until the rerun water measures at temp. Also with the RKL and probe controlling the temp you will want to set the temperature on the heater itself a few degrees higher so that the heater itself doesn’t cycle off when the controller wants heating to occur. Keep both probe and heater in the same tank, either the display or sump. Starting out I didn’t think about it and had the heater in the overflow and the sensor/ probe in the return area of the sump.....well the return pump failed (no biggie, but should’ve had a backup), ordered another, next day went to adjust the powerheads and WOW! The tank was hot as hades. With return pump off and the sensor in the sump the probe was calling for heat continuously, so the heater in the internal overflow was constantly heating.

I’d think with good placement the wattage of heater(s) would be enough with the right placement for you setup. If not maybe put a smaller heater on a timer to help back up the big heater during the night hours.

 

[pomoev]

Are temp probe and heater in the same sump section? If so I would separate them with the sensor in the 1st chamber and the heater in the return section. Now the ambient temp is affecting the tank however with both probe and heater in the same chamber the heater may not be running enough to due to its warming the probe faster than it can heat the tank. The probe in chamber 1 will only measure the return water temp and then heating will occur downstream until the rerun water measures at temp. Also with the RKL and probe controlling the temp you will want to set the temperature on the heater itself a few degrees higher so that the heater itself doesn’t cycle off when the controller wants heating to occur. Keep both probe and heater in the same tank, either the display or sump. Starting out I didn’t think about it and had the heater in the overflow and the sensor/ probe in the return area of the sump.....well the return pump failed (no biggie, but should’ve had a backup), ordered another, next day went to adjust the powerheads and WOW! The tank was hot as hades. With return pump off and the sensor in the sump the probe was calling for heat continuously, so the heater in the internal overflow was constantly heating.

I’d think with good placement the wattage of heater(s) would be enough with the right placement for you setup. If not maybe put a smaller heater on a timer to help back up the big heater during the night hours.

Thanks for the reply.
Yeah, the heater is in the sump in the small chamber, the probe is by the return pump. I think I just need a good heater.

 

[Jason777]

Agree with @ADAM you will need to move your temp probe upstream of the heater to get the RKL to maintain a temp. With the temp probe downstream I suspect the heater is cycling on for a very short period and the RKL senses a 0.2° rise and turns it off before it makes a significant rise in total volume temp.

 

[pomoev]

Agree with @ADAM you will need to move your temp probe upstream of the heater to get the RKL to maintain a temp. With the temp probe downstream I suspect the heater is cycling on for a very short period and the RKL senses a 0.2° rise and turns it off before it makes a significant rise in total volume temp.

Right, I missed this point in Adam’s post. Will try it, thanks!