Heating the 90gal tank questions

[Drewbe147]

I have a ehiem jager 200watt heater thats set on 77 and I bought a 2 pack of cheap digital thermometers. My heater rarely comes on except night time when my lights are off. My lights are 2 fluval marine 48" led A3985 is the model. The way my canopy is on the tank the lights sit right on the rim of the tank. Idk how much i trust the cheap thermometers ($8 for 2) but they read around 81-82 thoughout the day due to the light heating the tank. Night temp doesnt drop below the heater setting at 77 and I run a fuge light in the sump overnight. The back half of the tank inside the canopy has glass lid as well. Is this too hot? Should i remove the back half glass sections that cover the back? I have 2 koralias 1150 powerheads pointing up breaking the surface as well as my return lines breakin the surface to help evap an cooling. My house temp stays between 71-74°. This is how the previous owner had it set up and I figured I would keep the glass on the back half being theres a 3" gap at the back of the canopy and i plan to have wrasses thatll jump. I don't have room for a chiller. Should I just get a screen for that 3" gap around the backside of the canopy?

 

[lapin]

77 to 82 is a pretty big jump every day. Do you have a digital meat thermometer to double check the high and low? Some livestock may not like this big jump. You might screen a portion, replacing the glass or have a fan blow air thru the lights during the day.

 

[mcgyvr]

In general the recommended temperature range is 76-83deg F...
I would not be concerned with the temperatures you are measuring assuming they are accurate..

I would not fully cover a tank without a sump so as to allow proper gas exchange.. (Co2/oxygen/nitrogen,etc...) but would leave some decent gaps.

 

[Drewbe147]

[MENTION=40980]McGyver[/MENTION] I have a sump under the cabinet. I also don’t know how true the readings are on this cheap digital thermometer is. Any recommendations on a accurate one? The canopy on the tank has about 8” of headspace in there from top of the water to top of the canopy. Back side of canopy has 3” gap all the way across the back of it. The glass on the top of the tank only covers the back half not a full cover but its only like a inch off the water prolly trapping more heat. So recommendations on accurate thermometer and should I just remove that glass covering the back half of the tank allowing more to exit the back of the canopy?

 

[Drewbe147]

[MENTION=367859]lapin[/MENTION] this was my concerns as well. Is there a small enough fan to fit in that canopy? Like i said not much headspace between water and the top. Or run a fan at the sump? When i open the canopy to either feed or turn lights off u can feel some heat radiating out of the canopy like its somewhat trapped in there. I run my blues for an hour then whites 10hrs then blues again for an hr so 12hrs of lighting. I only have a pair of clowns and some CUC in there right now but before I add anything to it I want to ensure my temp isnt going to be a problem

 

[mcgyvr]

Ice water calibration is a good starting point to see how they do..

Fill a glass with ice cubes, then top off with cold water.
Stir the water and let sit for 3 minutes.
Stir again, then insert your thermometer into the glass, making sure not to touch the sides.
The temperature should read 32°F (0°C). Record the difference and offset your thermometer as appropriate.

 

[Drewbe147]

Did the ice calibration twice on same thermometer. First time my probe wasnt touching sides but was on a piece of ice in the cup an measured at 33.3°. The second test after the 3min mark i removed half the ice to have available space in the water where the probe touched nothing but water and it measured at 35°. So im between 1.3 and 3 degrees off or avg 2.1. Which off the avg of that means when im reading 82 its truely only 80 then? So my temp swing would then only be between 77-80?

 

[mcgyvr]

Sounds about right there..
All good IMO..

 

[Crooked Reef]

Do you have a LFS that would let you test it in their tanks vs. one of their thermometers? I would feel more comfortable knowing it was calibrated to a temperature closer to what I want to run my tanks at. Same reason I use calibration fluid for my refractometer instead of ro/di.

 

[Drewbe147]

[MENTION=38412]mcgyvr[/MENTION] thanks for all ur help. [MENTION=311968]Crooked Reef[/MENTION] I might do that I plan on going to the LFS tmrw and ordering a few wrasses and picking up some snails to add to the CUC

 

[lapin]

[MENTION=367859]lapin[/MENTION] this was my concerns as well. Is there a small enough fan to fit in that canopy? Like i said not much headspace between water and the top. Or run a fan at the sump?

What you might do is look for 2 small usb computer fans. They are about 3" square. You can cut a hole in each end of the hood, or if in back, at each end of the back. Mount them inside with one sucking air in and one blowing air out.

 

[Drewbe147]

[MENTION=367859]lapin[/MENTION] thanks Ill look some up and add that to the todo list. Appreciate everyones help and advice ty all

 

[homer1475]

Ice water calibration is a good starting point to see how they do..

Fill a glass with ice cubes, then top off with cold water.
Stir the water and let sit for 3 minutes.
Stir again, then insert your thermometer into the glass, making sure not to touch the sides.
The temperature should read 32°F (0°C). Record the difference and offset your thermometer as appropriate.

This is the proper way to calibrate a meat thermometer. Least it was how I was taught at the CIA.