Temp fluctuation

[Davy Jones]

Hey guys, Ive had my apex set up since i got my reefer and i cant seem to find a way to keep my temp even semi stable, it just continuously spikes and drops and spikes and drops.







Now to combat this i set my heaters to turn on at 78.2 and shut off at 78.5 and they just turn on and shut off and turn on and shut off repeatedly throughout the day. The only time it is semi stable is when the T5 lighting is on (i have hybrid led/t5 lights so theyre only on for 4 hours a day) and the heat from that is going into the tank as well


Now i know stability is key, so is the constant shift in temp (although very small) something i should be worried about?

 

[whatchamacallit]

I'm in the same boat lol try to knee the temp at 79 but it goes from 78.9-88.9. I can watch the temp on the apex and it's always jumping around lol

 

[Randy Holmes-Farley Verified Community Expert]

I don't think you should worry at all since you are talking about small changes, but where is your temperature sensor in relation to the display tank and heaters?

 

[Randy Holmes-Farley Verified Community Expert]

I'm in the same boat lol try to knee the temp at 79 but it goes from 78.9-88.9. I can watch the temp on the apex and it's always jumping around lol

88.9?

 

[Jimmyb819]

If I'm reading that correctly then the area you have selected is only showing a swing of .4 degrees. That's nothing. As far as I know all of our aquarium heaters are running an on/off type of control, when the temp drops below setpoint the turn on, when the temp rises above setpoint they turn off. With this type of control you will ALWAYS see a sawtooth type of graph. Mine swings +- 0.5 degrees. Yours looks pretty stable to me.

The only way to improve temp stability would be to use PID control and a variable heater. Someone may be selling these already but if so I'm sure they are expensive.

 

[Davy Jones]

I don't think you should worry at all since you are talking about small changes, but where is your temperature sensor in relation to the display tank and heaters?

My temp probe and heaters are in the sump. so its possible that the display has a slightly different reading than the sump, i would assume its more stable on account of the water volume being roughly 5 times that of the sump. (and the probe and 2 heaters are all in seperate sections of the sump so i know its not just the 6 inches of water around theheater the probe is reading haha)

 

[Davy Jones]

If I'm reading that correctly then the area you have selected is only showing a swing of .4 degrees. That's nothing. As far as I know all of our aquarium heaters are running an on/off type of control, when the temp drops below setpoint the turn on, when the temp rises above setpoint they turn off. With this type of control you will ALWAYS see a sawtooth type of graph. Mine swings +- 0.5 degrees. Yours looks pretty stable to me.

The only way to improve temp stability would be to use PID control and a variable heater. Someone may be selling these already but if so I'm sure they are expensive.

yes, the swing is very minimal, ive just never had an apex before so i didnt know if all tanks had the swing in temp over the course of an hour and back or not. If this is normal for most tanks than ill stop worrying, Just wanted to get some opinions! Appreciate it everyone!

 

[Jimmyb819]

yes, the swing is very minimal, ive just never had an apex before so i didnt know if all tanks had the swing in temp over the course of an hour and back or not. If this is normal for most tanks than ill stop worrying, Just wanted to get some opinions! Appreciate it everyone!

I'd be surprised if anyone doesn't have these small fluctuations as it is typical of the type of control our heaters are using.

 

[trahelyk]

I'm a statistician, so I love pulling data like this out of the Apex and seeing how it lines up with the AMP graph. I tightened up the temperature range the other day, and now my sawtooth graph has increased in frequency but declined in amplitude. Neat-o. Also take a look at how PH swings with your lighting schedule.

One thing to keep in mind is that you're balancing the number of your heater's on/off cycles against temperature stability. If you tighten the temperature range up too much, you will have a more stable temperature, but your heater will turn on and off more frequently, and you'll shorten the life of your heater.

 

[Sabellafella]

Set the hysteresis for half hour so it doesnt go on and off as much

 

[Davy Jones]

Set the hysteresis for half hour so it doesnt go on and off as much

thats not a bad idea but i dont seem to have that option in fusion for the heater, only the lights

 

[Randy Holmes-Farley Verified Community Expert]

My temp probe and heaters are in the sump. so its possible that the display has a slightly different reading than the sump, i would assume its more stable on account of the water volume being roughly 5 times that of the sump

Yes, I think that is very likely. The display is averaging out these rapid fluctuations.