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Temp question

As you can see from my apex pic my heater is set for 77.5 to 78.0. Is this okay? Or should I set it 77.9-78.0? I don't know if its bad for the heater to kick on and off that frequently.
Thanks.

yhymemy8.jpg
 

redfishbluefish

Officer Emeritus
Officer Emeritus
I’m not familiar with Apex, but for a Reefkeeper, a tenth of a degree is too tight. I originally set my Reefkeeper for a tenth degree, and it sounded like I was at a table tennis competition. I ended up re-setting it at three tenths difference, and everything is fine.
 

kschweer

Administrator
Staff member
Officer Emeritus
Moderator
The fluctuations are not really that bad. In my opinion if you keep your temp within a very tight tolerance your corals and fish will become used to this and in the event of and emergency (power failure or heater breaks) they will be less likely to do well with any swing in temperature.
 
I don't ever hear it turning on and off so that's not a problem. And it looks like it takes about 45 minutes to heat up a half degree and then 45 minutes for temp to drop half a degree. I guess I'll just leave it as is for now. Thanks for the replies.
 
I keep mine at a .5 degree difference. Agreed on the 0.1 being too little.


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You can set the degrees really tight, but then add hysteresis to prevent the rapid cycling on/off. On an apex is looks like this:

Defer 015:00 Then ON
Defer 005:00 Then OFF

That would set it so once the heat came on, it would be on for at LEAST 5 minutes, and once off it wouldn't turn back on for at least 15.
 
Also, I don't actually run my heat this way, though I use defer on a bunch of my outlets. I have mine set to:

Fallback OFF
If Temp < RT+-0.2 Then ON
If Temp > RT+0.2 Then OFF
If Outlet MainPump = OFF Then OFF
 
I have been using the regional temp program on my tank since the middle of last summer as well. I like that it keeps the temp pretty stable and gradually increases/decreases the temps thru out the year.
 
Is there a benefit to programming that way? Thanks

Hysteresis prevents rapid flapping on and off. Those values were probably pretty exaggerated, you might set them each to a minute or two. If your heater is small enough (wattage) to run on one if the solid state relays (1-3, 5-7 on an EB8), you can cycle that safely every few seconds... The relay is rated to millions of cycles, and the heater doesn't care. That's how sous vide (water ovens) regulate temperature so accurately.
 
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