Apex program for heater

Thalia · Feb 20, 2026

Hi, can someone tell me if this programming will keep my tank between 75 and 78? Letting the temp get a little cooler over night and warmer during the day?

Fallback OFF
Set OFF
If Tmp < 75.0 Then ON
If Time 12:00 to 8:00 Then ON
If Tmp > 76 Then OFF
If Time 16:00 to 12:00 Then ON
If Tmp > 77 then OFF
If Time 8:00 to 16:00 Then ON
If Tmp > 78 then OFF

lapin · Feb 20, 2026

If your tank gets hot during the day without the heater being on then the programming to turn off the heater will not matter much

Thalia · Feb 20, 2026

lapin said:
If your tank gets hot during the day without the heater being on then the programming to turn off the heater will not matter much

No, the tank doesn't get hot without the heater on. The purpose of this program is to let the tank be cooler in the evening/night and warmer during the day.

Bartanto · Feb 20, 2026

Why let it get so cool? I’d try to keep it at 78! I get antsy in the pantsy if more than, say a .7° degree swing in 24 hrs. What size tank? If you’ve got an Apex, adding a temp probe controlled fan is easy peasy. They work great.

Thalia · Feb 20, 2026

I thought having a bit of a swing over the course of a day was more natural, the ocean doesn't stay the same temperature day to night. I didn't think 3 degrees was too dramatic but I could tighten it up some...

It's a 75 gallon tank. It doesn't seem to be overheating, but it's not summer yet so I'll keep the fan in mind, thanks!

Bartanto · Feb 20, 2026

Thalia said:
I thought having a bit of a swing over the course of a day was more natural, the ocean doesn't stay the same temperature day to night. I didn't think 3 degrees was too dramatic but I could tighten it up some...

It's a 75 gallon tank. It doesn't seem to be overheating, but it's not summer yet so I'll keep the fan in mind, thanks!

Ah. Well, it’s best case it’s not too hot. Others with more experience will be better resource on the swing but if I’m voting I’d keep temp as exactly close to 78 as you can.