Chiller, Apex, and heaters

[DLHDesign]

After several spikes of 81F+ temps that I struggled to reduce down (hot days with kids gong in/out all day long), I went ahead and added a chiller into my system. I can now keep the temps down, but I've run into another (potential) issue:

The chiller has a set point in full degrees. Setting mine to 78F (after calibrating to the Apex probe) results in the above. My heaters never run during this, so all my heat is coming from lights (I run LED's and T5's), pumps, and ambient room temperature. I could likely clean my pumps to help a little, but I did that just a few weeks back and can't imagine they are in dire need of another cleaning, so I'd like to operate from the assumption that my pumps are running normally at the moment.

The above seems like a pretty rapid swing - from ~77.8F to ~78.8F and back every ~10hrs.

Here's what I'm wondering:
The Apex can detect temp down to the tenths. This is, obviously, more accurate than the chiller's ability. I can also control the on/off power to the chiller using said Apex. So I could likely reduce that spike down to a much smaller swing, but that would cause the chiller to be switched on/off "at the wall" far more often (several times a day). Would that have a practical impact on the usable life of the chiller? I know that power-cycling refrigerators and freezers is not ideal, but I don't know if these chillers work the same way or not...

In the IDEAL world, the line would be flat (or at least have a very long wave-like pattern). My brain wants to believe that I could use the Apex and a combination of the chiller and heaters to achieve this - counter-acting the chiller with the heaters and heaters with the chiller, etc. I can't imagine that's a good system, however, as it would not only burn more power, but also would likely shorten the life of everything. Not to mention there being more likelihood of catastrophic events should one end or the other fail...

So; thoughts? What are other people doing to keep their tank's temperatures stable? And just how stable are you able to get?

 

[Selk Oner]

What kind of chiller did you buy most chillers come with a thermostat Built in

 

[DLHDesign]

What kind of chiller did you buy most chillers come with a thermostat Built in

Link is above; JBJ 1/5 HP.
Yes; it has a thermostat. The control on the chiller only allows for a set-point of a full degree - 77F, 78F, 79F, etc. The chiller seems to have a 0.8F on/ 0.2F off trigger-point that can't be configured. Eg; If the temp reads >0.8F than the current set point, turn on the chiller. When the temp reads <0.2F than the current set point, turn it off.

With the apex, I could reduce this - down to +/-0.2F, for example.

 

[Selk Oner]

I have the same chiller I set it up to my specific temperature and let it be it's turns on when I need to if you strap it up to the apex and you don't set it right it will turn on and off on and off on and off and it won't work right

The same thing is happening to you

 

[DLHDesign]

To add some details (and these are very specific to my system, of course):
It looks to average about 25-30min for my temp to go from 77.8F up to 78.2F. The chiller takes 10min to drop from 78.2 to 77.8F.
What I could do is set the chiller's control to 77F (safety stop). The chiller's plug would be configured to turn on at >=78.2F and off at <=77.8F. I imagine that there's some ramp-up time for the chiller to turn on, but this configuration would result in the chiller being on for 10min out of every 40min - or roughly 360 minutes a day.

It currently averages about 120minutes of on-time per day (two 1-hour blocks). So aside from the on/off cycling, this would triple the time the chiller is running...