So far switching to heater control with reef-pi as a fail safe my fluctuation in temp is +/- .5. (between 78 and 78.5) I have not put my Aqueon online yet so thats using the ehiem bi-metal heater. I can say when I had reef-pi doing the control, checking every minute, my temp was always within .1 degree of my target. I kind of like that stability and would much rather have reef-pi do the control. I may however change my mind once the solid state Aqueon is my primary heater.
In the meantime I am re designing my power strip. I am thinking to do a mix of solid state and mechanical relays. For the heater relay I think instead of going with a Chinese ebay-special high current solid state relay I am going to go with this Panasonic zero cross 15 amp relay
https://www.arrow.com/en/products/aqa211vl/panasonic
- My ATO uses a toms aqualifter pump which does not like SSR's so it will be a mechanical relay
- Return I want to run normally closed so that will be a mechanical relay
- Wavemakers turn on and off every hour so I will use solid state
- Skimmer, scrubber, and sump light rarley switch so I could use mechanical or SS.
So I am looking at probably doing 4 solid state relays and 4 mechanical.