Solid State Relay (SSR) Aquarium Heater Controller?

micaheli · Mar 25, 2020

Has anybody used an SSR for controlling an aquarium heater? I'm wondering why it's not a thing... Seems like a great way to get precise temperature control and reliability over time. My 3D Printer has a 750watt AC heated build surface and it keeps it within .02 deg C... and it's turning on and off like.... 10 times per second. Seems like that's the kind of reliability we need?

Thoughts?

theatrus · Mar 25, 2020

micaheli said:
Has anybody used an SSR for controlling an aquarium heater? I'm wondering why it's not a thing... Seems like a great way to get precise temperature control and reliability over time. My 3D Printer has a 750watt AC heated build surface and it keeps it within .02 deg C... and it's turning on and off like.... 10 times per second. Seems like that's the kind of reliability we need?

Thoughts?

As long as you bypass the internal thermostat or make sure its in the on position, there is no real problem doing this.

micaheli · Mar 25, 2020

Yeah, I was thinking of using something like this: https://www.bulkreefsupply.com/titanium-heater-element-bulk-reef-supply.html

It's element only. Plug it in and it's on. I could easily make an outlet with an arduino/etc to use a temp probe (or two) and an SSR to control it. I may try this...

Anybody else interested in the results? I'm interested in longevity/reliability while keeping the hysteresis small.

35ppt · Mar 25, 2020

I've been using SSRs for my DIY ATOs for ~3 years without failure. Only thing that ever fails is the float switch.

theatrus · Mar 25, 2020

micaheli said:
Yeah, I was thinking of using something like this: https://www.bulkreefsupply.com/titanium-heater-element-bulk-reef-supply.html

It's element only. Plug it in and it's on. I could easily make an outlet with an arduino/etc to use a temp probe (or two) and an SSR to control it. I may try this...

Anybody else interested in the results? I'm interested in longevity/reliability while keeping the hysteresis small.

Always interested. As long as the SSR does zero crossing detect there should be no issues from what I can do. Far cry better than having to hack in a Ranco if you use a good sealed element (like a stainless or titanium PRTD)

micaheli · Mar 25, 2020

35ppt said:
I've been using SSRs for my DIY ATOs for ~3 years without failure. Only thing that ever fails is the float switch.

Good to know. That's an incomparably different duty cycle load though.

35ppt · Mar 25, 2020

micaheli said:
Good to know. That's an incomparably different duty cycle load though.

No doubt.

alysak6075 · Mar 25, 2020

I keep coming back to the EB8 with the triac switches. They would be perfect for something like this.

Chuk · Mar 26, 2020

I've done it for an ATO on the aquarium its been running a little under 5 years now with no issue. As mentioned before different cycle frequency but the longevity is there.
I also built a home brew mash temp PID controller using a SSR that works fantastically. It does cycle a lot because of the PID controller maintaining +/- 0.1 deg F range but neither my heater element or the relay have had an issue yet with ~300 hrs on them over 7 years. While maintaining temp it is cycling 1-2 times a second so roughly 1,600,000 ON/OFF cycles. Not a heck of a lot of hours compared to 24/7 aquarium operation but a huge amount of cycles.

cymonous · Mar 26, 2020

I'm in the Building Automation Controls industry. I took an old Johnson Controls thermostat, connected a plastic nub remote sensor, RIB Relay RIBU1C, 24v transformer for both the t-state and RIB, 120v Outlet and power cord. I have two heaters plugged in. The 2nd heater is set for a lower temp, so its element comes on only if the 1st heater fails.

micaheli · Jun 16, 2020

@cymonous Very cool! I'm looking at using one of the INKBIRD PID controllers to control an SSR.. .I'll try it out in a bucket to start out with.

gasia · Nov 28, 2020

micaheli said:
@cymonous Very cool! I'm looking at using one of the INKBIRD PID controllers to control an SSR.. .I'll try it out in a bucket to start out with.

Did you make any progress on this? I am doing basically the same thing, and would love if you shared your results!

theatrus · Nov 28, 2020

gasia said:
Did you make any progress on this? I am doing basically the same thing, and would love if you shared your results!

Yes! And no, because time. The actual guts work fine for temperature control, but I haven’t gotten to fabbing the actual SSR board yet. Will get in that soon

gasia · Dec 8, 2020

theatrus said:
Yes! And no, because time. The actual guts work fine for temperature control, but I haven’t gotten to fabbing the actual SSR board yet. Will get in that soon

I am going to be implementing effectively the same thing in my 50 gallon reef. Would love to see a circuit diagram if you made one!