Here’s a diy fail proof ATO.

[Reefs anonymous]

I made one of these many years ago and it ran for 10-15 years and had never failed. I initially used electronics I made but have since attached it to my Apex to control it. I was looking for a fail proof system and didn’t like what was available by manufacturers. Electric eyes, mechanical floats, timers, ect can all fail. But liquid mercury cannot fail. The total cost is literally pennies. Get the switch from amazon for like a $1, get wires from around the house, use an old magnet so you can attach it to the glass and adjust the height. Here’s what it looks like. The last picture is the program I use to the outlet to my pump in the reservoir to pump ro into the sump.

 

[Reefs anonymous]

I actually got the switch on eBay. It’s waterproof. I broke off the tab and stuff it into those floats and solder it to wires going to my apex.

 

[Reefs anonymous]

Adjusting the float switch. It will be placed in the sump but I’m testing it in the display.

 

[laverda]

Interesting idea. But nothing is 100% fail proof. I see 3 possible failures right off hand.
1. I doubt the wires on sensor are intended for saltwater conditions. The insulation will break down and fail over time. Salt water may get into the switch via the wires and short it out.
2. The wires will break from the constant flexing. How long it takes depends on the specific wire used.
3. Apex's can and do malfunction! I know from experience not to control critical functions solely via my apex. My apex turned my alk doser from auto to ON on 3 separate occasions emptying my dosing container, driving my alk and PH way up. It also failed by not alerting me when my PH went well past the alarm setting point.

 

[Valhalla Reefer]

I made one of these many years ago and it ran for 10-15 years and had never failed. I initially used electronics I made but have since attached it to my Apex to control it. I was looking for a fail proof system and didn’t like what was available by manufacturers. Electric eyes, mechanical floats, timers, ect can all fail. But liquid mercury cannot fail. The total cost is literally pennies. Get the switch from amazon for like a $1, get wires from around the house, use an old magnet so you can attach it to the glass and adjust the height. Here’s what it looks like. The last picture is the program I use to the outlet to my pump in the reservoir to pump ro into the sump.

Interesting.
Have you looked into Avast Marine’s ATO?
(Air Pressure Switch style)

 

[Reefs anonymous]

Interesting idea. But nothing is 100% fail proof. I see 3 possible failures right off hand.
1. I doubt the wires on sensor are intended for saltwater conditions. The insulation will break down and fail over time. Salt water may get into the switch via the wires and short it out.
2. The wires will break from the constant flexing. How long it takes depends on the specific wire used.
3. Apex's can and do malfunction! I know from experience not to control critical functions solely via my apex. My apex turned my alk doser from auto to ON on 3 separate occasions emptying my dosing container, driving my alk and PH way up. It also failed by not alerting me when my PH went well past the alarm setting point.

Ya, and a meteoroid can land on my head. Obviously these things can happen, but it’s way more fail safe than anything made and sold. Been using it for 20 years and not one hiccup.

 

[Reefs anonymous]

Interesting.
Have you looked into Avast Marine’s ATO?
(Air Pressure Switch style)

No I haven’t, this cost me like $2-3 bucks and using it for 20 or so years. If it fails then I’ll possibly look at it.

 

[NeonRabbit221B]

I love DIY projects but nothing is fail proof. Redundancy is key!

 

[Pntbll687]

I like it, and its cheap which makes it worth while to try out.

 

[Reefs anonymous]

Actually I’ve been using it about 30 years. Back then I got the mercury switch from a air condition thermostat and I used a spice bottle to float it. Today there’s eBay/amazon to get the mercury switch. I made it way back before most all these new ato were even around. If it fails I’ll report back here. That’s how confident I feel this is as reliable if not better than any on the market.

 

[laverda]

Ya, and a meteoroid can land on my head. Obviously these things can happen, but it’s way more fail safe than anything made and sold. Been using it for 20 years and not one hiccup.

Just pointing out it is not fail proof as stated. It was probably more reliable on your own electronics than the apex.

 

[lelandmarine]

Nice, reliable and cheap!