Great write up and very easy to follow. Will definitely help other reefers out
DIY SuperDragon ATO with safety switch (August 8th, 2008)
Summer is coming and I'm sure it will be a meltdown... so I thought I would post my homemade ATO that has save my tank when I don't have time to top it off.
Stuff you'll need is listed later towards the end of the write up.
Madison Commercial Magnetic Liquid Level Switch sensitive up from 1/8-1/4"
These units are super reliable and used by the pharmeceutical industry
Similar to this setup by www.autotopoff.com
Here you can see the Dual slosh guard so that waves or high water movement don't accidentally
trigger them to go off. They also act as snail guards to prevent a dumb snail causing a flood.
I have a 60g tank and 20g sump 1/2 full. ATO reserve is 5g.
So, in case I'm SOL and my 1st float switch fails, and my 2nd safety float fails and fills up the sump and have a poweroutage in that order I can't really overfill the sump + fuge.
Left is the 1st float switch, right 2nd float (safety), under PVC pipe there is my ATO fill tube
and to the right of that is my filthy TOM619 Filter sock
Both Slosh guards (with floats inside) are linked by velcro (safety) in between and mounted to a left over piece of acrylic (drilled with 2 holes for zip tie mounting allowing adjustability)
The acrylic is mounted to the side wall of the sump using Velcro (I don't trust hooks, hangers, etc.)
Wiring... to keep it simple it's wired to a extention cord that has a built-in switch that was cut off and rewired to the float switches, soldered and shrink tubing added (not waterproof)
The outlet is then connected to a TOM Aqualifter (no relation to TOM619) running at 3w.
Each float switch can handle 30w. The maximum a spike that can be produced by a 3W device being turned on is 10x this rating which is 30w exactly, more than this will cause the switch to fail. Therefore, a relay is not required (a eletronic switch that dosn't allow spikes). Spikes are the main cause for failure of a magnetic float switch.
The float switches are reversible so I checked them to make sure "off" is when the switch is up using a Multimeter.
-Each float switch is under $12 each at Grainger the M8000 ($25 with taxes for two)
-TOM Aqualifter pump, 3w <$10
-extension cord with built in manual switch <$10
-PVC 1.25 endcaps little bit of 1.25 PVC tubing <$3
-shrink tube, soldering iron, zip ties, velcro, acrylic (laying around)
-DIY know-how (free)
I ended up spending <$40 for my commercial setup with slosh/snail guards without a pump or relay.
If you already have some of this stuff, the float switches and ext cord $35 including a 2nd safety float.
autotopoff.com is competatively priced including a powerful relay, but with shipping it can be up to $60, but still waaaaaaaaaay more affordable than a brand name device.
I don't trust JBJ electronics, nor will I pay $$$ for a brand name complex ATO.
If I can understand the wiring the chances for disaster are pretty low.
ATTN: if your going to use a powerhead rated more than 3w your Liquid Level Switch will fail!
Potential spikes are inevitable when electronic equipment is turned on/off
Top Zip Tie is water line, below this and the unit fills FW. If the water level is ever above this line I know something is wrong (ie switch failed, or something else is wrong)
Obviously, test your new toy out in 2 containers of water before you put it to the real test.
My tank evap rate is about 1/2g per day during summer days. With a 5g reserve I won't have to fill it for at least 5-7 days.
FYI: EVERYONE SHOULD USE DRIP LOOPS WHEN DOING WIRING, FIRES AND DESTRUCTION OF A FISH TANK IS INEVITABLE AROUND WATER IF TAKEN LIGHTLY.
I ALSO RECOMMEND INSTALLING A GFCI SO YOU DON'T ELECTRO-CUTE YOURSELF.
IF YOU HAVE NEVER SPILLED A DROP OF WATER AROUND YOUR FISH TANK YOU MUST LIVE IN THE OCEAN.
Took the idea from www.autotopoff.com and made it to my liking
Melev's Reef also has a ghetto version that prob cost him $20 (but still single switch with no safety)
*Even if you only have one float switch it should not fail if the load isn't high on the pump.*
*I'm not responsible if you have problems with your unit, pump fails, wiring is done wrong, float switch fails or you nuke your tank with kalkwasser. Nothing lasts forever and neither will this float device.*
UPDATE: JUNE 5TH 2009
I'm still surprized how well this DIY works. I have never had float switch #1 fail yet and continually fill my ATO every 5 days with some Part 1 Alkalinity. I just have to adjust for Calcium once a month.
Last edited by SuperDragon; 06-05-2009 at 11:22 PM.
Thank you . I will make my this ATO.
I will be adding a relay to mine since I dont want the switch to have 110 going through it.
Last edited by theMerchant; 03-03-2016 at 11:42 AM.
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