DIY ATO

[bfessler]

Here is an enexpensive ATO that can be adapted to most any size tank. I have been working on a simple gravity fed ATO that has no moving parts and will supply sufficient water to the display to allow me to vacation and go on business trips without having to worry about the water level in my tank. The following design fits that purpose. Here are a couple of my prototypes and then the finish product with instructions.

My first attempt utilized a rubbermaid canister. Unfortunately the rubbermaid seal is not air tight under the suction created by the ATO.

My second attempt utilized a sports water bottle and actually worked but the volume at 64oz was insufficient.

I found this container at Cal Ranch Stores and it fits the bill perfectly. It has 2 nubs to connect the tubing to and comes in sizes from 1 gallon to 7 gallons.

This is a simple project and takes between 10 and 30 minutes to set it up. Here are the instructions.
1. Gather the supplies. You will need the following
Little Giant Poultry and Game Bird Waterer - Available at Cal Ranch Stores.
1' of 3/4" ID Tubing
2 - 3/4" Barb by 1/2" FPT Elbow Fittings
2 - Hose Clamps
1 - 1/2" FPT by 1/4" Barb Fitting
1 - 1/2" Close Nipple
1 - 1/2" Ball Valve (Threaded)
1 - 1/2" MPT by 1/4" OD John Guest Fitting
1/4" OD Tubing
1/4" ID Tubing
Small Zip ties
Teflon Thread Tape
Silicone Plumbers Grease
2. Take the distribution tray and the small black cap off the waterer and discard
3. Drill a hole in the top outlet barb. This is for venting the unit.
3. Cut 2 - 2" pieces of 3/4" Tubing and fit one end on hte 3/4" Barb fitting and the other to the water outlet barbs on the waterer. Use a hose clamp to secure the tubing to the Waterer.
4. Put thread tape on the 1/4" Barb x 1/2" MPT fitting and attach to the Top 3/4" Barb x 1/2" FPT Elbow Fitting.
5. Put thread tape on the 1/2" nipple and attach it to the bottom 3/4" Barb x 1/2" FPT Elbow Fitting and the 1/2" Threaded Ball Valve.
6. Put thread tape on the John Guest Fitting and attach to the Ball Valve.
7. Attach the 1/4" OD Tubing to the top Barb Fitting.
8. Attach the 1/4" ID Tubing to the John Guest Fitting Note: Apply a little Silicone Grease to the tube before inserting into the John Guest Fitting.
Note: I found that it is necessary to use a larger diameter tubing on the top/Air Vent tube than the lower/water supply tube to induce flow.
9. Zip tie the 2 tubes together about every 6" This helps keep the tubes form tangeling.
10. Run tubing to Tank and position them at desired water level.
11. Cut off excess tubing.
Note. I found it works best if you cut the Water Supply tube about 1/2" Longer than the vent tube.
12 Secure the cut tubing in position If there is something you can put a zip tie around you can simply zip tie the tubing in position or use a suction cup or other method to secure the tubing. Tubing should be positioned at the water level you are trying to maintain. (Edited for clarity)
13. Apply Silicone Grease to the O ring for the screw on top. This will assure an air tight seal and make attaching the top easier

 

[Anonymous]

I can't see your pictures here at work so will review them at home if I get the time.

I would recommend you try some kind of drip system adjusted to your evaporation rate. You should be able to adjust it to keep the system going for days/weeks while you are away.

One thing on atos is that they by design add water when the sump level is down. The problem is that the sump level can be down from evaporation or because an overflow has failed. In both cases the ato adds water to the system. But in the later case the upper container water level rises until it floods or the ato runs out of water. In order to avoid that you have to kill the ato or the return pump when the upper container levels' is above a certain level.

Just to keep things simple, I would recommend a drip system.

Actually what I did recently and not recommended, is I just killed the return pumps for the 5 days I was gone. For shorter times I "superfill" the sumps. :lol:


my .02

 

[Anonymous]

Actually, his design is based on water level and its ability to hold the air pressure. It is not obvious in his description as to where the vent tube goes (I read it quickly), and it is critical element to make this work. The container need to be air tight, sufficiently strong (a plastic bag won't work), and the vent tube need to be positioned right at the water line where you want to keep the level at.

When water level goes below the vent tub opening, air will get sucked in as gravity pull the water down. As the water level goes up due to the top off water, the vent opening will be sealed, and eventually the air pressure will prevent additional top off water from going into the tank. Nurce or something spelled similar, was a commerical designed based on the same principle, and it has been around in the hobby for decades.

 

[bfessler]

I can't see your pictures here at work so will review them at home if I get the time.

I would recommend you try some kind of drip system adjusted to your evaporation rate. You should be able to adjust it to keep the system going for days/weeks while you are away.

One thing on atos is that they by design add water when the sump level is down. The problem is that the sump level can be down from evaporation or because an overflow has failed. In both cases the ato adds water to the system. But in the later case the upper container water level rises until it floods or the ato runs out of water. In order to avoid that you have to kill the ato or the return pump when the upper container levels' is above a certain level.

In this case the water line is measured inside the overflow and there is no sump to worry about. Because the system works like a sparkletts bottle adding water when the water level dips below the vent line and the container is air tight no water can overflow the tank unless there is a break in the tubing or the canister.

This particular ATO is feeding a 10G aquarium so evaporation affects water quality fairly quickly. I have also just built a 7 Gallon unit that is feeding my 55G Frag Tank which also is sump less.

Actually, his design is based on water level and its ability to hold the air pressure. It is not obvious in his description as to where the vent tube goes (I read it quickly), and it is critical element to make this work. The container need to be air tight, sufficiently strong (a plastic bag won't work), and the vent tube need to be positioned right at the water line where you want to keep the level at.

When water level goes below the vent tub opening, air will get sucked in as gravity pull the water down. As the water level goes up due to the top off water, the vent opening will be sealed, and eventually the air pressure will prevent additional top off water from going into the tank. Nurce or something spelled similar, was a commerical designed based on the same principle, and it has been around in the hobby for decades.

Another old school idea that still works today. Your right on all points. The location of the Vent tube is written in the instructions for the build. From the first attempt description I pointed out the need for an air tight canister, The Rubbermaid seal was not air tight under the suction created by the weight of the water.
You can see from both the first and second attempts the supply and vent lines and where they go. Because I located the ATO slightly away from the display and positioning can be seen in the other photos, I didn't include a photo of the placement of the final product.

 

[bfessler]

One of the benefits of this system is that it is not dependent on electricity or mechanical float switches to maintain the water level. If properly installed it will not overflow a tank or sump, with the exception of a clogged overflow to the sump which would likely overflow the display regardless of the method used. An added benefit in case of a flood is that the amount of water that will overflow the tank is limited to the amount of water left in the ATO canister. When a float valve connected to an RO unit fails water will continue to flow until it is shut off which can dilute salinity levels to the point of disaster.