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Q11068 - HOWTO: How to Set-up an Auto Top-Off System By Daniel Somboonsiri, Reef Squad

For most aquarium hobbyists, the aquarium is a source of relaxation: a way to escape and unwind after a hard day. We look to the subtle sounds, the gentle sway of current and the graceful movement of fish to bring the beauty of underwater worlds into our homes and offices. Some maintenance will always be involved with keeping aquaria, but the less we have to work to enjoy our aquariums the better.

Enter automation.

Maintaining an aquarium is beginning to look a lot more Jetsons than Flintstones. Today, aquariums can be almost fully automated, even monitored and maintained by mobile phone. While we're not going to go into every possible automated device today, I would like to cover one that can make your aquarist life a whole lot easier while creating a healthier environment for your fishy friends.

I don't know about you but I hate lugging buckets and jugs of water around.

No matter how hard I try, water spills on the carpet, the dog drinks from the bucket when my back's turned and my wife is inevitably upset. This is where an auto top-off comes in: a top-off system will sense when your water level drops and replenish the water automatically. No more constantly lugging water or worrying about someone coming by to fill up the tank while you're away.

Auto Top-off System
Personal sanity and carpet cleaning bills aside, an automatic top-off system will make for a healthy tank. Saltwater systems will maintain a constant salinity. Protein skimmers will function more steadily. Filter systems will not turn into waterfalls get louder as the water level drops. This isn't just for your sanity; it's for your fish as well.

There are plenty of great auto top-offs on the market with different selling points. In choosing one, I recommend looking for something that fits in your application and has good backup features. There's no point to an automated top-off system if the sensors fail, flooding the tank. Most top-offs on the market will have some form of backup to prevent that from happening.

There are two basic ways of setting up a top-off system: fully and partially automated.

In a partially automated system, water goes from a freshwater reservoir (which is periodically refilled) into your system. The other method is to fully automate your system so that water goes all the way from the tap, through the purifier and the reservoir to the system.

Both have their benefits.

Should the sensors and backups fail in a partially automated system, damage is limited to the water in the reservoir. In a fully automated system, there is a slightly greater risk of flooding… but little maintenance required. Hopefully I haven't discouraged you away from setting up your own auto top-off because a well designed system is reliable and will make your life a whole lot easier.

A side note about fully automated systems: connecting your reverse osmosis system directly to your tank may seem like a great idea, but there are a few reasons it is not. If the float fails, water is going into your tank until someone notices. Apply Murphy's law and this scenario is bound to happen the day after you leave for vacation. In addition, RO systems are not designed to produce small quantities of water. If only a cupful or so is used at a time it will allow a lot of impurities through. This will either pollute your tank or expend your DI cartridge in short order.

Let's get down to the installation.

For this article, we will be using a JBJ Automatic Top-Off (ATO) System. I like the JBJ ATO because it includes two float switches and a handy internal feature that shuts off the pump if it's been on too long. If you haven't already noticed, redundancy is key here.

Here is a list of parts we will be using: In the fully automated setup (assuming you already own an RO/DI), you'll also need:
JBJ Automatic Top-Off (ATO) System
Auto Top-off System Sensors First, take all your supplies out of their respective boxes to make sure you have everything you need. Before installing the ATO unit, power it up and test the sensors to see how they work. It's much easier to do this before you're awkwardly positioned under your aquarium. When the sensor trips, the sensor light should light on the head unit. If the sensor tells the head unit that the water level has dropped, the pump light will go on, signaling that power is being sent to it.

The two sensors on the ATO operate by floating in water. They trip when the float goes up or down depending on how they are put in. My preferred method, not listed in the manual, is to set up the first sensor (on the left in the picture) to tell the ATO when the water level drops too low in the sump. Normally, the second sensor would go in the freshwater reservoir to keep the pump from running dry. We don't need to worry about that with the Tom Aquatics Aqua-Lifter. Instead, we're going to install it in the sump just above the water line. This will shut off the pump in the rare case the first float gets stuck.

Once you've tested the floats with your hands to make sure they are installed correctly you can move onto the pump. Plug the Aqua-Lifter into the outlet on the ATO. Run tubing from the reservoir to the “in” on the pump then a length of tubing from the “out” on the pump to the sump. Be sure not to put the tubing underwater in the sump. It is possible to create a back siphon and accidentally empty the sump back into the reservoir which we definitely do not want. Use the MagClip to secure the tubing above the waterline.

Fill up the reservoir and it's ready to go. Here, I've used a 5 gallon jug with a hole drilled in the cap for the tubing. In my system, I hide the reservoir inside a large wicker basket beside the stand to make the area look nicer.

Next, we'll explain how to install a fully automated top-off system. This setup will require the float valve kit. This keeps the reservoir full to provide a continuous supply of water. The main components are the shut off valve and the float. The float stops water from flowing into the reservoir once it is full. The shut off valve stops water from flowing through the RO system once the reservoir is full. Otherwise water would continuously run through the system, depleting the filters and running up an expensive water bill. We'll go over the setup quickly here. Refer to the installation instructions for complete details.

Aqua-Lifter Pump
Auto Top-off System Reservoir First, let's setup the shut off valve. The valve will screw into the inlet on your reverse osmosis membrane. The inlet tube will go from your carbon pre-filter into the valve. Replace the elbow fitting coming out of your membrane's product line with the included check valve. Next, cut the tubing on the product (purified) water line coming out of the membrane. This is the tube that goes from the membrane to the DI cartridge. Insert a Tee in the line and replace the cut tubing. Run tubing from the Tee back into the solenoid. When pressure builds up in the system because the float valve is closed it will trigger the shut off valve to stop allowing water through the RO system.

On to the reservoir. Drill a hole through the side wall of the reservoir (a trash can, for instance). Insert the float valve into the hole. Run tubing from the outlet of the DI into the float valve. This completes the installation of the shut off kit.

To complete the installation of the fully automated system, you'll need to set up the pump. Run tubing from the reservoir into the inlet of the pump and from the outlet of the pump to the reservoir. Again, be sure not to submerge the tubing in the sump.

Congratulations! You now have your very own auto top-off system. Your carpets, arms and fish will thank you.

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Approved Comments...
very informative Approved: 3/3/2014
great article. Approved: 3/4/2011
Photos do not appear in my Safari browser, reducing the effectiveness of the article. Approved: 12/31/2010
Though I understand how to set it up some more pictures or a diagram of the entire setup would be great. Should have mentioned a little more on partial auto top-offs. Mine has a 4 gallon reservoir, accurate to 1-2 millimeter change in water level, requires no power or complicated sensors, and cost about $10. Oh, and its not possible to have it over flow the sump. I still have to carry a bucket of water to refill the reservoir but only once every 3-4 days, depends on the size of the reservoir/evaporation. I can leave for a weekend with no worrys at all. Approved: 11/6/2010
Nice article - might wanted to add an additional paragraph talking about some of the advanced features - for example I had an issue because of a large sump and the small pump used the device would shut-off before the sensor triped - turns out the device stops after 3 min 45 sec but can be configured to go up to 14 min before shutting down Approved: 7/18/2010
Wow, solved my vacay plans! Im a single 50 year old woman and followed the instructions and put this together in a flash. I was losing about 2 gallons from evap. and didnt know what I was going to do on Vacay for 4 days. This process and products have set me free! thanks for the great article! Approved: 6/13/2010
not enough pics.... Approved: 6/12/2010
too much bla bla bla in the beginning (I dont need a personal story) then not enough pictures. Approved: 6/8/2010
Very informative Approved: 6/7/2010
I have been looking into installing a top off system and this article really provided the information I needed to know. Approved: 6/7/2010
Well written and complete. Approved: 6/6/2010
Good article, although: (1) it assumes that no saltwater is lost due to skimming or other processes. I intentionally skim quite wet, and so for topoff I use about a 50-50 solution of RO/DI and saltwater. I have to adjust the ratio depending upon seasonal evaporation rates. (2) With your reservoir connected to your RO system, you are still asking it to make a few ounces of water at a time. Id suggest using a manual valve as well as the reservoir float valve to provide manual turn-on and auto shutoff. Not quite fully automated, but pretty close. Approved: 6/6/2010
Well balanced Pros & Cons,Redundancy is Very Recommended from personal experiences "sooner or later something WILL malfunction" Guaranteed. Approved: 6/6/2010
very helpful Approved: 6/5/2010
I love the idea that enjoying my system now! has become a lot easer than working for it. hats off to you guys. thefishman8508 Approved: 6/5/2010
i was wondering about using an auto-top-off pump and this article helped Approved: 6/5/2010
seems to me that all the bases were covered, pros and cons; and especialy having a fail safe system. Approved: 6/5/2010
Didnt demo the Level-Loc ATO! Approved: 6/4/2010
Article Details
Created on 6/2/2010.
Last Modified on 8/7/2012.
Last Modified by Dot Yuson.
Article has been viewed 35716 times.
Rated 2 out of 10 based on 370 votes.
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