I set up a Red Sea Reefer 525 a little over a year ago and decided from the start that I was going to use the included ATO reservoir as a small refugium. The right side of the cabinet is completely full of dosing containers, power supplies, and Apex components so I did not have room for an ATO container. I travel for work so I wanted something to top off the tank that wouldn't need to be refilled every few days or even every week so I decided to go with the ominous never ending top off system by connecting my RODI directly to my aquarium. I am by no means an ATO pioneer and I am certainly not the first person to do this but I haven't seen any full single write-up about this setup or how to deal with the challenges yet. I know a lot of people would discourage this, but after a year without a single problem, I figured I'd share my setup.
Setup:
I use a 150 GPD 6 stage BRS RODI system with the output line (passed through the wall) connected directly to my display tank sump float valve. It is also connected to my AIO frag/quarantine tank which is in a separate room. The system is run by one Neptune ATK in the DT sump and one in the QT. Instead of opening and closing a manual valve, or using a pump in an ATO container, each tank uses 2 Neptune solenoid valves on the RODI product water line connected in series for redundancy. The display tank is set to top off for no more than 5 minutes and no more often than every 3 hours (I'll explain why in a moment). The tank has 3 separate leak detectors under the stand which when triggered will shut off all of the solenoid valves as well as a master solenoid valve on the RODI supply line. The quarantine tank only has 1 leak detector.
TDS creep:
One of the problems with a setup like this is that when the system first turns on, the water initially coming out of the RO membrane has drastically higher TDS. My area has relatively high TDS water already at about 250 ppm going into the RODI system. For about 45 seconds, the TDS coming out of the RO membrane can be as high as 100 ppm then slowly decreases to its "running value" of about 6-8 ppm. This can deplete my DI resin very quickly, especially if the system is cycling on and off frequently (as it does in an ATO system).
To deal with this, I have installed a "DI bypass valve." When the system first turns on to top off either tank, the bypass valve opens and flushes the high TDS water down the drain. After about 45 seconds, the bypass valve closes and the ATO solenoids open. At this point the water going through the DI resin is down to 6-8 TDS. The system tops off about 1-3 gallons per day in the display tank depending on the temperature and each canister of DI resin now lasts me about 3.5-4 months. Since the system does flush all of the water down the drain for 45 seconds, I've limited it to topping off every 3 hours to save some water.
Risk management:
1. Dual solenoid valves are installed in series so if one fails open, the other one will stop the flow of water.
2. One master solenoid to shut off the entire RODI system in the event of a leak/overflow.
3. Each solenoid is individually tested each month to verify that it is not sticking open or closed (this takes me about 20 seconds). The float valve is also tested monthly.
4. I have a virtual outlet programmed so if the tank is in need of a top off and either valve does not open and top off the system, I will receive a notification.
5. I have a total of 4 leak detectors; 3 on the DT and 1 on the QT that will shut off the solenoids if a leak is detected.
6. The display tank RODI line has a 1/4" flow sensor that graphs the actual flow of water so I can see how often the system is topping off.
7. I removed the float valve from the ATK magnetic mount and moved it to the original mount included in the Reefer sump. This way, if the magnet ever gets pulled off, the system will not be able to top off above the fixed float valve.
8. The RODI lines themselves are wall mounted inside a cord cover so I don't have to worry about my dogs chewing the lines or the lines getting kicked.
9. ATK optical sensors are gently cleaned periodically.
I had the valves programmed to shut off if the conductivity probe measured a substantial drop but my Neptune conductivity probe only lasted about 6-8 months and it was quite erratic when it was still "working."
Future plans/upgrades:
1. A webcam would be a nice way to see what is happening when I am not around but placing the camera would be difficult.
2. I would also like to install a solenoid valve to automatically flush the RO membrane, but I have run out of 24vdc ports. Since I do have so many solenoid valves, I wish that Neptune Systems would offer a 24vdc module with 4 or 5 of just the 24vdc ports since each EB832 only has 2. Some other modules have a single 24vdc port (like the FMM) but I have still used them all. They do have a 24vdc power supply that can open and close the valves using an outlet on the EB832, but I have also run out of outlets.
3. While I would like to install a Flow-Lok leak detector as a primitive backup, I do not have anywhere that the RODI line sits on the floor so I do not think this would work but I will think more about this option as well. One thing I don't like about this is in the event that the sensor was triggered by an ATO-unrelated accident (spilling a bucket or a glass) the Flow-Lok would shut off the line and I would have to be home to fix it.
4. I plan to purchase a spare optical sensors or 2 for the ATK since these sensors have been known to fail.
5. I would like to add a 1/4" flow sensor to the RODI input line so I can monitor the total water flow through the RODI system in case of a DI bypass valve failure.
The system has now been set up for about 14 months and I have not had a single leak or overflow that I did not cause (I now have safeguards for filling 5 gallon buckets too). While this setup does have risks, a conventional ATO system has its own set of risks and I feel that I have enough safeguards in place to reduce the risk to a reasonably level. While the cost to implement the system was fairly high compared to a conventional ATO, the system has been virtually maintenance free for the last year and I have not lost a moment's sleep worrying about a flood.
Setup:
I use a 150 GPD 6 stage BRS RODI system with the output line (passed through the wall) connected directly to my display tank sump float valve. It is also connected to my AIO frag/quarantine tank which is in a separate room. The system is run by one Neptune ATK in the DT sump and one in the QT. Instead of opening and closing a manual valve, or using a pump in an ATO container, each tank uses 2 Neptune solenoid valves on the RODI product water line connected in series for redundancy. The display tank is set to top off for no more than 5 minutes and no more often than every 3 hours (I'll explain why in a moment). The tank has 3 separate leak detectors under the stand which when triggered will shut off all of the solenoid valves as well as a master solenoid valve on the RODI supply line. The quarantine tank only has 1 leak detector.
TDS creep:
One of the problems with a setup like this is that when the system first turns on, the water initially coming out of the RO membrane has drastically higher TDS. My area has relatively high TDS water already at about 250 ppm going into the RODI system. For about 45 seconds, the TDS coming out of the RO membrane can be as high as 100 ppm then slowly decreases to its "running value" of about 6-8 ppm. This can deplete my DI resin very quickly, especially if the system is cycling on and off frequently (as it does in an ATO system).
To deal with this, I have installed a "DI bypass valve." When the system first turns on to top off either tank, the bypass valve opens and flushes the high TDS water down the drain. After about 45 seconds, the bypass valve closes and the ATO solenoids open. At this point the water going through the DI resin is down to 6-8 TDS. The system tops off about 1-3 gallons per day in the display tank depending on the temperature and each canister of DI resin now lasts me about 3.5-4 months. Since the system does flush all of the water down the drain for 45 seconds, I've limited it to topping off every 3 hours to save some water.
Risk management:
1. Dual solenoid valves are installed in series so if one fails open, the other one will stop the flow of water.
2. One master solenoid to shut off the entire RODI system in the event of a leak/overflow.
3. Each solenoid is individually tested each month to verify that it is not sticking open or closed (this takes me about 20 seconds). The float valve is also tested monthly.
4. I have a virtual outlet programmed so if the tank is in need of a top off and either valve does not open and top off the system, I will receive a notification.
5. I have a total of 4 leak detectors; 3 on the DT and 1 on the QT that will shut off the solenoids if a leak is detected.
6. The display tank RODI line has a 1/4" flow sensor that graphs the actual flow of water so I can see how often the system is topping off.
7. I removed the float valve from the ATK magnetic mount and moved it to the original mount included in the Reefer sump. This way, if the magnet ever gets pulled off, the system will not be able to top off above the fixed float valve.
8. The RODI lines themselves are wall mounted inside a cord cover so I don't have to worry about my dogs chewing the lines or the lines getting kicked.
9. ATK optical sensors are gently cleaned periodically.
I had the valves programmed to shut off if the conductivity probe measured a substantial drop but my Neptune conductivity probe only lasted about 6-8 months and it was quite erratic when it was still "working."
Future plans/upgrades:
1. A webcam would be a nice way to see what is happening when I am not around but placing the camera would be difficult.
2. I would also like to install a solenoid valve to automatically flush the RO membrane, but I have run out of 24vdc ports. Since I do have so many solenoid valves, I wish that Neptune Systems would offer a 24vdc module with 4 or 5 of just the 24vdc ports since each EB832 only has 2. Some other modules have a single 24vdc port (like the FMM) but I have still used them all. They do have a 24vdc power supply that can open and close the valves using an outlet on the EB832, but I have also run out of outlets.
3. While I would like to install a Flow-Lok leak detector as a primitive backup, I do not have anywhere that the RODI line sits on the floor so I do not think this would work but I will think more about this option as well. One thing I don't like about this is in the event that the sensor was triggered by an ATO-unrelated accident (spilling a bucket or a glass) the Flow-Lok would shut off the line and I would have to be home to fix it.
4. I plan to purchase a spare optical sensors or 2 for the ATK since these sensors have been known to fail.
5. I would like to add a 1/4" flow sensor to the RODI input line so I can monitor the total water flow through the RODI system in case of a DI bypass valve failure.
The system has now been set up for about 14 months and I have not had a single leak or overflow that I did not cause (I now have safeguards for filling 5 gallon buckets too). While this setup does have risks, a conventional ATO system has its own set of risks and I feel that I have enough safeguards in place to reduce the risk to a reasonably level. While the cost to implement the system was fairly high compared to a conventional ATO, the system has been virtually maintenance free for the last year and I have not lost a moment's sleep worrying about a flood.
