My goal for building a diy auto water changer was to help keep my tank alive while on a long vacation with my reefkeeper controller and not upgrading to an apex. Info on this was fairly tough to find so I wanted to share in case anyone else was thinking of doing something like this.
I found a couple of extra power bars online for my RKL and bought a Tunze 3155 ato and a brs 50 ml per minute dosing pump. I added the dosing pump to outlet 4, my Tunze 3155 ato in outlet 2 with the pump placed in clean saltwater and another ato in outlet 3 with the pump in RO water. I set channel 2 and 4 to turn on for a couple of hours while channel 3 turns off for the exact same time. The dosing pump removes water from the tank and drains to an empty bucket. Clean saltwater is added back in to the tank by the Tunze at a gradual pace. My ato in fresh water turns off to make sure my salinity stays accurate. The dosing pump is an easy way to gradually pump water out while not back siphoning when off. I think I might eventually add a salinity probe for some redundancy and possibly a float switch in the clean saltwater to ensure the system turns off if my saltwater runs too low.
FYI, I have a small tank so 2 and a half hours works for me. If I had a bigger tank I think I would increase how many days a weak I would have this operate. Currently I run this at night because the pump is fairly loud and I want to test this before I leave for a vacation.
I found a couple of extra power bars online for my RKL and bought a Tunze 3155 ato and a brs 50 ml per minute dosing pump. I added the dosing pump to outlet 4, my Tunze 3155 ato in outlet 2 with the pump placed in clean saltwater and another ato in outlet 3 with the pump in RO water. I set channel 2 and 4 to turn on for a couple of hours while channel 3 turns off for the exact same time. The dosing pump removes water from the tank and drains to an empty bucket. Clean saltwater is added back in to the tank by the Tunze at a gradual pace. My ato in fresh water turns off to make sure my salinity stays accurate. The dosing pump is an easy way to gradually pump water out while not back siphoning when off. I think I might eventually add a salinity probe for some redundancy and possibly a float switch in the clean saltwater to ensure the system turns off if my saltwater runs too low.
FYI, I have a small tank so 2 and a half hours works for me. If I had a bigger tank I think I would increase how many days a weak I would have this operate. Currently I run this at night because the pump is fairly loud and I want to test this before I leave for a vacation.
