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RO Water Controller - Purpose Next >>>


Having been fish keeping a number years FW - SW - FW and now SW again, I always find it a pain performing water changes. So my intention with this new tank is to try to make everything as automated as possible. That's where I started.

I am planning to have 2 reservoirs one for Reverse Osmosis (RO) water and one for Saltwater (SW) Mix. The RO reservoir is to used to topup the sump under the main tank. The SW Reservoir will be plumbed so that with a couple of turns of some valves (manual operation, not part of the controller). I will be able to perform the water change i.e drain the tank and then fill.

Topping up of the RO reservoir can be achieved using an 'auto shut off kit' comprising of a float valve and a pressure valve, to stop producing waste after the float valve closes. However reading the threads on, members mentioned the recording of initially high TDS readings through a RO unit on this setup. To combat this, a deionization polishing cartridge (DI) can be installed after the RO unit.. However with the frequent start stopping of this design the DI cartridge is quickly used up.

With this in mind I have designed the system so that the water in the RO reservoir is only replenished when the water level reaches the bottom float switch. The RO unit then fills the reservoir until the water level reaches the top float switch.

To combat the initial high TDS through an RO unit and to extend the life the DI cartridge. The system once activated, will initially drain the water produced from RO unit to waste prior to pushing it through the DI cartridge for a specified period..

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