What would be the safest way to connect my reverse osmosis system directly to my sump?, the idea is to replenish the evaporated water automatically. Is there something on the market that is reliable and safe?. Thanks in advance
As above, not a good idea. TDS creep will have you burning through DI resin much more quickly and you want failsafes to avoid a flood.
I have a water station setup outside the house, near one tank that feeds that and another tank. Apex controlled. The RODI refills itself, with a TDS flush cycle, under Apex control with solenoids and optical sensors. I also use an auto shutoff valve as a backup for filling in case the inlet solenoid or upper level optical sensor fail.
I use the Apex ATK to automatically top up my stock Red Sea Reefer gravity fed ATOs (in each tank) once a day. With all the redundancy of the ATK there is no real risk of flooding the sump. I also run an optical sensor for high level sump as another safeguard, and another as a low level sensor in case the gravity fed ATO gums up.
So I never have to worry about topping up an ATO or filling an RODI reservoir manually, can leave the automation to do it's job secure that I have enough safeguards to prevent against any likely issue.