I have a 75g tank with a 20g long sump. I set the sump up last weekend but tank has been running for 5 months now. Issue I'm having is I'm burning through RO water. I have a 10g ato tank and before the sump that would last me almost 2 weeks. The sump started running on Monday and by today I'm down to about 4 gal left in the RO tank. I have checked my sensors for the ato and they are working properly. Also have adjusted the gate valve and the return pump controller but it's like I can't find that balance. The water level in the return chamber keeps fluctuating causing the ato to keep cycling in fresh water. The constant cycling is causing the water level to rise in the MD where it is almost covering the baffle inlets for the overflow box. Other reason I think it's adding way too much RO is because my salinity is dropping. My setup is a eshopps pf-1200 using the herbie method. One drain to sump with a gate valve. The return pump is a 800gph DC controllable pump.