I have low incoming tds, am I using too much do resin somehow?

[Biff0rz]

So I have a tds meter on the in/out of the rodi system. Incoming, after flushing, I have about 1-2 tds on the reading. Out is always 0. I filled my tank today with straight ro water to test drain & returns. It's a 230g tank w 60g sump. I've been flushing the rodi religiously whenever it stops. So I checked the di today after about 300g have been put through it. Pic attached, does that seem normal for such low tds to start with?

Ro setup is a 75gpd w the brs 150gpd upgrade used, but new. I replaced the membrane (75gpd), 3 filters, and the di (5 stage). I have a flush valve, pressure meter (reads 75 psi, no booster).

 

[Rogued_Reefer]

So I have a tds meter on the in/out of the rodi system. Incoming, after flushing, I have about 1-2 tds on the reading. Out is always 0. I filled my tank today with straight ro water to test drain & returns. It's a 230g tank w 60g sump. I've been flushing the rodi religiously whenever it stops. So I checked the di today after about 300g have been put through it. Pic attached, does that seem normal for such low tds to start with?

Ro setup is a 75gpd w the brs 150gpd upgrade used, but new. I replaced the membrane (75gpd), 3 filters, and the di (5 stage). I have a flush valve, pressure meter (reads 75 psi, no booster).

That’s pretty common when you make a lot of water. The DI resin takes out plenty of crap out of the water.

 

[laverda]

Your DI should last way longer than 300 gallons especially if you TDS going to it is zero. Typically they produce 1000 gallons or more. I suspect your source water is high in CO2. To test take some water before your DI and test the PH. Then arrate it for an hour and test the PH again. If it increases significantly you have high CO2. I used to get 2 years out of my DI making water for a 240 gallon and several other tanks, several thousands of gallons worth. After moving my DI only lasts only 500-600 gallons after I added a second DI to my system. My TDS before the DI canisters is a bit higher, but the real issue is high CO2.
There is at least one thread in the DIY forum on building a CO2 remover setup using PVC and an air pump. I really should build one myself.