I think you'd be mad to do this.
I had been DI'ing water through 2X19lt vessells for the last 5 years it got to the stage where I was using a sack of Tulsion resin every 3 weeks equating to £100 per month, and tht's with TDS of 35.
If I was you, and like you say your TDS is low, I'd RO your water with a merlin or the sort to get the water down to 0 and use that.