How low can you go on TDS?

[DEBaker]

I was having very low hatch rates (between one and ten wigglers) until I lowered the TDS in my tank from 75 to 45 following some advice I read here at Simply. My hatch rate went way up, only 12 eggs died. Is there a minimum TDS that should be maintained before it could adversely affect the health of the discus or the fry?

Any advice would be appreciated.
Thanks,
Don