That is what I would do too. Just do the water and stick with the hob for now.
you will also need clean water for topping off the tank every day, so the rodi is a good investment.
You will get about 100-200 gallons (maybe more) out of the DI resin, then you replace that. The resin can be bought in a bag and you refill it yourself or you can buy a replacement prefilled cartridge. You change it when it changes from blue to brown. Here is a link to the prefilled cartridge:
Aquatic Life DI Color Changing Mixed Bed Resin Cartridge
To drain the tank, you can just run a hose to a drain and suck on it to start a siphon. Or get a little pump And tubing:
SICCE MICRAPLUS Compact Aquarium Pump, 158 GPH, for submerged use in freshwater and saltwater
Ok thanks for that. So with the unit that I linked at that cartrige it will give 100-200g every day? Even though it says 50g?