How do you get Nitrate close to zero?

[GreenSpottedPuffer]

Don't overstock a tank, don't overfeed, weekly water changes, siphoning, good flow, good clean up crew, good LR, grow macro algae, ect. Just good all round husbandry.

Deep sand beds if done right can help but most people don't use them properly and then they can hurt the tank more than help.

Carbon dosing (vodka) can work very well but I would do lots and lots of research before you start this and know it comes with risks and the long term effects on a tank are not at all known.

Other systems like ZEOvit are great as well. Again do some research.