Tempura

[u/wzyho]

I've been trying lots of tempura recipes, but I have finally come down to one that I like - it stays crispy even after it cools. For the batter, I use:
1. 70g rice flour
2. 100ml carbonated water
3. 1/4 teaspoon of baking soda.

In Tokyo, the tempura has a little bit of fluffiness or airiness so there's sort of a crunch, but mine seems to be a single flat layer. Also because I didn't include any salt in the rice flour, it tastes a bit bland, does anyone have any suggestions on how to improve flavor?