I'd still do a water change on a regular basis, I do 25% a week. My nitrates show about what yours does right before a water change. It goes down, and slowly creeps back up through the week. I've found that with my water supply here in Eau Claire, a big water change effects almost all my plants in a bad way. I have a high pH from the tap, which the tank lowers. I top the tank off due to evaporation with distilled water once and a while. You want to strive for stability, wild swings in anything is bad.
Depending on a lot of things, like what you use for water, plant density, stocking, fertilizers, light levels, oxygen levels, CO2 levels, and the boogeyman in your tank, you will have to change things slowly and observe what happens. Keep reading everything having to do with any problems that occur, and then read some more.
I'm glad you like your julii's, they should be very happy in your tank. They don't get very big, and they will keep things tidy. Just don't overfeed, that might be the hardest part of keeping a tank. The fish always seem hungry, but they are gluttons.
Good luck, pretty soon you can fill in your middle and top levels of your tank with fishies.
Wouldn't you like to beside the seaside?