BTW, most cheap nitrate test kits are usually very innacurate...
But you can do a lot more WC, 50% weekly is what a lot do including myself. if your running only 10ppm over your tap level that isnt too bad, and I dont think 30 is going to be a serious issue but IDK, I dose nitrate in my tanks since its heavily planted, and even heavily stocked with fish I dont usually read quite that high.