My reef has gone as high as 40s-50s for months at a time in the early stages when i didn't have a good grasp of what i was doing. Not that it was a good thing but i didn't suffer any loses in coral or livestock. I didn't have any sps
but i had a lot of LPS
and nothing happened. That said, I wouldn't make it a practice of running high nitrates but It's not the end of the world to have 20ppm. I keep mine in the 4ish ppm
using the red sea kit. Switching out to a simpler refugium with filter socks that take 2 minutes to change vs. my wet/dry that i was rinsing filter media has kept me on time rather than being lazy and letting it go for another day. If it seems less like work you're more likely to do it lol. Maybe try a little "wetter" skim. It will fill faster but also pull out some more waste hopefully.
EDIT: BTW i have been in this now for almost 5 years so im no expert but I've learned A LOT more now than I did back the lol.