This looks like 40 ppm so if I did 50 WC I think it will knock it down alotttIf you do a 50% WC your nitrates will be at 40 ppm to 80 ppm, so that’s still too much.
I’m new at saltwater so I don’t know what the best solution is. If it was freshwater, I would do as close to 100% WC as possible.
Let’s wait for an experienced hobbyist.