Berlin Sump Sock - NO3 source?

[Scoot]

My N03 had been declining, naturally, for a month. Last week, after several fish decided to play in the substrate, and kick up a sandstorm, I added a berlin sump sock to filter out the tiny particulates.

Within a week, my NO3 started climbing, from 3 or 4 ppm, to around 18 (guessing at the 18, it wasn't quite up to 20).

I've removed the sock, and a day later its back down to what I'd say is a 15 (midway from 10 to 20).

Feeding has been sparse - every other day. No deaths (except for a small chocolate chip star that decided to climb over my sump baffle and into a return pump and lost 3 arms - it lived a few days after that). No other changes.

All other params are normal. 0 ammonia, 0 nitrite, Ca 420, pH 8.07, sG 1.023.

Could this be the sock causing this?
I'm not due for a PWC for another week. If NO3 stays where it is, or drops, I'll hold off. If it continues to climb, I'll have to do another one soon.

Anyway - do berlin sump socks contribute to NO3 production, as other filtration media do?

 

[Innovator]

socks need to be cleaned regularly. i always have at least two on hand so they can be switched out. if the fish kicked up the sand enough and there is alot of excess crud it's getting kicked into the water column and settling within the aquarium and not just the sand. i doubt the sock caused the increase, but to be safe you can wash it and try again.