sulfer denitrifier

I feel your pain mine are 40-80 (can't really tell on the cards). I'm building a turf scrubber..that I have high hopes for. PM me for more info if interested.

 

check ammonia level of your top off water. i have nitrates out the ying yang too. just recently i tested fresh wc water and had 2.0ppm of ammonia. after doing alot of experimenting, i found out that my storage container was causing ammonia in my ro/di water. i tried different containers and got same result.
i have a 29 gallon with sump and refugium. 2 fish, 1 starfish, 2 shrimp, 1 hermit, 1 crab, 1 snail, alot of pods and mini feather dusters
i feed lightly once a week, barebottom in display with 30 lbs. lr and alot of flow.
if you think about it, i was adding ammonia everyday with top off water so naturally the nitrifacation process turns it into nitrates (always increasing nitrates). now i only top off with ro/di straight from the filter.
only time will tell, but i'm almost 100% positive my nitrates will return to normal.
i too used to do alot of wc to bring down nitrates, but in 2 days they were back the way they were

 

i use an RO/DI but i will check my topoff water. thanks for the insight.