Hi Guys
I need some advice on my scrubber, every week a get GHA and a good amount off of my screen but i cant seem to bring my nitrates down to 0 or any where near, they are about 10 to 15 ppm. and phosphate is always 0 or as close as i can see it to be (salifert)

i only feed 1/2 a cube a day and it all gets consumed within 5 min,

its 130 x 150 cm lit only on 1 side with a 10w led 8 red 1 blue

i run it on a 14 hour photo period and it get about 3000 gph flow,

Top up is done with RO.

visually it performs flawlessly the stuff i pull from the screen i have to do it every 7 days its so thick

thanks in advance