Tldr: been fighting high nitrates for awhile now always been above 30ppm+ and want them to come down as coral don't look the greatest(specifically anemones). I have a 90 gallon display and a 20 gallon display both connected to a 40gal sump with a reefmat refugium and classic octo skimmer. For the life of me I can't get them to go down. I do 15% wc weekly and dose nopox very high. More explanation in the comments and some photos. Icp test from a week ago is also in pictures.
2nd part of this that isn't that important but may be linked. For my 20 gallon I have it so I have a strainer for the output for the sump. I'm guessing this is a bad design idea and maybe leading to lesser filtration than possible how would you go about fixing it to be proper? I don't want to buy a external box as they are expensive. Would putting a weir box on there fix the problem or no? Also whenever my pump stops when I turn it back on there is a chance it will not siphon.

2nd part of this that isn't that important but may be linked. For my 20 gallon I have it so I have a strainer for the output for the sump. I'm guessing this is a bad design idea and maybe leading to lesser filtration than possible how would you go about fixing it to be proper? I don't want to buy a external box as they are expensive. Would putting a weir box on there fix the problem or no? Also whenever my pump stops when I turn it back on there is a chance it will not siphon.

