Filtration / ULNS

I’m trying to decide which route to go down for removing or exporting Nitrate in my 5 x 2 x 2 mixed coral tank. The tank has been running for several months now and I change 10 gallons weekly. I run a Bubble Magus Curve 9 protein skimmer 24/7 and grow cheato in my sump. The lighting is 6 x 54 watt T5 with a mixture of D&D Guiesman tubes. I have rather a lot of softies and LPS (sun corals, duncan’s, candy canes etc) which I must admit to, I do feed rather heavily, there is also a growing...