Started dosing trace elements now. This will be dosed for 10 days, while continuously checking nitrate (will do every other day), as this will apparently also reduce nitrates.
This is the product: Reef BluePrint Isol8:MT - Minor & Trace Elements (60 mL) - Captiv8 Aquaculture
I am estimating that the tank volume is approx 170 gallon in total (DT + sump), possibly less water. It requires one drop per 25 gallon daily, so I will be dosing 6 drops of this daily for the next 10 days.
If nitrates fall, then the dose will need to be reduced afterwards, while adding nitrates manually for the 10 days, otherwise, it can stay at this level.
After 30 days, they recommend to do an ICP which I am planning to do anyway to set a baseline.
I have used Triton in the past 12 months for ICP, but will be switching to Fauna Marin ICP going forward.