Protein Skimmer Removing Trace Element Additive (I think)

[Exus]

So I'm pretty sure the trace elements I recently started dosing weekly is getting skimmed out by my protein skimmer. The skimmate the day after dosing is greenish-blue, and the Kent Trace Elements additive I dosed is blue. I turn the skimmer off for about 2 hours after dosing, and it still seems to get skimmed out. How should I interpret this? Should I keep dosing even though some of it gets quickly skimmed out?

I started dosing because I've started carbon dosing my 150g tank, 3rd month now since last water change. Maintaining a stable 5ppm Nitrate and 0.04 Phosphate.

 

[blaxsun]

Where are you dosing in your sump?