Zoas with undetectable nitrates and phosphates?

[SteveConn]

My zoas are doing ....mediocre. I've got a colony closed up
-could be irritated by spagetti worms
-I've also seen 2 sundial snails that I've pulled out and have not seen any more.

Using a webcam throughout the night on time lapse to look for more pests. Bought a butterfly fish to eat pests. Has not munched on corals yet!

Params:
Salinity @ 1.026
Ca 440
DKH 9.8
Mg 1600 (falling back into line from accidental OD)
Nitrate/ite and phosphates undetectable

For most tests I use Hanna calorimeter

I have algae in the refugium, running a phosphate reactor and an oversized skimmer for my 75g display (25g sump)

Should I disconnect the phosphate reactor and run the skimmer intermittently on a timer? I understand zoas/palys need a trace of PO4 and nitrates.

Tank is lightly stocked. SPS are coloring nicely, most LPS look good but my orange hammer could look better.Torches, Gonipora and photosynthetic gorg look good too.