60mV sudden drop in ORP after turning UV sterilizer on

[ReefingIsMyTherapy]

I know that most reefers would recommend ignoring ORP, and to an extent, I do ignore it, unless I see a sudden change. I just turned on my UV sterilizer, running at about 400gph on a dedicated pump, and my ORP dropped from 230mV (I know, it's a bit low already) to 170mV. I thought UV would have the opposite effect. Clean water and therefore increase ORP. Any idea what would cause the ORP drop right after I turned on the UV sterilizer?

Thanks in advance for the help!

 

[World Citizen]

I think this is nothing to worry. Orp drops from a lot of things. Probably something is getting in the water from the hardware of the UV. Some residu, oils, etc.

If the UV is killing a lot of things, that will drop ORP to, but I would find that peculiar. That would be a lot of UV killing.

Wait it out for 12 hours and look what happens.