Can phyto crash ORP?

Mr.BobDobalina · 2026-10-31T13:21:37-0400

Just started dosing some phyto the past 3 days and ORP has sunk like a stone from 415 to 245. Tank is super young at 40 days and Im not worried as the corals are doing well and I have no fish so not trying to chase a number, but trying to understand why. The biggest animals are a sea cucumber and a mantis and both are still alive.

I added a bunch of pods this week and introduced new salt mix, but salt mix seems unlikely as its being added at ~1% a day. Any ideas?

jmaneyapanda · 2026-10-31T13:27:24-0400

Yes. But I honestly wouldnt even focus on ORP. It will be affected by things that are functionally inconsequential to how you care for your tank.

Mr.BobDobalina · 2026-10-31T13:36:16-0400

jmaneyapanda said:
Yes. But I honestly wouldnt even focus on ORP. It will be affected by things that are functionally inconsequential to how you care for your tank.

Thanks for the reply. I don't really "focus" on it other than a sign of something dying or a canary in the coal mine. I just have never dosed phyto so its new to me and I like to understand the "why." If pods are happy, Im happy!

jmaneyapanda · 2026-10-31T13:47:19-0400

Mr.BobDobalina said:
Thanks for the reply. I don't really "focus" on it other than a sign of something dying or a canary in the coal mine. I just have never dosed phyto so its new to me and I like to understand the "why." If pods are happy, Im happy!

The "why" is based on what ORP truly is. The oxidative-reductive potential. The ability to gain or lose electrons. Due to the way most organics are biochemically built, they push towards a low ORP. Thats why foods, your hand, a dead fish, etc will cause a plummet in ORP. Again, doesnt mean anything really in terms of functional care of your aquarium (aside from a dead fish, LOL). Unless youre dosing ozone, Id use ORP exactly as you mentioned- as a barometer measuring trends. The numerical values themselves arent going to be really useful.