Does ORP still decrease if you add H2O2 to sterile seawater?

[Miami Reef]

Does ORP still decrease if you add H2O2 to sterile seawater?

Perhaps syringe filtering seawater into .22um filter. Does anyone know if ORP will still decrease?

Some people sterilize seawater with bleach and neutralize to make a phytoplankton culture. Could that be used in the sterile water test?

 

[Dan_P]

Does ORP still decrease if you add H2O2 to sterile seawater?

Perhaps syringe filtering seawater into .22um filter. Does anyone know if ORP will still decrease?

Some people sterilize seawater with bleach and neutralize to make a phytoplankton culture. Could that be used in the sterile water test?

@taricha?

 

[taricha]

Does ORP still decrease if you add H2O2 to sterile seawater?

Perhaps syringe filtering seawater into .22um filter. Does anyone know if ORP will still decrease?

Yes. ORP measurement should still drop because the effect is (probably) about the h2o2 changing the oxidation state of stuff on the probe itself.

Here's my best understanding...

https://www.reef2reef.com/threads/t...ing-h2o2-into-a-saltwater.848998/post-9316683

 

[Miami Reef]

Thank you, Taricha. That makes sense. It never really made sense to me how dying bacteria can be the main cause of ORP reduction upon adding H2O2. There just isn’t enough bacteria concentrated near the probe, nor does H2O2 kill bacteria that quick to cause an instant ORP drop upon addition.

 

[taricha]

That makes sense. It never really made sense to me how dying bacteria can be the main cause of ORP reduction upon adding H2O2. There just isn’t enough bacteria concentrated near the probe, nor does H2O2 kill bacteria that quick to cause an instant ORP drop upon addition.

eh, ORP is weird. It can react to tiny amounts of materials like trace metals.
Also h2o2 in sufficient doses can cause red cyano in a beaker to like pink pigment to the water, so there's some cell disruption.
Just saying these are also reasonable things that may happen. But like I said, mostly it looks like a local probe effect and conditioning the ORP probe differently can change it.

 

[Miami Reef]

But like I said, mostly it looks like a local probe effect and conditioning the ORP probe differently can change it.

Hmm. I thought ORP doesn’t decrease when adding it to pure H2O2. If true, that should debunk the actual probe reacting with the peroxide?

I think it has something to do with seawater.

 

[Miami Reef]

Also h2o2 in sufficient doses can cause red cyano in a beaker to like pink pigment to the water, so there's some cell disruption.

I’m not denying that H2O2 can kill cells and organisms. I don’t have cyano, and my short test with H2O2 also brought down ORP.

Using sterile seawater to remove bacteria as a variable is what this thread was originally about. :)

Seems like ORP still decreases, so it’s probably trace elements or something in seawater.

 

[taricha]

I think it has something to do with seawater.

exposure to seawater over time seems to reliably condition probes to have that H2O2 drop.
Lasse's new probe in seawater didn't have the same behavior with h2o2 during the "break-in" period.

 

[Jay Hemdal Verified Community Expert]

Does ORP still decrease if you add H2O2 to sterile seawater?

Perhaps syringe filtering seawater into .22um filter. Does anyone know if ORP will still decrease?

Some people sterilize seawater with bleach and neutralize to make a phytoplankton culture. Could that be used in the sterile water test?

In my bench testing, with a portable ORP probe, I saw a slight rise in ORP after peroxide additions in sterile seawater and also in the presence of algae. My hypothesis was that there would be a larger rise in ORP…… but there wasn’t.

Measuring ORP can be problematic due to probe calibration and condition, and portable probes can give different readings than dedicated probes.

https://www.reef2reef.com/ams/hydrogen-peroxide-bench-testing.803/
Jay

 

[GARRIGA]

In my bench testing, with a portable ORP probe, I saw a slight rise in ORP after peroxide additions in sterile seawater and also in the presence of algae. My hypothesis was that there would be a larger rise in ORP…… but there wasn’t.

Measuring ORP can be problematic due to probe calibration and condition, and portable probes can give different readings than dedicated probes.

https://www.reef2reef.com/ams/hydrogen-peroxide-bench-testing.803/
Jay

Have a portable pen style probe from HM Digital. Are you saying that’s more reliable than were I to use an in tank solution such as with Apex or Hydros? Goal was to use the latter just to track trends. Use the portable which can be calibrated with their solution to test accuracy of in tank. At least that’s my assumption until I actually start testing with them. Mostly for utilizing peroxide for various test but also curious how trends change day and night as I feed or go periods fasting. Semi mad scientist fun

 

[Miami Reef]

exposure to seawater over time seems to reliably condition probes to have that H2O2 drop.
Lasse's new probe in seawater didn't have the same behavior with h2o2 during the "break-in" period.

Ah. Very interesting! Thanks!

 

[Randy Holmes-Farley Verified Community Expert]

Hydrogen peroxide can be both an oxidizer and a reducer in seawater. It is known to reduce copper in seawater from Cu++ to Cu+, which reduces ORP. It may do the same for some other trace elements.

 

[Jay Hemdal Verified Community Expert]

Have a portable pen style probe from HM Digital. Are you saying that’s more reliable than were I to use an in tank solution such as with Apex or Hydros? Goal was to use the latter just to track trends. Use the portable which can be calibrated with their solution to test accuracy of in tank. At least that’s my assumption until I actually start testing with them. Mostly for utilizing peroxide for various test but also curious how trends change day and night as I feed or go periods fasting. Semi mad scientist fun

I’m not sure what the exact issue is with portable ORP probes, but I think it has to do with the amount of time these probes need to stabilize and give accurate readings. I find that my inline probes that are always running give better results overall. I’ve pretty much stopped relying on quick ORP measurements to tell me much - but they do react to large changes.