Test if it is possible to explain the know ORP reduction when adding H2O2 into a saltwater

[brandon429]

I like this thread for reviews on in tank work bc its long running

Dinoflagellates my experience......h2o2 reefing tool!!!!!

aaaaaaarrrrrrr just wanted to share my recent battle and how i won!!!!!!!!! "i wish i took pics but i didn't..:(" so about 3 weeks ago my tank broke out pretty bad i mean bad!!!!!! my coast to coast overflow would get plugged and almost overflow my tank..... so i did my research and found...

www.reef2reef.com

post there we can review details on h202 and even better ways than adding peroxide into the water. This thread by Lasse is for ORP testing

 

[Lasse]

Forget the light theory - did not believe in it very much - but now we have let that explanation out in the drain. Old electrode in the DT

The new electrode (in the DT) is still very noisy - and no reaction on H2O2 addition

Sincerely Lasse

 

[taricha]

Forget the light theory - did not believe in it very much - but now we have let that explanation out in the drain

Does this mean that you did that test after hours of darkness and the ORP drop still happened (but when it was kept in a bucket for hours, the ORP drop disappeared)?

 

[Lasse]

Does this mean that you did that test after hours of darkness and the ORP drop still happened

Yep - I did that in my DT with one old electrode and on new. Both in the DT - 5 cm apart from each other. The light have been off for 1.5 hours when the test was done. I will have the new electrode in the tank for a while and see if it get stable - my experiences from the past says so. I have change my test in the post above in order to make it more clear. I´m testing Hans Werner´s biofilm explanation.

Sincerely Lasse

 

[Hans-Werner]

Lasse, good morning,
What you describe as "noise" may be the true ORP fluctuations in the tank while the "stabilization" also is a biofilm effect. Biofilm growth after a week or two = "stabilization" of new electrode.

 

[Lasse]

Lasse, good morning,
What you describe as "noise" may be the true ORP fluctuations in the tank while the "stabilization" also is a biofilm effect. Biofilm growth after a week or two = "stabilization" of new electrode.

That explanation have cross my mind - however can´t exclude a faulty probe or port yet. If it stabilize itself - I can see two explanation

1) it takes time for the internal fluids to stabilize against the water (IMO - often seen in new pH probe that normally demand a re-calibration after 2 weeks)

2) the biofilm theory

In order to sort that out - I will clean the old electrode with ethanol when (if) the new will stabilize itself

For the moment - IMO - there is no indication that the biofilm theory is wrong. But Rome was not build i one day so I take it slow but steady.

Sincerely Lasse

 

[Lasse]

Interesting observations of redox not linked to H2O2 addition. Since a while ago - I have an automatically feed of cyclops 10:00, 10:30, 11:00. 12:00, 13:00, 14,00, 15:00, 16:00, 17:00, 18:00 and a manual feeding 21:00. It is frozen ctclops that I place in a bottle every day and my dose pump pump out small amounts at above mentioned hours.

I can see these feeding in my redox charts - this is for yesterday. Red staples - automatic feeding, red circle - hand feeding

Sincerely Lasse

 

[Rick Mathew]

Interesting observations of redox not linked to H2O2 addition. Since a while ago - I have an automatically feed of cyclops 10:00, 10:30, 11:00. 12:00, 13:00, 14,00, 15:00, 16:00, 17:00, 18:00 and a manual feeding 21:00. It is frozen ctclops that I place in a bottle every day and my dose pump pump out small amounts at above mentioned hours.

I can see these feeding in my redox charts - this is for yesterday. Red staples - automatic feeding, red circle - hand feeding

Sincerely Lasse

I have exactly the same on my daily frozen food feeder...See below

 

[Dan_P]

I have exactly the same on my daily frozen food feeder...See below

I am wondering about these spikes. Very close to being identical in trough depth and width. The instantaneous nature does not seem to fit a physical phenomenon like mixing a small amount solid to a large amount of water. I am surprised that the response time is not much broader. Lasse’s wave forms are closer to what I expect though I still wonder about the relatively quick rebound. How to investigate these feeding ORP bounces?

I would be inclined to think these bounces were not instrument fluke if the bounce were reproduced and dose dependent in a small volume of tank water stirred in a beaker (Not sure whether glass or plastic beaker is best). Good mixing and rapid addition of whatever you test is important to minimize mixing effects. @ taricha has worked with ORP and bleach and will be better informed on this.

At the same time, the question of the biofilm effect could be addressed by storing the cleaned probe in the aquarium and testing it daily in the beaker setup. Biofilms start forming quickly. Day 0 vs day 1 may show something.

 

[taricha]

I am wondering about these spikes. Very close to being identical in trough depth and width. The instantaneous nature does not seem to fit a physical phenomenon like mixing a small amount solid to a large amount of water. I am surprised that the response time is not much broader. Lasse’s wave forms are closer to what I expect though I still wonder about the relatively quick rebound. How to investigate these feeding ORP bounces?

Rick's and Lasse's graphs are on very different time scales.
As for the instantaneous nature of these ORP shifts, all I can say is electrochemistry is weird...

I think the times I've seen people post their ORP drops from peroxide it's nearly instant.

Yes - It less than a minute - even when I dose in the DT and the probe is in the sump.

I would be inclined to think these bounces were not instrument fluke if the bounce were reproduced and dose dependent in a small volume of tank water stirred in a beaker (Not sure whether glass or plastic beaker is best). Good mixing and rapid addition of whatever you test is important to minimize mixing effects. @ taricha has worked with ORP and bleach and will be better informed on this.

ORP moves from either bleach & KMnO4 (up) or thiosulphate down are very much dose dependent in my experience.
ORP moves from h2o2 usually aren't dose dependent. Doses in the "normal" range of what people add move the ORP down (or up for me) and following with another dose shortly after gives essentially no additional changes.
Downward moves from food and phyto I don't know.

At the same time, the question of the biofilm effect could be addressed by storing the cleaned probe in the aquarium and testing it daily in the beaker setup. Biofilms start forming quickly. Day 0 vs day 1 may show something.

I left my probe in from day 1 to weeks. The ORP rose (my water is weird in this respect) with h2o2 addition each time regardless. My probe is a single-junction not double. But no amount of digging into probe construction revealed much of anything.

 

[Rick Mathew]

I am wondering about these spikes. Very close to being identical in trough depth and width. The instantaneous nature does not seem to fit a physical phenomenon like mixing a small amount solid to a large amount of water. I am surprised that the response time is not much broader. Lasse’s wave forms are closer to what I expect though I still wonder about the relatively quick rebound. How to investigate these feeding ORP bounces?

I would be inclined to think these bounces were not instrument fluke if the bounce were reproduced and dose dependent in a small volume of tank water stirred in a beaker (Not sure whether glass or plastic beaker is best). Good mixing and rapid addition of whatever you test is important to minimize mixing effects. @ taricha has worked with ORP and bleach and will be better informed on this.

At the same time, the question of the biofilm effect could be addressed by storing the cleaned probe in the aquarium and testing it daily in the beaker setup. Biofilms start forming quickly. Day 0 vs day 1 may show something.

This occurs as a consequence of "dosing" approx. 50mL of a solution of 35ppt salt water with .5% Citric Acid--->5% Ascorbic Acid---.05% Calcium Propionate----.05% Sorbic Acid (This is a preservative for fish storage) .

This is the solution that my frozen food (Brine, Mysis, PE Calanus and Reef Chili) "slurry" is stored in and "dosed" daily at the same time every day. The slurry is stored at between 30F and 34F. I have been doing this for over 2 years now and have seen the same ORP response....Actually it is useful to know if the feeder is working when I am not around ....

So all that being said I look at the uniform trough depth and an indicator of fairly precise dosage of the slurry and the narrow narrow response time as a indicator that my water circulation system is good...The response time from the time of the add to the bottom of the trough is almost always 20 min...Recovery time is generally 5 hours...My ORP probe is cleaned every month with .34% HCL and a soft toothbrush....I generally see an increase of 15-20 points after cleaning...My average ORP is 292 (measurement is recorded every day)...

 

[Randy Holmes-Farley]

.The response time from the time of the add to the bottom of the trough is almost always 20 min...Recovery time is generally 5 hours...My ORP probe is cleaned every month with .34% HCL and a soft toothbrush....I generally see an increase of 15-20 points after cleaning...My average ORP is 292 (measurement is recorded every day)...

That result and timing makes perfect sense to me.

 

[Rick Mathew]

That result and timing makes perfect sense to me.

That is the first time anyone has ever accused me of making perfect sense...A breakthrough!!!

 

[Dan_P]

Rick's and Lasse's graphs are on very different time scales.
As for the instantaneous nature of these ORP shifts, all I can say is electrochemistry is weird...






ORP moves from either bleach & KMnO4 (up) or thiosulphate down are very much dose dependent in my experience.
ORP moves from h2o2 usually aren't dose dependent. Doses in the "normal" range of what people add move the ORP down (or up for me) and following with another dose shortly after gives essentially no additional changes.
Downward moves from food and phyto I don't know.


I left my probe in from day 1 to weeks. The ORP rose (my water is weird in this respect) with h2o2 addition each time regardless. My probe is a single-junction not double. But no amount of digging into probe construction revealed much of anything.

Hydrogen peroxide “works” via free radicals, bleach and MnO4- generally don’t. We should look at persulfate, another free radical generator, to see what it does to ORP. Even though elevated temperatures are used for a quick oxidation, persulfate can still form persulfate radicals at lower temperature. Try basic persulfate.

How far does an ORP probe have to be from the H2O2 addition point to not see a rapid decline in ORP? If you had a 10 ft PVC pipe, ORP probe at one end and dosed H2O2 at the other end, what would happen? Drill holes every 2 feet for addition points.

 

[Dan_P]

This occurs as a consequence of "dosing" approx. 50mL of a solution of 35ppt salt water with .5% Citric Acid--->5% Ascorbic Acid---.05% Calcium Propionate----.05% Sorbic Acid (This is a preservative for fish storage) .

This is the solution that my frozen food (Brine, Mysis, PE Calanus and Reef Chili) "slurry" is stored in and "dosed" daily at the same time every day. The slurry is stored at between 30F and 34F. I have been doing this for over 2 years now and have seen the same ORP response....Actually it is useful to know if the feeder is working when I am not around ....

So all that being said I look at the uniform trough depth and an indicator of fairly precise dosage of the slurry and the narrow narrow response time as a indicator that my water circulation system is good...The response time from the time of the add to the bottom of the trough is almost always 20 min...Recovery time is generally 5 hours...My ORP probe is cleaned every month with .34% HCL and a soft toothbrush....I generally see an increase of 15-20 points after cleaning...My average ORP is 292 (measurement is recorded every day)...

These details clarify the situation nicely. Still important to see it happen in a beaker and compare the profile with the aquarium profile. It would be nice to know if the effect is dose dependent. Is this what a rabbit hole looks like just as it comes into view?

 

[Lasse]

bleach and MnO4

IMO they works vis free radicals too - but not the same free radicals.

Sincerely Lasse

 

[Dan_P]

IMO they works vis free radicals too - but not the same free radicals.

Sincerely Lasse

I agree, it is not a very clear cut distinction but worth looking into. H2O2 is not behaving like bleach or permanganate with the ORP probe and that I think is the important point.

Persulfate, percarbonate and benzoyl peroxide, off the top of my head examples, might be worth looking at to probe ORP responses to peroxides and radicals. And the response might be strongly influenced by what else is in the medium. For example, would the ORP response to H2O2 be different in a sodium bromide solution?

@taricha mentioned that electrochemistry can seem weird. Free radical chemistry for me is one step above in weirdness and complexity.

 

[Rick Mathew]

These details clarify the situation nicely. Still important to see it happen in a beaker and compare the profile with the aquarium profile. It would be nice to know if the effect is dose dependent. Is this what a rabbit hole looks like just as it comes into view?

Just like this

 

[Dan_P]

Just like this

 

[Lasse]

In my world - free radicals oxidize things and the compounds you mentioned is known to be very strong oxidizer - that make me think that they are "stronger" active radicals (or create more of this sort) than H2O2, May @Randy Holmes-Farley tell us if I´m in the right world or not because I do not know for sure.

Sincerely Lasse