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

[Lasse]

Follow up - i dose 5 ml there I always dose. First for the two probes that in the beginning not show any dip when I dose H2O2. Been in the aquarium for 1 month now (around)

And Probe A - been in the aquarium for more than 2 years

At least in my aquarium - the dip is depending on time in my aquarium

Sincerely Lasse

 

[Lasse]

An Update

Filled up the oxydator today

The old in the sump

Up in the aquarium (B and C)

Its clear that at least in my aquarium has this "ORP drop" to do with tiime in my aquarium.

I will do another stress test with adding peroxide direct in the aquarium when levels has gon back to normal.

Sincerely Lasse

 

[Lasse]

Last test with adding 10 ml directly in the DT Redox C up in the DT - direct reaction

Redox B up in the DT - also direct action. Both these electrodes did not show this behavior when they was new
'

Redox A in the sump Direct action too

I´ll think that I have prove that this odd behavior of ORP probes when adding H2O2 into the water is age depending. What it means - do not ask me

I will now end this test and take away all extra redox probes. Only use my old in the DT and my old in the bottom of my DSB.

Sincerely Lasse

Siincerely Lasse

 

[Lasse]

In this test we have concentrate on ORP potential in open water there is rathe positive but mayb not as useful as it is if you want to manage an anaerobic filter. In my tank I pump water from the bottom of my DSB and up. I can also add a carbon source in the bottom in order to favour denitrification. After very much of trials I have succeeded to balance my ORP in the bottom water of my DSB to vary between -100 and -60 mV. I use one real ORP electrode and on virtual. The real manage the flow through the bed and the virtula manage addition of ethanol. On a daily base I use around 7 ml 8% ethanol and pump around 500 L backwards in the DSB

For the moment - NO3 is around 7.5 mg/L and NO2 around 0.0.3 mg/L. I will go down to around -100 in ORP

Sincerely Lasse

 

[DrZoidburg]

I like this, is how I use my orp for sulfur reactor. My orp if accurate went from steady 100 to now 350. Telling me I either need to clean probe, change flow, or add more media. Apex doesn't go negative I think. Other one I have goes -999. Used to read about -100. It was good but making water too acidic so I took some out a few month ago. I don't think bacteria Kaput It is still working.

 

[Randy Holmes-Farley]

I´ll think that I have prove that this odd behavior of ORP probes when adding H2O2 into the water is age depending. What it means - do not ask me

Hi Lasse,

Can you summarize the age effect you are talking about? I'm not really following it from the graphs.

 

[Lasse]

Yes

This graph are from august and my old ORP electrode (+3 years) The drop is after addition of 10 ml H2O2 in the DT ((probe A)

The same electrode yesterday after addition of 10 ml H2O2 the same way (probe A)

Is around the same result - a huge ORP drop

August 21 I placed two 14 days used ORP electrodes in my DT and did an addition of 10 ml H2O2

The old in the sump (probe A) react as above with a huge dip. Probe B (14 days used) did nor react at all to the H2O2 addition (red circle)

Neither did Probe C - also 14 days used Addition of 10 ml H2O2 at the red circle

August 25 - this result - old probe A (10 ml H2O2 addition

Probe B - no dip

Probe C no dip

Sept 20

Probe A - 5 ml addition - normal dip

Sept 20 Probe B erratic -

sept 20 Probe C - NOW a clear dip

Nov 15 Probe A - still a dip

Nov 15 Probe B - a clear dip

Nov 15 Probe C - a clear dip

This shows that the 2 new probes may take around 1 month before they act as an old probe - show a dip when 5 ml H2O2 is added.

Sincerely Lasse

 

[Randy Holmes-Farley]

Nice.
These are platinum probes?

Seems logical to conclude that the probes are slowly acquiring something on their surface that interacts with H2O2 or a product of H2O2 in seawater that drops ORP.

Might be whole organisms on the probe that are induced to drop ORP somehow, or a redox active metal (e.g., copper or manganese) bound to organics that are bound to the probe surface, that cause the observation.

I'd lean toward the latter as more likely.

 

[Lasse]

Nice.
These are platinum probes?

I´ll think so - it is GHL:s redox probe

Seems logical to conclude that the probes are slowly acquiring something on their surface that interacts with H2O2 or a product of H2O2 in seawater that drops ORP.

Might be whole organisms on the probe that are induced to drop ORP somehow, or a redox active metal (e.g., copper or manganese) bound to organics that are bound to the probe surface, that cause the observation.

I'd lean toward the latter as more likely.

Yes - because I can also see that the readings get lesser erratic with time too - which indicate that something slow down the reaction time. I now and then also clean my old electrode with a toothbrush - the red markings. Something is taken away - readings get more erratic - but the ORP dip is not affected by the toothbrush cleaning at all 10 days after the cleaning (blue marking) - indicating that it can be an electric-chemical bound on the electrode that a toothbrush do not take away that a responsible for the dip


Next cleaning - I will test with a H2O2 addition directly

Sincerely Lasse

 

[shwareefer]

I'll admit upfront I did not read this thread. I'm just curious @Lasse what these results of my ORP mean to you? I've been cleaning some algae off plugs with H2O2 and you can see the three strong dips each time. However as you can see the last two times were peaks instead. If this has been adressed in this thread just tell me to read it lol. Thanks.

 

[Lasse]

Have you change (or deep cleaned) your probe between the dips and the peaks?

Sincerely Lasse

 

[shwareefer]

Have you change (or deep cleaned) your probe between the dips and the peaks?

Sincerely Lasse

Nope haven't touched the probe in 6 months. I did a few more plugs today with H2O2 and it dipped downward again.

 

[Randy Holmes-Farley]

The dip was in tank water? New salt water? Hydrogen peroxide only added, nothing else with it?

 

[shwareefer]

The dip was in tank water? New salt water? Hydrogen peroxide only added, nothing else with it?

I just spray the plugs with peroxide, maybe brush any larger algae bits, let it drip off and return to tank. No rinsing except in the tank with a swoosh near my overflow. The probe is in my second sump chamber after the skimmer so would get exposed pretty much instantly.

 

[Randy Holmes-Farley]

OK, thanks. That's a little harder to know the processes involved than simple dosing since the high peroxide concentration used to kill algae likely released their low ORP intracellular contents as well.

 

[Lasse]

I have seen a pattern in the ORP level between my filling of my Oxydator and the resulting ORP levels. The pattern is that if the oxydator have been empty for a while - a filling provoke a huge dip that slowly rise and when the oxydator is empty - ORP rise a lot. If I fill it a day after its empty - the dip will not be as huge as before and the rise into high levels of ORP will be faster. Turquoise = filling - Red Oxydator is empty

Sincerely Lasse

 

[Randy Holmes-Farley]

Thanks Lasse. Very interesting.

 

[Lasse]

Thanks Lasse. Very interesting.

Yes it is and I will follow this up for the coming months - maybe it can give us some explanations and deeper understanding how H2O2 dosing works. The way i use my Oxydator (High concentration and 3 catalyst) is more as an automatic doser of H2O2 than an oxygen producer (I get oxygen too but also som H2O2 out in the water.

Sincerely Lasse

 

[Hans-Werner]

Lasse, I am sorry, I don't recall whether the question has already been answered what causes the sawtooth curve. Is it only the daily vitamin addition? Or are there other diurnal effects?

 

[Lasse]

Lasse, I am sorry, I don't recall whether the question has already been answered what causes the sawtooth curve. Is it only the daily vitamin addition? Or are there other diurnal effects?

The daily pH swing

Sincerely Lasse