I´ll try to explain the oxydator the way I understand it. Details can be wrong but I think I know the basic rather well
You fill up the plastic container with peroxid between 3 and 12 % strength In this case they use two catalysts - but all from 1 to whatever works.
When you add the peroxide the process starts with help of the catalysts. H2O2 will be broken down to water and different form of oxygen radicals - in some cases depending on the catalyst. In this closed container - the result will be oxygen gas in the end. The gas will form a layer above the peroxide - as more gas will be produced - the pressure from the gas bubble in the top of the acrylic container will press non-catalyzed peroxide outside the acrylic container. (red lines). How fast the gas-bubble in the acrylic container will expand. hence press out more or lesser un catalyzed H2O2 outside the container depends on the H2O2 concentration and the amount of catalysts. Higher percent and more catalysts - more un catalysed H2O2 will be pressed out per time unit. This is valid for temperature too - higher temperature - faster reactions per time unit. In this case - the A-type - the un catalysed H2O2 will pas by the ceramic container (tonbecher). This serve as an catalysts too and if the rate of un catalysed H2O2 is low enough - all will be converted to oxygen gas. The oxydator serve as an source for oxygen in the aquarium.
In my case - it is my reserve if I get a power breakdown. Normally it is in my sump but in case of power break down - I move it to the DT.
Of interest for me is was happen with the H2O2 that will past through the both "catalysts chambers" and end up as H2O2 in the water column. It will be breaken down with help of different compounds - iron is one. In this case oxygen radicals like single O atoms, HO radicals and HOO radicals will be formed. These radicals will oxidize whatever it encounter including organic matter. This is the way it works on yellow substances (read humic acids). But oxygen radicals does not differentiate between living and dead organic matter - it will oxidize the thing its first encounter. Therefore - the higher concentration of un catalyzed H2O2 that slips through the ceramic container - the higher is the statistic chance that it damage living organism behind their ability to repair. its a balance act. Can it be metered?
In comparison with the other method using oxygen radicals - ozone - the redox potential is tricky in this case. If you add pure H2O2 (or to much slips past the ceramic in the outer container) you will see a rather huge decline of redox potential - followed of a rise up to the level before and higher. The chart below is interesting in order to show this and that H2O2 can be mor persistent in our water compared with former thoughts (a matter of hours before total conversion). I have heard people working with peroxide as an antiworm agent in fish farms saying the same - it will exist longer than we think. My graph can give some suport for that claim
From the left - normal variation depending on pH. The fast decline around 2021-01-03 caused of an attempt of me to eradicate some aiptasia. I add around 30 ml 12% H2O2 in one of my BTN modules there one of my Wavemakers are hidden (yes I need no comments about that decision - even the sun have patches
) My tank is around 300 L (80 G).
However - it gave me a beautiful graph and maybe some more understandings of the mechanisms involved. H2O2 is a oxidizing agent - why will adding fresh H2O2 result in a dip of redox potential - it should be the opposite as with ozone. The small blue dots is marking for refilling of the oxydator - there will always be som spill when it restart. The red marked dip is not a refill but I took up the acrylic container and inspect it.
The breakdown of H2O2 is for me two different processes and this can explain these dips and the rise afterwards. By definition - when a compound lose a oxygen atom - it is a reduction and if it gain an oxygen atom - it is an oxidation.
By definition - when H2O2 lose one of its O atoms - a reduction process take place (lower the ORP). On the other hand when the radicals (O, HO and HOO) encounter something it can oxidize - an oxidation take place (higher the ORP). If your redox will decline or rise is therefore depended of which process dominate over the other. When just adde - much H2O2 lose one of its O atoms - a force taking ORP down exist and dominate - The radicals start to oxidize - a force taking ORP up exist and slower or dominate over the reducing process according to ORP. When pure H2O2 in the water column get lower and lower - ORP stabilize and rise to the old level (or slightly higher)
I´m total aware that it could be done thousands of studies in detail but this is my explanation in a macro plane - or could be an explanation.
If I´m right - some H2O2 may have a lifetime around 20 days in an aquarium. I´m aware of that this is one test - I should redo it in order to validate the results - but after the first addition of more than 30 ml 12% H2O2 - my hearth attack was not long away - nearly all of my corals reacts with shrinking and some have not totally recover yet. Fish and other animals - no reactions.
If it should be used - as ozone - together with a skimmer - I do not know. For the moment - I have my oxydator in the same apartment as my skimmer - some will come into the skimmer - bad or good - i do not really know - but it should not been my first choose if I had a possibility to place it on another place.
I have also noted a funny reaction from my pH probe when I move the oxydator to the same part in the sump as I have my probes. My pH shows summer behavior - even if it is a cold winter with very closed windows and doors. High CO2 indoors.
My pH the last year. No other changes and the CO2 levels in the room with my aquarium have warned us about CO2 above 1000 ppm the last days. I moved the Oxydator 2021-01-10. The pH probe is calibrated around 1 of february.
I hope that I at least answered some of your questions.
Sincerely Lasse
