Questions about UV and Ozone together

[Randy Holmes-Farley]

I don't know where it comes but the phosphate drops happens every time I use ozone, I tried it multiple times, I'm very sure about it as I always struggle with high levels but every times I use ozone I drops fast, it is so effective that then I have to dose it. When I stop it phosphate increase

I don’t doubt it happens in your tank, I just cannot think of any simple reason and have not heard anyone else report it. I did not track it in my tank.

Wild ideas might relate to increased bioavailability of a trace element that allows something to grow faster, using more phosphate.

 

[Miami Reef]

I haven’t noticed any correlation between phosphate and ozone in my tank.

 

[Superlightman]

I haven’t noticed any correlation between phosphate and ozone in my tank.

You run it all day and how much?

 

[Miami Reef]

You run it all day and how much?

I run it 1 day per week. I use an air drier and inject it into my skimmer at about 120-130mg/hr into my 260 gallon tank.

Here’s an example of my ORP when I use the ozone :

Yes, the ORP was a little higher than I’d like it to be in this example. I lowered the output after checking the APEX. I didn’t notice any harm. Phosphate never changes with ozone for me.

 

[Superlightman]

Sure for one day per week or only you will see no effect on phosphate levels, but if you use it every day you will see it.

 

[Miami Reef]

Sure for one day per week or only you will see no effect on phosphate levels, but if you use it every day you will see it.

I’m not sure what difference one day vs every day will make. A drop is a drop. Why would phosphate rise back up when stopping ozone, assuming food import is normal?

That’s like saying I won’t see my phosphates drop if I only use GFO 1 day per week vs every day. Surely they’ll drop with both usages, maybe more with every day, but still should be significant if only using it one day a week at a higher concentration.

The science doesn’t show any direct interaction between phosphate and ozone. Perhaps it’s indirect like Randy said, or maybe the increase in light penetration is increasing the demand for phosphate in photosynthetic organisms.

 

[Superlightman]

No you can't absolutely not compared it to gfo as it not absorbe phosphate and you need to wait a few days to see the effect. I don't know how it works but it works, it is one of the most potent tool I had to reduce it

 

[gbroadbridge]

Sure for one day per week or only you will see no effect on phosphate levels, but if you use it every day you will see it.

I run ozone 24/7 and don't see any effect on Phosphate.

It is likely that there is something unusual in your tank that reacts either to the reduction of 'something' or to the creation of 'something' by the ozone.

 

[Miami Reef]

I run ozone 24/7 and don't see any effect on Phosphate.

It is likely that there is something unusual in your tank that reacts either to the reduction of 'something' or to the creation of 'something' by the ozone.

Or maybe coincidence and something unrelated to ozone.

 

[Superlightman]

But I tried it in two tanks off and on and everytime same happened, maybe you not put enough, how much you put?

 

[Randy Holmes-Farley]

But I tried it in two tanks off and on and everytime same happened, maybe you not put enough, how much you put?

How are you using ozone?

 

[Superlightman]

How are you using ozone?

I used it in continuous 24h.now it reduce as I used an oxydator, wich make the water also clear but as no effect on the phosphate level

 

[Randy Holmes-Farley]

I used it in continuous 24h.now it reduce as I used an oxydator, wich make the water also clear but as no effect on the phosphate level

I don’t think there is any simple explanation for your observations.

 

[Superlightman]

I don’t think there is any simple explanation for your observations.

Maybe because it makes the skimmer more effective ?

 

[Miami Reef]

Maybe because it makes the skimmer more effective ?

If anything, it decreases the skimmer’s effectiveness.

Another result of breaking some organics into smaller, more hydrophilic bits (Figure 3 and 4) is that it often increases their bacterial biodegradability.27-29 Therefore, the ozone may need only to start the degradation process, and bacteria in the aquarium can finish off the organics by uptake and metabolism.

This process may, in fact, be why some aquarists report drops in nutrient levels after initiating ozone. It is not because ozone directly impacts either nitrate or phosphate (it does not react directly with either), but the newly bioavailable organics may drive bacterial growth, just as adding ethanol (e.g., vodka) or sugar might. The growing bacteria need nitrogen and phosphate, and if they satisfy those needs by taking up nitrate and phosphate, the levels of those nutrients in the water may drop. That effect, however, may be only temporary as the initial burst of new bioavailable organics winds down, and a new stable state is reached with lower levels of organic material and similar levels of inorganic nutrients.

Years ago it was widely claimed that ozone use increased skimming, and I claimed then that I didn't see how that could happen directly. Most organic compounds likely to be found in significant quantities in a reef aquarium will become more polar and likely less skimmable after it reacts with ozone. Figure 3, for example, shows how oleic acid (readily skimmed) gets converted into more polar compounds that will not be so readily skimmed as they will not be as strongly attracted to an air water interface.

A small portion of organic molecules in reef aquarium water may become more skimmable if, for example, they become more hydrophobic after reaction with ozone. They may also become more skimmable if they were totally hydrophobic before ozone and were transformed into molecules with polar and nonpolar parts (called amphiphilic) which more readily absorb onto an air water interface and are skimmed out.

The remaining organics would then be removed more by bacterial processes than before the initiation of ozone in the same aquarium.

All of this information can be found in this article: http://www.reefkeeping.com/issues/2006-03/rhf/index.php#11

 

[Randy Holmes-Farley]

Maybe because it makes the skimmer more effective ?

This is from one of my ozone articles:

Oxidation of Organics by Ozone: Skimming and Nutrients

---

Another result of breaking some organics into smaller, more hydrophilic bits (Figure 3 and 4) is that it often increases their bacterial biodegradability.27-29 Therefore, the ozone may need only to start the degradation process, and bacteria in the aquarium can finish off the organics by uptake and metabolism. Large humic acid molecules, for example, are converted by ozonation into smaller fragments that are more readily taken up and metabolized.29 This process may, in fact, be why some aquarists report drops in nutrient levels after initiating ozone. It is not because ozone directly impacts either nitrate or phosphate (it does not react directly with either), but the newly bioavailable organics may drive bacterial growth, just as adding ethanol (e.g., vodka) or sugar might. The growing bacteria need nitrogen and phosphate, and if they satisfy those needs by taking up nitrate and phosphate, the levels of those nutrients in the water may drop. That effect, however, may be only temporary as the initial burst of new bioavailable organics winds down, and a new stable state is reached with lower levels of organic material and similar levels of inorganic nutrients.

Skimming is a complex process that has many subtleties. The previous sections have discussed how ozonation modifies organic molecules , and we can then extrapolate how those processes impact skimming. Years ago it was widely claimed that ozone use increased skimming, and I claimed then that I didn't see how that could happen directly. Most organic compounds likely to be found in significant quantities in a reef aquarium will become more polar and likely less skimmable after it reacts with ozone. Figure 3, for example, shows how oleic acid (readily skimmed) gets converted into more polar compounds that will not be so readily skimmed as they will not be as strongly attracted to an air water interface.

A small portion of organic molecules in reef aquarium water may become more skimmable if, for example, they become more hydrophobic after reaction with ozone. They may also become more skimmable if they were totally hydrophobic before ozone and were transformed into molecules with polar and nonpolar parts (called amphiphilic) which more readily absorb onto an air water interface and are skimmed out.

Are there other ways that skimming might be increased besides these two processes? I hypothesized in a previous article that it was due to the growth of bacteria (either in the water itself, or bound to surfaces), and possibly also the release of new organic molecules as they grew, that caused the effects some aquarists observed.

It seems as if the tide of opinion has turned, however, and most aquarists now claim that the amount of skimmate is reduced significantly when using ozone. Many claim that the collection of skimmate has nearly stopped in their aquaria when starting ozone. Why the difference compared to past opinion? That's hard to say, and may depend on the types and qualities of the skimmers available now compared to years ago, as well as changes in other husbandry practices. In any case, the overriding experience of many aquarists today is that skimming is reduced, and the presumed reason is that the organics are being made chemically less skimmable by ozone. The remaining organics would then be removed more by bacterial processes than before the initiation of ozone in the same aquarium.

 

[Superlightman]

bacteria breaking down that could be an explanation, but same time ozon is knowed for reduce them isn't it contradictory?
I also see that the skimming was strongly reduced but it was also way more dark,it seemed to be more concentrated

 

[Miami Reef]

bacteria breaking down that could be an explanation, but same time ozon is knowed for reduce them isn't it contradictory?
I also see that the skimming was strongly reduced but it was also way more dark,it seemed to be more concentrated

My skimmer wasn’t darker, but it was more slimy and gunky. I saw beige globs inside the cup.

 

[Randy Holmes-Farley]

bacteria breaking down that could be an explanation, but same time ozon is knowed for reduce them isn't it contradictory?
I also see that the skimming was strongly reduced but it was also way more dark,it seemed to be more concentrated

Ozone is not known for reducing bacteria, despite the common belief. From the same article:0

Reducing Bacteria When Using Ozone

---

Bacteria and other organisms suspended in water can be killed by adequate exposure to ozone. That process is widely used to disinfect drinking water and wastewater in a variety of applications. The doses and exposures of ozone required for disinfection, however, are quite high. They are higher than are used in reef aquarium applications, where typical doses of ozone range up to about 0.3 ppm in typical contact chambers, and last for only a few seconds. Consequently, aquarists must be careful when translating disinfection literature to reef aquarium effects.

In a recent study of a recirculating seawater system,35 the dosing of 0.52 ppm of ozone was tested for its ability to decrease the system's bacterial load. That dose is similar to a 300 mg/hr ozone unit applied to a typical small skimmer flow rate of 150 gallons per hour (568 L/h). In this experiment, the levels of suspended bacteria (both Vibrio and coliform) were analyzed in a variety of locations (intake, pre-ozone, post-ozone, pre-tank, and post-tank). In no case was there a statistically significant reduction in bacteria. Even the addition of a venturi injector to the contact chamber did not adequately help (although it trended toward fewer bacteria, the result was not statistically significant). For comparison purposes, at higher ozone concentrations and contact times (5.3 ppm ozone for 240 minutes), Vibrio vulnificus is easily killed, with fewer than one in a hundred million of the initial bacteria remaining.36

How much ozone, and for how long, is required to kill suspended organisms in seawater? In one study of a suspended dinoflagellate algae (Amphidinium sp. isolated from Australia's Great Barrier Reef), it was found that 5-11 ppm ozone for six hours of exposure was required to kill 99.99% of the organisms.37 While that kill rate is impressive, that exposure is far higher than is ever achieved in a reef aquarium application. Lower doses and shorter contact times had smaller effects. A dose of 2 ppm and a short contact time (with the time not stated in the paper) showed a reduction in bacteria of abut 98% (which is still quite significant, but would not be referred to as disinfection).

Similar results were found for the spores of the bacterium Bacillus subtilis.38 In this case, doses of 14 ppm ozone for 24 hours were required to kill 99.99 percent of the spores. In another study 99.9% of fecal coliforms, fecal streptococci and total coliforms were killed with 10 ppm ozone and a contact time of 10 minutes.39 The exposure of Vibrio species and Fusarium solani (bacteria that are pathogenic to shrimp) to 3 ppm ozone for five minutes killed 99.9% of the bacteria.40Water from a seawater swimming pool was effectively sterilized using 0.5-1.0 ppm ozone in a contact tower.41

The data for the disinfection of freshwater systems are much more extensive, and so include more data at lower contact times and concentrations. In one experiment at a Rainbow trout hatchery, the addition of 1-1.3 ppm of ozone with a contact time of 35 seconds reduced heterotrophic bacteria in the aquarium water itself by about 40-90%.42

Does the ozone used in a typical reef aquarium application reduce bacteria? Maybe, but certainly not to the extent required for disinfection. Still, a reduction of 50% of the living bacteria could have significant effects. The above study in the trout hatchery showed that the use of ozone at several times the typical reef aquarium rate and for about five to ten times the typical contact time results in such a drop. While the data are unavailable, I expect that the bacteria in the water exiting a normal reef aquarium's ozone application are not decreased by as much as 50%.

It seem reasonable to conclude from such literature studies that most bacteria that enter the ozone reaction chamber in a typical reef aquarium application will not be killed by ozone or its byproducts. If killing bacteria in the water column is a goal, then a UV (ultraviolet) sterilizer may be more useful.

 

[Superlightman]

Thanks interesting article