Importance of Dissolved Oxygen?

[NaH2O]

How important is testing for dissolved oxygen? I spoke with someone that saw a presentation a few weeks ago by Eric B. Eric had indicated in the presentation that dissolved oxygen was something we should all be testing for and it is important to test for. Since I didn't get to hear the lecture, and I was getting the information second hand, I'm curious to how important it is. What can we gain from the results of the tests?

 

[Herefishyfishy]

Nikki respectfully, looks like not many feel it's very important. Perhaps this is due to the percentage here that employ high quality skimmers that oxygenate, and huge pumps/power heads to create massive water flow. OMHO

Personally, I would rather upgrade my skimmer or add more flow than spend the big money on an expensive Oxygen monitor. I recall how long it took Brian (slickdonkey) to sell his expensive but cheaply priced oxygen probe.

 

[sihaya]

I think dissolved oxygen is important. But without a dissolved oxygen meter, I'm not sure how easily we can all measure it. Maybe Boomer knows a way.

I know that one way to see if your water might be poorly oxygenated is to test the pH of the water before and after heavily oxygenating it by putting a gallon or so in a bucket with a powerhead for a couple hours. But the chem experts would have to say more about that, because I don't know the details of that method.

When I was at the Backers show, this pretty cool dude (the director of research at Aquarium Pharmaceuticals) was telling me that water is best oxygenated by roll over (i.e. pouring over the edge of something... like it does in an overflow). I don't know if that's true or not, but it got me thinking. I would like to know the more efficient way to oxygenate water. I know Borneman did some tests on his home tanks and he suggests that photosynthesis may be the biggest contributor to oxygen levels in tanks. On that idea, I set up my reverse photoperiod refugium. But I've since had some pretty smart people make me question that idea. So know I'm back to not knowing anything...

When I get the time I want to do some literature research and see if I find anything. Of course, I'll let you all know if I do.

 

[DonW]

You can buy a salifert DO kit or buy a meter. The hobby meters are not very accurate nor are the test kits. I think most folks over test and stress to hard about the results they find. You find yourself making adjustments and fiddling around with things you really cant control thus creating problems or making things worse. I wouldnt worry about it.

Don

 

[sihaya]

But I might argue (just to be annoying), that we freak out over isolated test results because we test too little... not because we test too much.

 

[Curtswearing]

You can buy a salifert DO kit or buy a meter. The hobby meters are not very accurate nor are the test kits. I think most folks over test and stress to hard about the results they find. You find yourself making adjustments and fiddling around with things you really cant control thus creating problems or making things worse. I wouldnt worry about it.

Don

Oh, PULLEEZE!!! Anyone who has known you for some time knows that, not only have you've built a robot to test for DO, you have another one programmed to make modifications, and a third one just to make sure the first robot was right.

 

[cheeks69]

The only time I worry about it is when my tank hits 88 degrees in the summertime and during the wintertime when there's little fresh air coming in and my ph won't rise above 8

 

[Curtswearing]

I own a DO test and I've used it several times. I don't even know if the reagents are still fine anymore.

HereFishyFishy, Eric said that skimmers don't truly Oxygenate the water. You needed to have a fuge lit off-cycle to do that. I cannot comment. I did have a fuge at the time I did my test but didn't light it off-cycle.

I can say this...if you have a nano with a sandbed, power-loss equals major losses in DO. But that's the extent that I can comment.

 

[steve-s]

I know that one way to see if your water might be poorly oxygenated is to test the pH of the water before and after heavily oxygenating it by putting a gallon or so in a bucket with a powerhead for a couple hours. But the chem experts would have to say more about that, because I don't know the details of that method.

pH is controlled by CO2, not O2. You can saturate water with all the O2 you want but if it has too much CO2, the pH won't budge.

 

[DonW]

Oh, PULLEEZE!!! Anyone who has known you for some time knows that, not only have you've built a robot to test for DO, you have another one programmed to make modifications, and a third one just to make sure the first robot was right.

Very funny. But now that you mention it, the redox potential of pure oxygen is pretty high. So would we be altering and controlling DO with O3?

Don

 

[Herefishyfishy]

HereFishyFishy, Eric said that skimmers don't truly Oxygenate the water. You needed to have a fuge lit off-cycle to do that. I cannot comment. I did have a fuge at the time I did my test but didn't light it off-cycle.

Hmmm, Does not the aeration present in the skimmer add dissolved gasses into the water? I do understand the law of partial pressures and realize if the O2 level in the air is low, that the dissolved O2 would also be low, but have a hard time not accepting that gas exchange would occur in a skimmer if it occurs in the waterfall of overflows, etc. Did he test with skimmer on and off and the results showed no difference? Perhaps the oxygen was already functionally saturated. Quite interesting. Got my curiosity up, will have to google for any test results.

I also run my fuge off cycle to balance PH.

First find, incomplete but interesting:
http://www.aquarticles.com/articles/management/Llambi_Water5.html

 

[DonW]

Hmmm, Does not the aeration present in the skimmer add dissolved gasses into the water? I do understand the law of partial pressures and realize if the O2 level in the air is low, that the dissolved O2 would also be low, but have a hard time not accepting that gas exchange would occur in a skimmer if it occurs in the waterfall of overflows, etc. Did he test with skimmer on and off and the results showed no difference? Perhaps the oxygen was already functionally saturated. Quite interesting. Got my curiosity up, will have to google for any test results.

I also run my fuge off cycle to balance PH.

First find, incomplete but interesting:
http://www.aquarticles.com/articles/management/Llambi_Water5.html

The skimmer is more productive at getting rid of the co2 leaving more room for 02 was more my understanding. Heck sound good to me.

Don

 

[Herefishyfishy]

Don, I like the way you think LOLOL
Skimmer also gets rid of waste which improves the Redux (as understood by this cretin)
Here is what Tyree has to say:
http://www.ecosystemaquarium.com/html/tyree1.html

 

[Curtswearing]

Very funny. But now that you mention it, the redox potential of pure oxygen is pretty high. So would we be altering and controlling DO with O3?

Don

I don't think so but I would love Boomer's comments. O3 is HIGHLY unstable from the "get-go" and that's where the Oxidation comes from. Remember, at the air/water interface there is a lot of fun things happening.

Hmmm, Does not the aeration present in the skimmer add dissolved gasses into the water? I do understand the law of partial pressures and realize if the O2 level in the air is low, that the dissolved O2 would also be low, but have a hard time not accepting that gas exchange would occur in a skimmer if it occurs in the waterfall of overflows, etc. Did he test with skimmer on and off and the results showed no difference? Perhaps the oxygen was already functionally saturated. Quite interesting. Got my curiosity up, will have to google for any test results.

I was there as well as two other RF members. I'm only stating what was said, not what I believe. CO2/O2/pH issues have been discussed at length here in numerous threads. In fact, there are several very easy tests that you can perform to determine if your pH problems are due to excessive CO2. The methods he used to explain his statements were not described.

 

[DonW]

I don't think so but I would love Boomer's comments. O3 is HIGHLY unstable from the "get-go" and that's where the Oxidation comes from. Remember, at the air/water interface there is a lot of fun things happening.

It being unstable also makes it easy to loose the third molecule thus leaving o2 correct? If you were to make some sort of pressurized canister (oxygen reactor) and inject pure 02 into it, the orp would also go way up. I think A. Theil sp? has a article some where on oxy reactors, orp and using them to increase DO.

Don

 

[Herefishyfishy]

Curt, I appreciate you forwarding what you heard. Just a point of curiosity to me is all. Starting to Look like the entire air pump/air stone industry was based on false info. Never accepted they did much, even the lime wood ones. But a huge skimmer with high flow and a lot of turbulence sure seems to create a lot of water/air interaction which should illicit gas exchange?

Anyway, thanks for the update, will be interesting to see what Eric has to say. As to the night lighting of the plants, it just seemed a logical time to run the fuge. PH is fine. I miss my Moonlights though, sniff. They were on the same timer as the fuge. Was told they are bad for the corals

Regards to all and hope none were offended by my opins (I have a tendency to do that).

 

[sihaya]

pH is controlled by CO2, not O2. You can saturate water with all the O2 you want but if it has too much CO2, the pH won't budge.

Right, right, of course... I didn't really mean "oxygenation." I meant "airation." The two are kinda related though, right? If your water isn't airated properly, CO2 will build up and you won't have enough oxygen.

 

[Scooterman]

Thought I'd post some photos of aeration, & oxygenation!

 

[Curtswearing]

The only time I worry about it is when my tank hits 88 degrees in the summertime and during the wintertime when there's little fresh air coming in and my ph won't rise above 8

Robert,

Your point is good. As temperatures increase (all else being equal), dissolved Oxygen does decrease. There's a chart in my first link that discusses this fact.

The Need to Breathe in Reef Tanks: Is it a Given Right?


Here are the remaining two articles in the series. Interestingly enough, what he discussed in the meeting goes 100% against his own research. Check out the graphs on this next link.

The Need to Breathe, Part 2: Experimental Tanks


The Need to Breathe, Part 3: Real Tanks and Real Importance

 

[sihaya]

Here are the remaining two articles in the series. Interestingly enough, what he discussed in the meeting goes 100% against his own research.

Are you talking about the streaming video of the lecture on the IMAC site? Because yeah, I too wondered about some of the ways he was interpreting the data. I kinda took a lot of what he said on faith (which I don't usually do). But what he was saying made sense I guess, so I didn't think about it too hard. I should have though.

Anyway... the idea that oxygen decreases with increased temperature is certainly not new. That's been known for ages. What I'd like to know/understand is why the oxygen levels fall so much at night in tanks but not in the open ocean. In other words, this chart interests me:



Of course, I'm disappointed by the five hours of missing data. Who needs to sleep anyway? lol j/k