Dissolved Oxygen

[ReeferDave01]

Neptune Systems Apex sells Dissolved Oxygen sensor. How many of you use that & do you find it useful? Do you aerate your tanks? Do you find the need for that? I have been aerating my tank at night within the sump but not sure if that's beneficial or not.

 

[Reefing Madness]

Are you doing it to keep your PH level across day and night periods?

 

[ReeferDave01]

Yes I started aerating to increase pH. My pH has been 7.7-7.8. Adding aeration Ive seen it go up to 7.9 at peak which was still not good. Last week I added O2 Scrubber without aeration, and now it's been averaging 8.0 with a swing either way only 0.05 day/night. I'm traveling extensively next 2 weeks, but when I'm back home, I'll run aeration again & see if that makes a difference and bumps it more to 8.1 where I want to be.

 

[Reefing Madness]

So you have your power heads pointed at the surface of the tank water? Is there a ripple there? Do you have lids on your tank?

 

[ReeferDave01]

I'm using 2 maxspect gyres on each end of tank which I love. I have 4 inlet nozzles moving surface of tank. I have couple powerheads which I haven't installed yet that will eventually point upward. I have lid because I'm using marine orbit pro led which sits low to the tank and 4 bulb t5 lights all 72 inch

 

[Reefing Madness]

AH, thus the reason you have to aerate, the lid.

 

[Ranjib]

I just stumbled upon this. I am working on supporting DO probe in reef-pi, and very curious about what all use cases it solves. I am doing the integration due to some other reason (some students are using it to analyze brackish ecosystem), but I had this exact question, what are the relevant usage of DO probes in reef hobby. Is it just the O2 level that in turn impacts pH (which seems to be more related to CO2 level) or there are more to this..

 

[ca1ore]

The apex PM3/DO kit is about the only module I don’t have. The probe is very expensive and requires frequent membrane replacements. Since a well designed and run tank approaches oxygen saturation, the cost never seemed worth it. FWIW, aerating the sump seems singularly pointless to me. I think many fail to understand how a bubbler affects oxygen, so unless you are running a stagnant sump, pointless.

 

[Scrubber_steve]

Yes I started aerating to increase pH. My pH has been 7.7-7.8. Adding aeration Ive seen it go up to 7.9 at peak which was still not good. Last week I added O2 Scrubber without aeration, and now it's been averaging 8.0 with a swing either way only 0.05 day/night. I'm traveling extensively next 2 weeks, but when I'm back home, I'll run aeration again & see if that makes a difference and bumps it more to 8.1 where I want to be.

a study by Borneman showed that using pumps to increase the oxygen content doesn't work. An air pump & skimming is ok if the air supply is fresh, & photosynthesis is best.

The Need to Breathe, Part 2: Experimental Tanks

 

[eag]

I always read about aeration, how to improve gas exchange, etc... sometimes, I really wonder about it... If I have to dose meds, and turn off my skimmer for a while... does my setup provide enough exchange? How much does the skimmer affect O2 levels. If it's off, how bad is it?

What about bacterial bloom? They say the bacteria will quickly deplete O2... but if the bloom isn't too bad... do I need an aerator? What exactly is the impact, and specifically, on my system?

I have chronically low pH... I know that if I aerate the water outside, it improves. But what is it really? Is it that my apartment is poorly ventilated, and the interior air has a high CO2 concentration? Or is it poor gas exchange? Or maybe both?

I sometimes see my fish stove piping - sucking in air from the surface. I suspect it is gill fluke... but prazi didn't zap it as expected. Do I need more prazi rounds? Why is it that not all the fish do this? Could it be O2 and not flukes at all? Who knows...

In the end, if you want to answer these questions... you really want a number... so, I guess it's an expensive number... but it answers questions and brings insight. Call me a sucker, but I like numbers and I like answers now if I can only get it to work...

 

[CEReefer]

Ph is not affected by O2, only CO2 affects pH (CO2 + H2O <> H2CO3 the latter being carbonic acid, then H2CO3 <> H+ + HCO3) therefore increases the concentration of hydrogen ions dropping pH.

O2 concentration is affected by temperature, and salinity raising temperature will decrease the capacity of the water to keep oxygen (and for that matter CO2 too) in solution, same for salinity.