O2 level
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Miami Reef
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I don’t. I think it’s pointless. Surface agitation is all you need.
HuduVudu
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Oxygen makes up a huge percentage of our atmosphere, and is not depleted rapidly. Oxygen is rarely an issue in salt water aquariums.
IMO the most important atmospheric gas is CO2. It is more important to your aquarium than oxygen because it impacts many systems. When gas exchange is discussed this is the primary gas that is referred to.
It is a bit hard to find, but Salifert does have a test. It doesn't really provide useful gradients but unless you are really willing to kick down some cash this is the best you will get.
Here, if you want to spend money:
Dissolved Oxygen Test Kit
This kit tests for Dissolved Oxygen using the Direct Reading Titrator method. Range/sensitivity is 0-10 ppm/0.2 ppm O2.
lamotte.com
blaxsun
10K Club member
If you had an ORP probe running 24/7 you might feel differently. I can immediately tell whenever I add certain supplements or something is off in the tank.
It's not mission critical - but it does give you another piece of the puzzle.
Personally I think Oxygen is an important issue and may fish benefit from a higher level.of O2 than with just surface agitation in a tank.
Miami Reef
10K Club Member
I don’t think so. ORP is extremely complicated and the benefits are not cut and clear.
DaJMasta
Well-Known Member
Worth mentioning that ORP is not dissolved oxygen (DO), though DO does influence ORP.
Salifert makes a test kit, and DO probes and meters are used for water analysis fairly routinely for a lot of aquatic applications. I know studies have been done measuring DO in a reef tank (water column vs high in the substrate vs deep in the substrate) and over time, but I don't know of anyone who regularly monitors it.
The only real application I can think of, and the only time I've bothered, is to measure when medicating a tank (say, with azithromycin), but odds are good normal circulation will keep the DO level pretty stable. Unlike CO2, it doesn't seem to be as dependent on ambient oxygen content - probably because the maximum DO in saltwater is relatively low, so it doesn't take a huge amount in the atmosphere around a tank to fully saturate it.
Salifert makes a test kit, and DO probes and meters are used for water analysis fairly routinely for a lot of aquatic applications. I know studies have been done measuring DO in a reef tank (water column vs high in the substrate vs deep in the substrate) and over time, but I don't know of anyone who regularly monitors it.
The only real application I can think of, and the only time I've bothered, is to measure when medicating a tank (say, with azithromycin), but odds are good normal circulation will keep the DO level pretty stable. Unlike CO2, it doesn't seem to be as dependent on ambient oxygen content - probably because the maximum DO in saltwater is relatively low, so it doesn't take a huge amount in the atmosphere around a tank to fully saturate it.
You think that’s O2 or CO2 though? I think bacterial populations can change at at different pH levels, which could possibly affect all sorts of things. Not sure if Oxygen has the same effect unless you get a bacterial bloom, stealing all the oxygen.
Am saying certain things need more oxygen than many tanks provide. Take Achilles tangs as one example. They come from areas of the reef with over 100% oxygen saturation.
I did a little poking around after reading @Jay Hemdal s. Gas Bubble Disease article a while ago and it appears large algae beds can indeed supersaturate to over 100% however, I’m not sure that applies when there’s a million litres of water passing over the area. Seem to remember 110 to 120% was problematic. Excess aeration would reduce supersaturation, not increase it, as it normalizes with air.
O2 is not very soluble in water and even.less so in salt water unlike CO3. Many parts of the reef are super saturated in O2 which is hard to achieve in our tanks without some major intervention. Add to that few monitor O2 levels and IME hobby test kits are pretty poor at giving accurate results and it becomes an unknown level in our tanks. So how dose that impact on our tanks? Well some fish wont6do as well or feel comfortable in less than ideal 02 some do this by not showing their true vibrancy or energy and some will show signs if stress perhaps even being more susceptible to disease and parasites.
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And also introduce more CO2 if the room was high in it. On the reef cressed without algae beds O2 also rashes super saturation as the waves batter it. Low O2 together with.high CO2 is IMO dangerous and wearing to our fish
From a series in 3 parts bye Eric Borneman.
Quote "Airstones and skimmers appear to be a very effective means of oxygenating small water volumes. Their effect on larger water volumes appears to be less. While the effect may be relative, the larger tanks and systems described here utilized powerful skimming or air pumps, and to gain an equivalent amount of oxygen as occurs in small water volumes would likely require air pumps or skimmers far larger than those commonly employed by aquarists. This includes data from a coral farm where very large commercial sized skimmers and high surface area/volume ratios failed to produce water even nearly saturated with oxygen at night with a heavy coral population.
Powerheads and recirculating pumps do not appear to greatly increase the oxygen saturation state of seawater aquaria. Instead, they probably serve to move oxygenated waters to areas of the tank that are locally lower in oxygen resulting from respiration within the tank."
Quote "Airstones and skimmers appear to be a very effective means of oxygenating small water volumes. Their effect on larger water volumes appears to be less. While the effect may be relative, the larger tanks and systems described here utilized powerful skimming or air pumps, and to gain an equivalent amount of oxygen as occurs in small water volumes would likely require air pumps or skimmers far larger than those commonly employed by aquarists. This includes data from a coral farm where very large commercial sized skimmers and high surface area/volume ratios failed to produce water even nearly saturated with oxygen at night with a heavy coral population.
Powerheads and recirculating pumps do not appear to greatly increase the oxygen saturation state of seawater aquaria. Instead, they probably serve to move oxygenated waters to areas of the tank that are locally lower in oxygen resulting from respiration within the tank."
Jay Hemdal
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Accurately measuring DO has always been a challenge for me. Many years ago I used the Chemetrics photometer that worked quite well, but it cost to much to run ($1 per test). I then used various Hanna multiparameter probes - the trouble with those is that they require membrane replacement very frequently, and really, their results could only be used to see trends over time. DO optical sensors are supposed to be the best, but too expensive for me.....but the cost has come down a bit. YSI has one for $1600 now.
Jay
DaJMasta
Well-Known Member
I've used a couple of YSI DO meters (one multiparameter, one just DO) and the membranes were rated for 4-8 weeks, but the primary degradation they saw is slowness to respond while measuring, so an in-place monitor or just longer sample times may give you some usable lifetime beyond that. I know the membrane on my 556 is quite a bit older, but gives reasonable sounding readings after a couple minutes of immersion.
If you're looking at the optical route, basically you need an oxygen sensitive patch that lives on the inside surface of the aquarium, then an excitation source (a blue LED of known properties) and an optical spectrometer. Complete systems are pricey, and the patches themselves are $40+ each, but the patches have a very long lifetime and almost any source/spectrometer can do. Case in point, I got an old Instech Labs dissolved oxygen meter for cheap in unknown condition, on disassembly, it was just an Ocean Optics S2000 spectrometer and a 450nm blue LED source and a standard fiber optic reflectance probe. When powered up, the blue LED lights and a sample is taken, and the whole thing interfaces over USB to standard Ocean Optics software.
Now getting a calibrated reading of an absolute measurement probably involves some reference spectra and a performance curve for the patch being used, but the dry side hardware to get a consistent reading is probably much simpler than the pricetag suggests, and older scientific grade fiber spectrometers are a heck of a lot cheaper than $1600.
If you're looking at the optical route, basically you need an oxygen sensitive patch that lives on the inside surface of the aquarium, then an excitation source (a blue LED of known properties) and an optical spectrometer. Complete systems are pricey, and the patches themselves are $40+ each, but the patches have a very long lifetime and almost any source/spectrometer can do. Case in point, I got an old Instech Labs dissolved oxygen meter for cheap in unknown condition, on disassembly, it was just an Ocean Optics S2000 spectrometer and a 450nm blue LED source and a standard fiber optic reflectance probe. When powered up, the blue LED lights and a sample is taken, and the whole thing interfaces over USB to standard Ocean Optics software.
Now getting a calibrated reading of an absolute measurement probably involves some reference spectra and a performance curve for the patch being used, but the dry side hardware to get a consistent reading is probably much simpler than the pricetag suggests, and older scientific grade fiber spectrometers are a heck of a lot cheaper than $1600.
Malcontent
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Replacement sensors for my probe went from $95 for $156 so I looked around to see if any other manufacturers had sensors that looked similar but were cheaper (e.g., rebadge jobs) but no such luck.
I did come across what is the cheapest optical dissolved oxygen meter I've seen so far. It requires an interface which is as little as $70. There's also a wireless version that doesn't require one.
The sensor looks similar to the YSI ones at half the price so if I had a YSI probe I might be tempted.
Most basic YSI ODO setup is $1017. But it's very, very basic.
I did come across what is the cheapest optical dissolved oxygen meter I've seen so far. It requires an interface which is as little as $70. There's also a wireless version that doesn't require one.
The sensor looks similar to the YSI ones at half the price so if I had a YSI probe I might be tempted.
Most basic YSI ODO setup is $1017. But it's very, very basic.
aquatimeFL
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I would like to comment in a constructive way on this topic. I have been researching this data for years now and I have tested all the most common methods of oxygenation that aquarists use. I hate to tell people this who believe only in surface agitation, but by far surface agitation is the worst at oxygenating aquariums out of all methods. People don't realize how under oxygenated their tanks are when they don't actually test dissolved oxygen. Or understand the science in dissolved oxygen. Thats why one of the most important things water treatment plants do all throughout the cleaning process of our drinking water is oxygenate, oxygenate and of course oxygenate more. It increases good bacteria which helps clean our drinking water. In the fish farming industry, you will never see any operation just using water surface movement. If they do it's because they are using huge wavemakers chopping up the surface like a blender. Fish and aquatic life need as high of natural dissolved oxygen as possible for healthy water and to grow. Most people don't realize their aquariums at home are on the very depleted end of that and their fish are slow and lazy and corals and plants grow very slow and constantly get diseases.
Tests:
8-9 mg/L of O2 is what is considered optimal for aquatic life outside of aquariums in colder waters. Cold waters hold more dissolved oxygen.
All tests were done in the test aquariums at night when the oxygen consumption is at its highest and plants are not producing oxygen, but consuming it.
Water temp :26 Celsius...... the dissolved oxygen saturation point of water at 26C is 8 mg/L
surface agitation and wavemakers 5.8mg/L of O2. that's really low and most fish gasp for air.
single large output air stone 6.8mg/L of O2. that's decent and fish will stop gasping for air
Multi Venturi injector 7.9mg/L of O2. that's nearly the saturation point of water at that temp.
Once you get dissolved oxygen that high near saturation point the benefits are tremendous. Water never becomes cloudy because the good bacteria gets the oxygen it needs to really speed up the nitrogen cycle. Good bacteria needs oxygen just like fish, corals, plants and everything else competing in your tanks for it. The amount of water changes you need drastically reduce because the good bacteria is firing on all cylinders. Fish visibly have much more energy and reproduce much more often. Plant and coral growth explodes. There are countless benefits.
Surface agitation just doesn't do much unless you are getting quite a big splashing effect. If you are just getting ripples then yes, its keeping your fish, corals and plants from all dying. However, they are just 1 - 1.5 mg/L of O2 away from dying. So Its not a very healthy environment. Get some Aeration in your Aquariums other than wavemakers and nozzles and you will be blown away at the changes you will see. I recommend a multi-Venturi because it can be placed in a sump before a bubble trap and you wont get any bubbles or microbubbles in your aquariums. The pressures and bubble collisions inside of the device are what help dissolve oxygen faster than a traditional air stone. A multi-venturi connected to just a 350GPH water pump can suction in 4 - 5 L/min of air. That's quite a large volume of air
I hope this at least makes those who believe in only surface agitation to consider trying something new and test their dissolved Oxygen. their fish, plants and corals will thank them.
Happy Aerating!
At last somebody who agrees with me. Even a skimmer won't do as much as is needed to bring oxygen to optimum levels in fact it may well introductory more CO2 than O2.
On the reef oxygen can reach super saturation levels, over 100%. I don't profess to know all the science behind it but I read a scientific paper some years ago that showed the oxygen levels on a healthy reef showing high levels of O2.
You may or may not know I am a big advocate Oxydators which I have been using in my reef tanks for over 30 years. When I first started experimenting with them I noticed increased vitality and colour in my fish they also seemed healthier and the likes of white spot became a thing of the past. I don't attribute all this to just my Oxydator's but also how I keep my reef tank in general. However, I have nodoubt my Oxydators play an important part in the health if my fish.
Randy Holmes-Farley
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I’d really like to see a lot more O2 measurements of reef tanks, but it is expensive and few do it. Kits are not suitable, IMO.
[note: I edited this as I mean to say that kits are not suitable]
[note: I edited this as I mean to say that kits are not suitable]
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