Dissolved oxygen, saturation, supersaturation

Mei · Post by **Mei** » 20 Dec 2006, 08:03

I have recently set-up an oxygen cylinder (+ regulator and flowmeter) and micro-bubble diffuser (don't worry, the diffuser has not been set to a dangerous rate). It is currently off but I did run it for a few hours and registered a minor change in DO value. Mind you, I am not too confident in these O2 test kits and will be buying a DO meter shortly.

I am interested in learning the advantages and disadvantages of using oxygen gas to enable an optimum DO level (both for fish-keeping and for interest's sake).

Does anyone have any experiences with this? And if I am not using additional pressure (i.e. injecting o2 under pressure), am I still able to supersaturate the tank water?

Thanks,

Mei.

MatsP · Post by **MatsP** » 20 Dec 2006, 12:23

I don't think you'll achieve supersaturation unless you use high pressure to inject the gas.

I'm also almost convinced that it's completely unneccessary to use O2 gas in such a system, as normal air contains just under 20% O2, and as long as you have sufficient motion of the water, you'll achieve good DO values.

--
Mats

Post by **Shane** » 20 Dec 2006, 17:53

You might find this article useful.

http://www.planetcatfish.com/shanesworl ... cle_id=313

O2 saturation is mainly controlled by temperature and the water's chemical composition. At 90F the water is saturated at 7.4 mg/L and at 45F 11.9 mg/L. I guess the main point is that even a slight drop in temp (but still in a range the fish are happy in) will increase your O2 levels more than anything else you could do. With few exceptions, many "tropical" fishes are fine anywhere between 74-76F and can be kept at those temps instead of the 80-82F that is common.
-Shane

grokefish · Post by **grokefish** » 20 Dec 2006, 18:56

I have developed a fab way of oxygenating the tank water without any surface agitation for my big tank an my living room.
It's really quiet and it delivers the oxygenated water where it is needed (at the bottom) without the noise of an airpump or trickling water.

fakiren · Post by **fakiren** » 21 Dec 2006, 00:23

grokefish wrote:I have developed a fab way of oxygenating the tank water without any surface agitation for my big tank an my living room.
It's really quiet and it delivers the oxygenated water where it is needed (at the bottom) without the noise of an airpump or trickling water.

Witch is?

MatsP · Post by **MatsP** » 21 Dec 2006, 12:16

Matt, when your patent application is through, can you please let us know where we can buy the product?

Or if you're not keeping it a secret, tell us now...

--
Mats

synodontis · Post by **synodontis** » 21 Dec 2006, 22:43

dissolved oxygen meters are worthless, you might as well stick a thumb in the tank and measure the oxygen levels that way!!

You can achieve oxygen saturation by having a thriving planted aquarium, and what happens is at the peak the plants will start "blubbling", the only drawback is your stocking levels have to be low, and you can't keep boisterous/clumsy/large fish since they will ruin the setup

There are other ways of oxygen saturation, like using a pressurised oxygen reactor and/or pressuried trickle tower. But I would conjecture such levels will be seriously short lived.

Lastly, and I am deadly serious about this, anyone trying to supersaturation their tank will oxygen has to have something wrong with them. It does not really happen in nature, and I take it as fishkeepers we are here to consider the safety and comfort of our fish. We are not running an intensive fish farm. Having a highly oxygen saturated tank is not a good excuse to increase stocking levels.

racoll · Post by **racoll** » 22 Dec 2006, 09:44

You can achieve oxygen saturation by having a thriving planted aquarium, and what happens is at the peak the plants will start "blubbling"

The problem with this is that you will only get oxygen released in the daytime. At night the plants will consume oxygen.

As a result the oxygen and pH levels can fluctuate over a day/night cycle.

A solution to this may be a refugium/sump as used in the marine hobby.

Have the sump setup on a reverse photoperiod with some fast growing stem plants, and in theory the system should balance.

I find myself that I achieve "sufficient" oxygenation with powerheads and airstones, but until someone tries adding supplementary oxygen we may never know if it brings any benefits.

.

Bas Pels · Post by **Bas Pels** » 22 Dec 2006, 10:54

synodontis wrote: Lastly, and I am deadly serious about this, anyone trying to supersaturation their tank will oxygen has to have something wrong with them. It does not really happen in nature, and I take it as fishkeepers we are here to consider the safety and comfort of our fish. We are not running an intensive fish farm. Having a highly oxygen saturated tank is not a good excuse to increase stocking levels.

I do think this is the hammer on the nail: does it happen in nature? if not, another solution ought te be found.

In this case, less fish, more water movement, lower waterlevel, more waterchanges. In January I collected Rhinelericaria in 5 cm water, over rocks, moving with over 1 meter a minute. I'm certain it was cleaner than my tapwater.

As long as your circumstances are not this extreme, room for improvement still excists.

Luckely these fish also thrive (I have young ones) in 40 cm water, over sand, moving with approx 3 meters an hour

butterfly · Post by **butterfly** » 22 Dec 2006, 13:28

Mei wrote: I am interested in learning the advantages and disadvantages of using oxygen gas to enable an optimum DO level (both for fish-keeping and for interest's sake).

Mei I see your objective stated but I don't see what kind of fish( sorry if I missed it somewhere) your trying to keep under these conditions and does it come from a highly oxygenated environment.
I keep Hillstream Loaches( I know their not catfish) that have to have cooler water(more oxygen), currrent(more oxygen ?) and extremely clean water so this interests me.
Is there a danger to the health of certain fish with supersaturation of oxygen?
Carol

grokefish · Post by **grokefish** » 24 Dec 2006, 19:57

Sorry I forgot I had posted that one.
Anyhoo i wanted to have suitable oxygen levels in my tank which is 24" deep without too much surface movement or any if I could get away with it.
This tank is in a very quiet room and I wanted to keep it that way, a really good chill out room. So I worked on the pricipal that if oxygen exchange occurs at the surface then transporting the well oxygenated water from the thin layer at the surface to the lower reaches of the tank would be a more efficient idea than bringing the less oxygenated water to the surface.
I don't know if this is an original idea or not but this is how I did it.
I pulled out my big box of aquarium crap and dug out an old power head and a surface skimmer that I had been using on a planted tank that is now in storage and simply connected them.
See
[img][img]http://img1.putfile.com/thumb/12/35714415691.jpg[/img]

Ah but there is airlines I can see them you cry!
Well I'm just testing this system out for now so I've got an airpump rigged up if they start gasping but so far so good.
An added bonus is that it skimms the protien off the surface and mixes it back into the water column to go into the filter giving a loverly clear surface.
Ta Da!
I don't think it is any good for rheophilic fish but for the likes of dorads woodcats (Not trachycorystes that in my experience likes a good bit o oxygen) corys and the other fish including royal panaque, glyptoperichthys and pseudorinelepis or however you spell it. I have in there it seems fine. So far no gasping uarus and the cory's very rarerly zoom to the surface for air, no more than I have seen them do so in other tanks and I have been watching the tank from the sofa for the last 36 hours nursing a terrible hangover from getting engaged to Kath on friday.
What do you think guys?

Dissolved oxygen, saturation, supersaturation

Dissolved oxygen, saturation, supersaturation

Re: Dissolved oxygen, saturation, supersaturation