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With Plecos that your keeping at higher then "typical" fish temperatures like L-333 or L-046. What methods do you use to increase oxygen saturation? In alot of the photos posted, I havent noticed a spraybar in the back of the tanks. So Im assuming, the prefered method is to have a power head in the upper column of the tank to increase surface agitation?

Hi all,
At 24.0oC, at mean sea level and 1013mb pressure, pure water (H2O) is saturated with 8.3mg/l O2. At 34.0oC with only 7.0mg/l O2, so yes temperature is important.

You can ignore the effects of added solutes (what we call water is rarely H2O, and usually a dilute solution) which reduce the total amount of DO, but atmospheric pressure is also relevant, particularly if you live in Denver, (multiply all values for dissolved O2 (DO) by 0.83 if you do). It is also worth noting that this pressure effect will also occur at low altitude during periods of abnormally low barometric pressure.

Having said that aeration is quite a complex subject, and my suggestion would be to read this article, written with Loricariid keepers in mind:

"Aeration and dissolved oxygen in the aquarium" here: <http://plecoplanet.com/?page_id=829>.

This breaks all of the processes, that contribute to oxygenation and de-oxygenation, down into their constituent parts, and suggests practical techniques for ensuring oxygenation in your aquaria.

cheers Darrel

There is also a guide here on Planet Catfish:
http://www.planetcatfish.com/shanesworl ... ved+oxygen

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Mats

That was a good read. Thank you.

dw1305 wrote:Hi all,
At 24.0oC, at mean sea level and 1013mb pressure, pure water (H2O) is saturated with 8.3mg/l O2. At 34.0oC with only 7.0mg/l O2, so yes temperature is important.

You can ignore the effects of added solutes (what we call water is rarely H2O, and usually a dilute solution) which reduce the total amount of DO, but atmospheric pressure is also relevant, particularly if you live in Denver, (multiply all values for dissolved O2 (DO) by 0.83 if you do). It is also worth noting that this pressure effect will also occur at low altitude during periods of abnormally low barometric pressure.

Having said that aeration is quite a complex subject, and my suggestion would be to read this article, written with Loricariid keepers in mind:

"Aeration and dissolved oxygen in the aquarium" here: <http://plecoplanet.com/?page_id=829>.

This breaks all of the processes, that contribute to oxygenation and de-oxygenation, down into their constituent parts, and suggests practical techniques for ensuring oxygenation in your aquaria.

cheers Darrel

ThinkI have 6-8mg/l using the API test kit, all I have is the fluval U4 with airline to produce bubbles and current, the eheim 2073 external spray bar near the top

Going to add the Eheim 400 air pump with 2x difusers to see if i can create a bit more before adding a powerhead, only as in my L46 tank I also have shrimp and cardinals

is 6-8 mg/l acceptable in a tank which has 84 degrees temp?

I now run Hydor Koralia powerheads in all my tank to agitate the surface, whether they are CO2 injected or not. Reduces surface film and minimizes splashing noise. When adjusted properly, a nice "boiling" effect can be achieved, which can greatly increase the size of the air/water interface, but minimize splashing. In my bigger tanks I do this with a combination of powerheads and filter spraybars/outlets.

Is it better to agitate the water surface with a power head or use an airstone?

There are arguments for both. I don't like the 7up look in my tanks and don't like the noise so I use powerheads - no venturi.

The benefit of an airstone is:
1. It introduces new air into the (usually) enclosed tank system.
2. It lifts water from the bottom of the tank up to the surface, where contact with the air oxygenates the water.

--
Mats

Hi all,

There is also a guide here on Planet Catfish: http://www.planetcatfish.com/shanesworl ... ved+oxygen

There is absolutely nothing wrong with Shane's article. I only referred to "Aeration and dissolved oxygen in the aquarium" <http://plecoplanet.com/?page_id=829>, which covers much the same ground, because of its greater detail.

I wrote the "Aeration....." article following working with lab scale models (and an extant commercial scale treatment works) of the practical techniques in the biological re-mediation of "landfill leachate", which you can think of as uber polluted tank water, with a very high biochemical oxygen demand (BOD).

In terms of physical aeration it is mainly down to 3 factors, flow speed, the size (and residence time) of the air bubbles in the water column and the "surface area to volume" ratio of the tank.

Without going into the full details, you want:
Fast linear flow, very small bubbles (in the range of 10 – 200 microns diameter and with a long residence time) and a large surface area to volume ratio, so a wide, shallow tank.

Having said that, in some ways these are the least relevant factors, the really important bit is to have actively photosynthesising plants (to fully saturate the water with O2 and preferentially remove ammonia during the day) and extremely efficient biological filtration.

Because biological filtration is an oxygen intensive process "extremely efficient biological filtration" really means either a planted sump with reversed light regime or a "wet and dry" trickle filter, or even better 2 planted wet and dry trickle filter with reversed lighting regimes, but relatively few freshwater aquarists will go down that route.

cheers Darrel

Hi all,

is 6-8 mg/l acceptable in a tank which has 84 degrees temp?

This is pretty near 100% saturation. What you need to remember is that you can have excellent oxygenation values for 99.9% of the time, but if the dissolved O2 level is lethal for that 0.1% of the time, you have killed all your fish. This is a common one with planted tank enthusiasts who use CO2 (I'm a planted tank enthusiast, but I don't use CO2), a CO2 dump into a tank, even if fully saturated with O2, will kill the fish due to the Bohr effect.

Professional freshwater biologists usually use both a biotic index and "5 day BOD" to estimate water quality, as these are a "better" measure than DO or NH3 monitoring (unless it is continual). Unfortunately neither method is possible for the aquarist.

cheers Darrel

All a bit technical is my current oxygenation good or bad?

Neo wrote:All a bit technical is my current oxygenation good or bad?

Sounds like it's good, because it's near the maximum you can get. Caveat: home O2 measurement kits are not very accurate, because you have to mix the reagent with the water, which increases the O2 level if it was low to begin with. Electronic meter is much better, but costs A LOT of money.

Not saying this is by any means a good place to buy, it's just the first proper page I found in google:
http://www.thepondreport.com/aeration-o ... sfer.shtml

$190-$400 is quite a bit, tho'.

In the UK, Hanna Instruments makes good stuff, but their "Budget Portable DO meter" is £426... ;)

--
Mats

Hi all,
We've got a variety of DO meters in the lab. the Hanna one is very good for the money.

To be honest, no home kits are going to give you more than a ball park figure. Unless you are both wealthy and have a lot of time, the only meter (or test kit) that is worth investing in is a reasonable quality low range conductivity meter.

I use rain water, because we get a lot of rain and it is "ethical" but if I didn't have these resources/qualms the first bit of kit I would get would be a RO unit. I have access to unlimited amounts of deionised water, but I don't use it unless we've run out of rain water.

Some of my tanks are actually in the lab, where lab. quality analytical kit including HPLC, AAS etc is permanently set up and maintained, but I very rarely use it for the tanks and it still wouldn't tell me anything that I can't see from the growth of the plants and activity of the fish.

cheers Darrel

Im adding in an eheim 3704 with x2 difusers to see if i can get my levels up with the kit i do have, failing that I may add a power head but with the external spray bar and the u4 internal I dont want to create too much turbulance as I also have cardinals and shrimps in my tank

Just want to keep my fish happy and healthy

The benefit of an airstone is:
1. It introduces new air into the (usually) enclosed tank system.
2. It lifts water from the bottom of the tank up to the surface, where contact with the air oxygenates the water.

Perhaps most importantly, airstones add water movement (and thus O2) without adding heat. A power head will also increase surface agitation (and thus O2) but will at the same time lower O2 levels because the submersed motor that runs it will heat the tank. I have seen some newer power heads that attempt to conquer this problem by keeping the motor out of the water.

Above is not a major issue for loricariid breeders "cooking" their fish into spawning (a subject that has been well studied in aquaculture), but an issue for hillstream and piedmont fishes that need high O2 levels but can not tolerate high temperatures.

I have tried to research the long term impact of cooking, but there is little data as the studies involve mainly food fishes and thus terminate at the point the fish are raised to market size. Don't get me wrong, treating H. zebra (and many other loricariids) like you were aquaculturing Tilapia (frequent massive feedings, higher than natural temps, etc) will result in your fish reaching breeding age faster, reproducing more frequently, and producing larger spawns. This has been proven by both hobbyists and a body of scientific literature.

-Shane

I don't know what the temps are in PA, but my Hypan tanks still require heaters in the middle of summer where I live, so the heat given off by my powerheads don't come into play. In my planted tanks, the lights account for way more heat than the powerheads, and interestingly enough, and logically, my UV sterilizers add way more heat to the tank.

But you're right Shane, that airstones don't do add heat.

I think though, the most efficient would be a wet/dry. Heat would be shed (unless you're trying to heat it), and the water/air interface would be maximized.

Okay, here are my 2c on keeping the fishes mentioned by the OP (i.e., ). You won't need to go to the effort of using really inaccurate oxygen test kits if you consider the following:

Get a wide rather than tall tank (maximises surface area to volume ratio).

Use an airstone to introduce clean air into the system if your tank has a hood and condensation tray.

Let powerheads/pumps do the majority of the work of moving water around. Good turnover is required, but you won't need a boiling cauldron. Many of the new reef pumps can move large quantities of water in a diffuse "beam" that doesn't take your skin off.

Reduce organic waste in the tank as much as possible--valuable oxygen is consumed as the waste is broken down. This means keeping the filter clean, and not using gravel, which traps detritus and uneaten food (always use a thin layer of sand, or ideally a blend of sand, fine gravel and larger gravel). Don't use much or any bogwood, as this will also contribute to the oxygen consumption. The hard Mopani woods are better than softer ones in this respect.

Don't overstock, and overfeed. If the filtration is not up to the task, it will result in nitrite, which stops fish accessing the oxygen in the water.

Look at the fish's behaviour to see if there is a problem with oxygen levels. Are they breathing effortlessly, or do they have a fast gill rate? Do they come and stick to the glass near the filter outlet after dark (a sure sign of poor oxygen)?

Some of these have been mentioned already, but it's worth repeating.

Personally I think the points Racoll mentioned are the most important

Not only because of the oxygen, but also, fish which require hig oxygen levels are, mostly, found high in the rivers. In those parts the water does not contain many bacteria, and these fishes are, therefore, rather sensitive towards such bacteria.

What do you need to do to keep these bacteria on a level as low as possible: keep the tank clean, in order to withhold them food.

Therefore a second argument for Racolls advise