DISSOLVED OXYGEN TEST KITS

[FranM]

Other than a professional, expensive digital monitor, is there a reliable test kit that measures dissolved oxygen? Now I’m getting paranoid over the amount of oxygen in my tank. Thanks, Loach!!

[Basil]

Or maybe we could discuss what we should be doing to ensure our tanks are adequately oxygenated?

[FranM]

I think my tank is adequately oxygenated. My fish don’t show signs of distress and I don’t think I’m overstocked. But now I’d like to know for sure.

[NancyD]

Fran, to me "adequate oxygenation" involves a lot of surface movement. I've never tested for oxygen levels nor do I feel the need, if there is nice rippling surface water movement all the time. The problem I see with only an airstone is "wimpy" surface agitation. The bubbles don't do all that much...Power heads or HOB filters do.

[Bas Pels]

To answer your first question, a dopplet test for oxygen may be possible to make, but the result will have no meaning.

Imagine standing neat a tank, with the kit. You take some water, and add it carefully into the measuring tube to the required level.

That is, you poor water, thought to contain little oxygen, through air which is 20 % orxygen. What happens? Oxygen will dissolve into the water

If you then measure 5, you will only know the real value will not be more then 5. And most likely, without any certainty, that it is more than the last time, when the kit said 4.

[FranM]

https://youtu.be/9Jk0AmmuLSY

I’m not trying to argue or anything but are you saying, Bas, that the guy in the video is wasting his time? Or is this type of test not the same for aquarium use?

Thanks Bas and Nancy.

[Bas Pels]

Around 2 min is the moment he is filling a measuring tubve with water. shaking it to remouve a bit of escess.

Yes, he is basically wasting his time, and te reagens

[ch.koenig]

Hi
Sorry: Brian Greene is a professional. I can't see a waste of anything. The moving is in order to dissolve the chemical indikator.
Of course: electronic measering is better but expensive.
For our hobby a test kit by JBL or else will do. Recomended is the reading of the user manual. In particular the "overflowing" of the cuvette is essential. This way you won't add oxygen of the natural environment.
Only problem for all test kits: it is difficult to find the right value, the "shades" of blue are sometimes irritating.
I did a last test series about 6 years ago, just to know. Controlled by a professionel electronic measering unit. Variations were small and mostly due to the "colouring" interpretation.
I agree that there can hardly be a lack of free oxygen in a tank with the right loach set-up. Means: no overstaff, not to high temperature, not over-planted (oxygen consumption at night), not overfed (permanent oxygen consumption); with strong water movement at the surface.
Cheers Charles

[FranM]

Thanks, Charles.

So, in the states, which test kit is the best to get an idea of the dissolved oxygen in my aquarium?

Thank you.

Fran

[Bas Pels]

Whether a professional or not, what he was doing just does not make any sense from a chemical point of view. no sense at all

[ch.koenig]

No idea Fran.
In Europe it's Tetra, sera and JBL.
Red sea, Tropic Marin perhaps. I don't know if they have a seperate test out of the complete sets.
Cheers Charles