Backyard Aquaponics
A place to discuss aquaponics

I recently purchased a dissolved oxygen test kit (drops, like the Master Test Kit) to give me a rough idea of the dissolved oxygen in my system. I know a probe would probably be much more accurate, but this is just to get a basic idea if I'm oxygenating enough. ($20 vs. $220)

How do you read the damn results?

This is the kit I bought:


Once the drops are all in, the directions say:


So, does that mean:
Read it from the top, with the vial off to the side to compare the colors, like you do for the master test kit:


Or, does it mean put the vial on top of the color, look down through the liquid, and see which square disappears?



By the first method, I'm in the high range of DO.
By the second method, I'm in trouble.

My guess is the first method, compare the colors. I had a friend run the test with no input from me, and her guess was look down through the liquid and see which square disappears.

Thoughts?

I'd guess it'd be comparing the colour with the colour squares. To get the right colour.

Oxygen is added when the water is moved around. Try one straight from the system, try another that you've put in a water bottle and shaken the crap out of. The one that you've shaken should be far higher.

But for a commercial system, I think the probe would be a good investment. Not my money to spend though.

My interpritation is to match the colours. 8-10mg/L

I agree with Charlie

If it was 2mg/L most everything in your system would be dead so its a pretty good guess that its 8-12.

A confusing test is often worse than no test. If your doing this for real I say drop the cash and get a DO probe.

hi,
whats your water temperature? do saturation falls with rising temperature.
you might have reached maximum dosat. and could reduce energy consumption without dropping do.
ben

I wouldn't try going there without a do probe.

true!

The key here is to "place the test vial on a white part" so in my opinion this would mean that you not place it over the colored blocks to do your comparison. I would read that first test as somewhere around an 8. The position of the light lets you see the reflection of your colored blocks in the water and makes the solution look darker than it is (look closely and you'll see the distorted shape of the colored block reflected in the water in your first test image). It's critical that the volumes be right since you're reading the test from above.

If there is any doubt I'd give the manufacturer a call

Just ordered one of these kits to try out, along with another api master kit and another pump.................
I shouldnt visit these sites when bored at work

Instructions:

Add to the test cial 5ml of water.
Add 5 drops of O2-1 and swirl gently for 20 seconds. Do not shake since this could change the oxygen content of the water too much.
Add 6 drops of O2-2 and swirl gently for 15 seconds. Allow to stand for marine water 5 minutes and other types of water for 1 minute.
Add 6 drops of O2-3 and swirl for 20 seconds. Allow 30 seconds for color development.
Place the test vial on a white part of the color scheme and compare the colors by looking from above. An immediate color corresponds to an intermediate oxygen content. The values on the color chart are in mg/l (ppm) oxygen.

Try to maintain in fresh water (aquarium of garden pond) an oxygen content of 8mg/l or higher. In marine water an oxygen concentration of atleast 7mg/l is advisable. Some fish need higher oxygen concentrations.

Who reads the instructions?

Stuart 2 hours of frustration will always beat 10 minutes of reading the manual


Seriously those test are so hard to read, they must be viewed in the right light conditions, you can't read it in full sun or have any side light. You need too be in subdued light, any readings I take I do in my fernery under shade cloth and block out any side light.

That particular test is harder too read than an API test it's one colour only that is measured in shades, rather than the API test that will start with one colour and go through to another completely different colour.

For Oxygen you really need a higher resolution than that kit gives. You also need to be able to check different areas of your system. For me (and my trout) I need to know when the DO is below 6mg/l (should be never) but the rest of the time I'm checking differences between intlets and outlets with often less than 1mg/L difference.

Since Karen has a small commercial system this is a commercial discussion: drop the cash and get a good DO meter and probe. All jokes aside read the instructions, especially the care and maintenance instructions (some sensors need a bit more care than others). In a well designed system you should never get a low DO reading but the point of the meter is to eliminate O2 as a risk factor when trying to identify problems, reduce your stress levels and to tell you how much to panic when the power goes off and stays off or your come into the GH and find the FT half full.

For BYAP peoples its different because not many can justify the $600-1000 dollars for a good DO meter.