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are oxygen test kits useful?

brhau

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10 Jul 2020
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San Francisco, CA, USA
Hi all,

I've done some searching on dissolved oxygen meters, and they look a bit expensive. I'm wondering if there is any value in home test kits sold by companies like Sera and Salifert?

Here's my use case: My largest display tank has a very large amount of botanicals, including a piece of spider wood that takes up maybe 3/4 the width of the tank. I have floating plants (which don't appreciate high water flow) and fish that also don't appreciate high flow. So I run a sponge filter at a pretty low flow rate and keep the bubbles/output contained to that corner of the tank with water sprite and a floating plant corral (airline tubing). I'd like to know if there's enough dissolved oxygen content for the fish.

Thanks,
Ben
 

jaypeecee

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Hi @brhau

I'm wondering if there is any value in home test kits sold by companies like Sera and Salifert?

In my view, the Salifert O2 Test Kit is definitely worth using. I have one of these and it is well worth the trivial price. It will let you know if O2 is optimal or perilously low. And, colour-matching against the scale provided is straightforward. As always, ensure that colours are compared in natural daylight.

I've never used any of the Sera test kits.

JPC
 

dw1305

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nr Bath
Hi all,
I've done some searching on dissolved oxygen meters, and they look a bit expensive.
It is a shame they are so expensive, they are pretty much "plug and play" once you have one.
I'd like to know if there's enough dissolved oxygen content for the fish.
Should be. Do you have a <"Czech airlifter set-up?"> I'd try it if you don't.

If you don't have a high bioload (and the <"botanicals/ wood don't contribute much BOD">) then any water turn-over should be enough. Even though your floating plants <"don't directly add much oxygen to the water"> (their stomata are on the upper leaf surface) <"they are continually removing ammonia"> (TAN) and the microbial oxidation of ammonia to nitrate is a major consumer of dissolved oxygen.
In my view, the Salifert O2 Test Kit is definitely worth using.
I'll be honest, I'm dubious. I'm going to assume it uses the <"Winkler titration method">.

I'm actually trying to buy some more DO meters at the moment for work.

cheers Darrel
 

brhau

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San Francisco, CA, USA
It is a shame they are so expensive, they are pretty much "plug and play" once you have one.
I could try to find a suitable one used, but it's still a bit of money, especially if the result is that dissolved oxygen isn't the problem.

Should be. Do you have a <"Czech airlifter set-up?"> I'd try it if you don't.
I'll be honest, I've never heard that term before. I looked it up, and it looks quite similar in principle to a sponge filter. What's the main advantage of this setup?

Cheers,
Ben
 

jaypeecee

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I'll be honest, I'm dubious. I'm going to assume it uses the <"Winkler titration method">.
Hi @dw1305

Yes, my understanding is that the Salifert kit uses the Winkler method. May I ask - why are you dubious about the Salifert O2 Test Kit? Here's an idea - why don't we do a comparison? All we need is one or two water samples on which we each measure the DO concentration. Then, we compare results. If it turns out that the Salifert O2 Test Kit gives inaccurate results (say > +/- 20% error), then some of us may consider that acceptable for the low cost. If, on the other hand, the Salifert O2 Test Kit gives seriously inaccurate results (say > +/- 50% error), then a trip to the dustbin may be in order!

It is possible to use an ORP electrode to measure DO. I might even put it to the test when I get some spare time. :rolleyes:

JPC
 

brhau

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What symptoms are they showing?
I have chili rasbora in this tank as canaries. My paros are in a different tank and doing fine. The chilis seem to be disappearing one by one. Some of them come out of hiding after a while, so I'm not 100% sure how many I have. I started with 25. There are 3 confirmed deaths. At feeding time, I typically see between 10 and 14, but that number decreases slowly over time. Today I counted 11.

Some of the fish are bright red, vigorous and happy. Some are thin and not brightly colored. I saw one this week that wasn't eating, was tilted slightly upward, and I could see rapid gill movement. So that made me wonder about dissolved oxygen.

I've seen this kind of thing (gradual thinning of the herd) twice before with rummynose tetras and pygmy cories, never with any other fish. Haven't been able to isolate the problem in these cases.
 

sparkyweasel

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30 Jun 2011
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I saw one this week that wasn't eating, was tilted slightly upward, and I could see rapid gill movement. So that made me wonder about dissolved oxygen.
If the others are breathing normally, I would suspect gill flukes (or perhaps a gill infection) making it harder for the affected fish to obtain oxygen. Low oxygen in the water is likely to affect all the fish of a species equally. I would try treating for flukes.
hth
 

fredi

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25 Feb 2013
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I have found that the larger fish (of a single species) are affected first. In my experience, these larger fish (invariably wc) become lethargic, before the smaller fish (F1’s), not sure if the origin of the fish is relevant, i suspect its due to greater oxygen demand of the larger fish
 

brhau

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If the others are breathing normally, I would suspect gill flukes (or perhaps a gill infection) making it harder for the affected fish to obtain oxygen. Low oxygen in the water is likely to affect all the fish of a species equally. I would try treating for flukes.
hth
I've treated the tank with Prazipro. Question: I use the same siphon and buckets for all of my tanks. I'm guessing there is a risk of cross-contamination? Water parameters identical in 5 of them (extreme blackwater). The 6th tank is slightly different (100 TDS). Two of the tanks have fish in them, but they're not symptomatic.

1. Should I pre-emptively treat the tanks with fish in them, or wait to see if there are symptoms?
2. What about the tanks with no fish? One of the 3 tanks with no fish was used as a quarantine for the chili rasbora. No fish in there for the last 3 weeks or so. The other 2 have never had fish, but I do ad hoc water changes with the same equipment.

Cheers,
Ben
 

sparkyweasel

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There is a risk of cross-contamination, but probably quite small.
Some people would treat pre-emptively, some (like me) prefer to wait and see, it's personal preference. If you have enough medication left, may as well use it. If you would need to buy more, might as well wait and see. :)
Most parasites can't survive long without a host, so I wouldn't worry about the unstocked tanks.
hth
 

brhau

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If the others are breathing normally, I would suspect gill flukes (or perhaps a gill infection) making it harder for the affected fish to obtain oxygen. Low oxygen in the water is likely to affect all the fish of a species equally. I would try treating for flukes.
hth
Wanted to let you know the fish are all doing very well after treating with prazi. Thanks!
 
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