oxygen
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Manky Sanke
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Re: oxygen
Welcome Dizzy,
There are manual test kits which aren't as accurate as an oxygen meter but will give you the level of dissolved oxygen with sufficient accuracy for your purposes.
There are manual test kits which aren't as accurate as an oxygen meter but will give you the level of dissolved oxygen with sufficient accuracy for your purposes.
Re: oxygen
having now got myself a manual kit I did a test last night with it (nt labs) and I am confused nothing unusual for me 
but the test water when its supposed to go from black to clear it goes to a straw colour???it that what they mean by clear?I have 200lts of air going in to my nexus and no issues with koi gulping at the surface it was just purely for piece of mind.
but the test water when its supposed to go from black to clear it goes to a straw colour???it that what they mean by clear?I have 200lts of air going in to my nexus and no issues with koi gulping at the surface it was just purely for piece of mind.-
Manky Sanke
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Re: oxygen
I haven't used this kit but I've looked up the instructions and the method looks to be a fairly standard titration. These should be fairly accurate if you ensure that you hold the dropper bottle vertically so that each drop is consistently the correct volume.
When the colour change occurs, it should be unmistakably abrupt. There is only one condition, which is uncommon but is where the last drop is exactly on the edge of a colour change and the liquid partially changes colour but only by a small amount. EG with these reagents, it could be described as going from a dark black to a greyish colour that is almost a light black. That might sound odd and be difficult to visualise but would be obvious if you saw it. If that did happen, just add another drop and the change will be rapid and complete. The value you are looking for would be the number of drops up to the point where the change began to occur and not including the extra drop that completed the change.
You clearly have had a colour change from black to straw so, if the change was abrupt, (with or without the extra drop), then you have completed the titration correctly. All that you need to do now is divide by two the number of drops until the change started and you have your value of dissolved oxygen.
Out of curiosity, what was it?
When the colour change occurs, it should be unmistakably abrupt. There is only one condition, which is uncommon but is where the last drop is exactly on the edge of a colour change and the liquid partially changes colour but only by a small amount. EG with these reagents, it could be described as going from a dark black to a greyish colour that is almost a light black. That might sound odd and be difficult to visualise but would be obvious if you saw it. If that did happen, just add another drop and the change will be rapid and complete. The value you are looking for would be the number of drops up to the point where the change began to occur and not including the extra drop that completed the change.
You clearly have had a colour change from black to straw so, if the change was abrupt, (with or without the extra drop), then you have completed the titration correctly. All that you need to do now is divide by two the number of drops until the change started and you have your value of dissolved oxygen.
Out of curiosity, what was it?
Re: oxygen
hi Dizzy
just to interrupt here tetra do a good oxygen test kit which shows in various colours of pink and will probably be easier to follow
ill butt out now
dunc
just to interrupt here tetra do a good oxygen test kit which shows in various colours of pink and will probably be easier to follow
ill butt out now
dunc
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Manky Sanke
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Re: oxygen
Good point Duncan,
I don't recall having ever used that particular kit but there are only a few reliable methods that can be put into a kit and used to check for dissolved oxygen and the various shades of pink method is something I remember having used a few years ago. I don't think it will provide the same 0.5 mg/L accuracy of the titration method described above but it will give rapid results that should be accurate to about 1 mg/L which will be plenty accurate enough for koi pond oxygen parameters.
I use an array of electronic meters, including an oxygen meter, for water testing at koi shows because it gives exhibitors the confidence of seeing that the job is being done properly and that their koi are in safe hands. In the home pond environment the question to ask is, is there any point in knowing that your pond oxygen level is, say, 9.5 mg/L or will between 9 and 10 be accurate enough?
I don't recall having ever used that particular kit but there are only a few reliable methods that can be put into a kit and used to check for dissolved oxygen and the various shades of pink method is something I remember having used a few years ago. I don't think it will provide the same 0.5 mg/L accuracy of the titration method described above but it will give rapid results that should be accurate to about 1 mg/L which will be plenty accurate enough for koi pond oxygen parameters.
I use an array of electronic meters, including an oxygen meter, for water testing at koi shows because it gives exhibitors the confidence of seeing that the job is being done properly and that their koi are in safe hands. In the home pond environment the question to ask is, is there any point in knowing that your pond oxygen level is, say, 9.5 mg/L or will between 9 and 10 be accurate enough?
Re: oxygen
Hi Syd, BTW nice to meet you sunday
I find with O2 I only need to see a rough approximation of saturation or the trend and this kit suits me well enough for that purpose
of course if you wanted to monitor things like O2 used by a filtration system then a very accurate meter would be the order of the day\
cheers
dunc
I find with O2 I only need to see a rough approximation of saturation or the trend and this kit suits me well enough for that purpose
of course if you wanted to monitor things like O2 used by a filtration system then a very accurate meter would be the order of the day\
cheers
dunc
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Manky Sanke
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Re: oxygen
Good to meet you too Duncan, I'd have liked to have had time for a longer natter but you were very popular and everyone wanted to talk to you so I suppose we all shared that thought.
Re: oxygen
in answer to your question sid the drops were 5 to go from black to straw
Re: oxygen
Hi Dizzy Welcome to the forum
If you are the Dizzy from the crouch valley koi club I can pick up a sample from you at your next meeting and give it to Syd for you if that’s any help for you
If you are the Dizzy from the crouch valley koi club I can pick up a sample from you at your next meeting and give it to Syd for you if that’s any help for you
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Manky Sanke
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Re: oxygen
Dizzy,
If the NT Labs kit follows the instructions I looked up for similar methods to yours and each drop represents 0.5 mg/L, then five drops at 0.5 mg/L per drop, only represents a dissolved oxygen level of 2.5 mg/L. Koi would be suffocating if not already dead at that level. You say that none are gasping at the surface so, unless your instructions say differently, I think that makes it safe to assume that your kit works on the same principle as I described but that the strength of the reagents have been adjusted so that each drop represents 1 mg/L which would mean that you only have 5 mg/L dissolved oxygen in your pond.
That level is survivable without obvious distress but is far too low. Opinions vary as to the exact recommended level of oxygen but I think there is general agreement that 6 mg/L is the absolute minimum and that as near to saturation value as possible should be the ideal with 7 mg/L as the minimum. Achieving saturation value in an empty pond is easy but, with fish in it, achieving oxygen saturation becomes more difficult according to stocking level so at least 80% of the saturation value is what you should aim for.
If your instructions don't say "one drop equals 1 mg/L" or if any of the above seems confusing then a Tetra kit might be the best option.
Peter's idea to collect a sample from you at your next club meeting and bring it to me is a good idea but the time delay will mean that the dissolved oxygen level will change. With a few precautions, we can get round that to a large extent but the reading I would get would only be a good estimate and not accurate to one decimal place. I'll do that if you wish but it will be best if you can do your own tests.
If the NT Labs kit follows the instructions I looked up for similar methods to yours and each drop represents 0.5 mg/L, then five drops at 0.5 mg/L per drop, only represents a dissolved oxygen level of 2.5 mg/L. Koi would be suffocating if not already dead at that level. You say that none are gasping at the surface so, unless your instructions say differently, I think that makes it safe to assume that your kit works on the same principle as I described but that the strength of the reagents have been adjusted so that each drop represents 1 mg/L which would mean that you only have 5 mg/L dissolved oxygen in your pond.
That level is survivable without obvious distress but is far too low. Opinions vary as to the exact recommended level of oxygen but I think there is general agreement that 6 mg/L is the absolute minimum and that as near to saturation value as possible should be the ideal with 7 mg/L as the minimum. Achieving saturation value in an empty pond is easy but, with fish in it, achieving oxygen saturation becomes more difficult according to stocking level so at least 80% of the saturation value is what you should aim for.
If your instructions don't say "one drop equals 1 mg/L" or if any of the above seems confusing then a Tetra kit might be the best option.
Peter's idea to collect a sample from you at your next club meeting and bring it to me is a good idea but the time delay will mean that the dissolved oxygen level will change. With a few precautions, we can get round that to a large extent but the reading I would get would only be a good estimate and not accurate to one decimal place. I'll do that if you wish but it will be best if you can do your own tests.
Re: oxygen
sorry fisherman I am from the YKS in gods country
Re: oxygen
thanks for the offer syd but I am in leeds a bit of a way from you I am waiting for a a new o2 kit to be delivered hopefully today if not monday,this may be a stupid question but I will ask it anyway which is better 2 air drains running with a total of 140lits or 200ltrs direct into the nexus with no 02 direct into pond the reason I ask is the koi seem skitish when 02 is put thro drains,cheers Paul
Re: oxygen
My new tetra kit arrived just done a test at 13.4d the test said 8 having read the instructions that seems fine??