A question regarding red sea test kit pro...

[Tonyscoots84]

hey guys i figured i would bring this up and see if anyone else noticed what i have been experiencing with the syringes.

When i suck up the alk test (red liquid) or any of the other ones i get different ml once done sucking up in the syringe. For example i can get

1st time - .95ml
2nd time - .92ml
3rd time - where it should be at around .90

example





i use the same slow steady draw when I'm extracting liquid from the vial. What gives :arg: :smoker:

I just want to be as precise as possible.. If you suck up more or less then what it should be you will get a different test value which is not ok with me....

 

[kres1024]

I get the same thing with Red Sea and also with salifert
Also would like to know .

 

[Tonyscoots84]

at least I'm not the only one...

 

[edd]

your supposed to draw to the 1m line. pic shows to the top of syringe.
but i know what your saying.

 

[Tonyscoots84]

edd it said from what i remember to pull all the way up then push down so the bottom of the plunger is at the 1 ml mark....

I just can't understand why it would fluctuate so much doing the same thing over and over...

 

[Tonyscoots84]

here is the video from red sea... he also drew really fast....

http://youtu.be/bb4NnYOFneA

 

[lnevo]

Push down to the 1ml mark as stated and then measure how much liquid. "Top of the syringe" is not a good measure. But this is also why these tests have a standard error +/-

 

[Tonyscoots84]

i get that inevo what i don't understand is why does the liquid fluctuate in the syringe after you draw the liquid. As i said sometimes i get .95 to the top and can fluctuate anywhere in between...

 

[lnevo]

Yeah what i meant was draw to the top then plunge down to 1ml then measure how different each time.

Then also look at what difference .1 ml makes to your measurement. I think its like .15dkh. Whats the +/- accuracy state in the book?

These aren't the most supremely accurate syringes and i think the amt of air tgat can get in via the top/union between tip may vary...

 

[edd]

i just read the instructions, it says,
raise the plunger of the syringe until the bottom ring of the plunger is at the 1.0ml mark. the surface of the liquid will be approximately 0.1-0.15ml below the plunger.
do not try to remove the air trapped between the liquid and the plunger. this small volume of air corresponds to the liquid inside the plastic tip.

 

[Tonyscoots84]

if that is done ddd then you are not really starting with 1ml of liquid

 

[edd]

the syringe is made to hold 1.0ml not including the tip. the tip is holding what the air corresponds to.

 

[Tonyscoots84]

you have a point there edd. I'm thinking here. So the guy on the video is wrong then :iamwithst

 

[lfsmarineguy]

Are you taking the syringe apart and making sure it's clear each time or just depressing and refilling? If you don't clear it there could be leftover reagent.

Also, as stated, the air space at the top is compensation for the space in the tip. It's calibrated by design.

 

[Tonyscoots84]

lfs thats what i thought. i noticed after i cleaned out the tip it would come out perfect or very close...

 

[vio]

lfs thats what i thought. i noticed after i cleaned out the tip it would come out perfect or very close...

+1.Push down to the 1ml mark, ignore the extra air will stay on tip.

 

[BKLYNREEF123]

+1 on this Tony I feel the kit is not accurate. Some improvement should be made so the user has a definitive visual of the reagent + - to compensate for air leaves the user to feel unsure of the results. Also I noticed the color change can be hard to interpret. I was convinced this was an accurate kit when I place the order but I am less than satisfied.

 

[edd]

+1 on this Tony I feel the kit is not accurate. Some improvement should be made so the user has a definitive visual of the reagent + - to compensate for air leaves the user to feel unsure of the results. Also I noticed the color change can be hard to interpret. I was convinced this was an accurate kit when I place the order but I am less than satisfied.

+1 for color hard to interpret even with salifert, but a lot of members state
consistant parameters are more important than accuracy.

 

[BKLYNREEF123]

I hear you Edd, but how consistent can we stay without accurate results? I thought Hanna Checkers may be the solution but I have seen mixed reviews on these as well. Maybe I am asking for too much... but I feel improvement is needed. We are all willing to spend the time and money to maintain our systems, purchase products, spend time testing logging ect... I think the manufacturers need to step up to the plate and produce a better test kit. I have seen how much improvement has been made in recent years and am looking forward to whats to come.

 

[Yani1133]

The air you getting is the air your sucking up from the plastic tip attachment. If you take the plastic removable tip off you can get up to exactly 1 ml but your drops are bigger. Best thing you can do is it is what you are titrating with, subtract the air bubble space off your final volume from the calculations. And as for the different volumes everytime its why these are cheap disposable pippettes that would never be used in a lab.