Measuring strength of bleach - tool questions.

y_not

0
Jul 24, 2012
1,084
Redmond, OR
I'm about to embark on the adventure of verifying bleach strength by measuring it using Chem Geek's posted method, or Jason Lion, both have posted it.
Bleach strength testing procedure.
I know I need @ least 2 - 1ml pipettes, since the initial measure of undilute bleach will leave residue behind that'll taint the 2nd - 1ml measure in the process.

Some of these questions are going to seem, well... newbish. Seeing as I know nothing about lab equipment... please bear with me. :)

I know from wetchem's post here: graduated-cylinder-incorrect-or-am-i-doing-it-wrong-t48136.html#p392611
That I DO NOT want the "eye dropper" style pipettes. Very inaccurate!
So I have been poking around Amazon, trying to figure out what to buy. I see the ones that wetchem linked to for pretty cheap on Amazon. But they're disposable & I have read the little colored strip inside can come loose and float around in your liquid being measured.
Is this really a problem, or was it a typical "lacking internet review"?
I'd prefer a glass, non-disposable pipette, or at least a more durable non-disposable plastic type.

I'm thinking 2 of these: Mohr Glass Pipets, Class B, 1ml
Or maybe these: 25 KIMBLE 1ml x1/100 Serological Pipets Plugged Sterile Glass
Or lastly, a few of these: Pyrex Glass Pipettes, disposable ::: 1ml in 1/100ml
They're all pretty close in price, about $10-12 for 2 or more of them. Is any one better suited than the other, or would hold up better for multiple uses, or no?

How do I get the liquid to be measured into & out of it, is a syringe sufficient, or do I need a pipette pump like this? Pipette Pump 2ml
I'd like to avoid the extra bones for the pump, trying to do this on the cheap, but if it results in massive frustration otherwise, then I wouldn't be opposed to it.
If I use a pipette pump, so as not to contaminate the second sample with high concentration bleach residue, do I need 2 of them? Or does the liquid not enter into the pump?
I ask about getting it out because I don't know if surface tension is going to be a problem for releasing it. IE. Unable to easily pour it out.

Does the liquid enter the pipette only from the top and the pointed end is sealed, or is the pointed end an opening and is sort of like a one way valve due to high surface tension?
I see some of them sold as "plugged".

As for the 100ml mixing & containment, do I really need beakers, or can I get away with these that I already have? They both have mL markings and hold 100ml /w plenty of extra room. They're both Anchor Hocking & they're new. I wash them by hand so the numbers don't come off. So far, so good.
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Are they accurate enough for these purposes, or do I need more precision since working with such a high dilution ratio in such a small volume?
Would the following be a must for what I'm doing, or does it not matter since it's not high end labware, so the accuracy is... meh?
Glass Beaker Set - 3 Sizes - 50, 100 and 250ml, Karter Scientific 214T2

Thanks! :thequeen:
 

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Yeah I know, I really don't want to spend that kind of money just to make sure I'm getting what I pay for. Defeats the purpose, ya know? ;)
It's like a $70+ kit!!

If I lived in pool country, I wouldn't even really care. But things sit on the shelf here, longer than they should. Pricing is high too. So finding the best deal is hard.

Thanks though. :)
 
The Pipettes you show on amazon need a pump or bulb to draw in the liquid. Since you are out to save money, I would suggest finding a syringe. Much cheaper, much easier and way more durable than a Pipette. I can send you a few (no needles) if you want. PM Me if you can't round some up.
 
I wouldn't be opposed to buying a pipette pump, if that cheap one I linked to would work. Does it actually draw it into the pump, or no?

Would a syringe be accurate enough?
Any idea if those anchor hocking things are accurate enough?
 
If you know the volume of your pool and measure chlorine before and after adding a know amount you can figure it out without buying any extra equipment. Another plus of this method is you are working with larger volumes so small variations in measuring are insignificant.
 
y_not said:
I wouldn't be opposed to buying a pipette pump, if that cheap one I linked to would work. Does it actually draw it into the pump, or no?

Would a syringe be accurate enough?
Any idea if those anchor hocking things are accurate enough?


Yes, the pumps pull it in and hold it. You typically over draw, then purge to the amount you want. Syringes are extremely precise...think about it, they dispense medicine into a body. They have to be dead on for that. The measuring cups are fine too, especially for what we want them for. Certified lab grade accurate, no.
 
y_not said:
I wouldn't be opposed to buying a pipette pump, if that cheap one I linked to would work. Does it actually draw it into the pump, or no?
The liquid should not be drawn into the pump. The pump is attached to one end of a serological pipette to create a vacuum that draws liquid into the pipette. The "plugged" pipettes have some sort of fiber (looks like cotton) on the end near the pump to help prevent vapor from the liquid from being drawn into the pump.

As others have mentioned, syringes would be a less expensive, equally accurate solution.
 

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