Salifert magnesium test kit help please

[Scott-CapeCoral]

This is the new kit, 2ml version.

First of all, step 5 took ~81 drops, but equaled about 1.1 ml, does that sound somewhat normal?

Next, Step 6, how do you get a ppm rating?

This is what I see: "Hold the syringe with the tip facing upward and read the position of the upper end of the black part. Each division corresponds to 0.01 ml. The magnesium concentration can be obtained from the table or by use of the following equation." That would mean each line = .01 ml? So .11 is what it's telling me, but it wasn't .11, it was 1.1 ml in step 5???

"ppm mg = (1 - reading step 6) x 1500"
Does that mean (1-1.1) x 1500?
Does that mean (1-.11) x 1500?

What am I missing here?? Ahh!......

 

[bertoni]

So you used two syringes, and the total dosed was 1.11 ml? If so, the answer is 1500 + .11 x 1500, or about 1665 ppm.

 

[Scott-CapeCoral]

Thanks Jonathan. Yes, I used all of the first 1 ml, then used .1 more.

Confused on 1500 + .11 x 1500.
Where did the the 1500 + .11 come from?

 

[rayn]

I have the same kit and only use ~50 drops. How are you getting to 80, and how big are your drops? I'm usually at the 1.15 range or 1280 now that I have it adjusted.

 

[bertoni]

Sorry, I misunderstood your number. The result is 1.1 * 1500, or 1650 ppm.

 

[Scott-CapeCoral]

wow 1650 is way too high isn't it ?

Jonathan sorry I'm still confused. I used 1.1 ml of regeant 3. Now could you take it from here and tell me what you do to get the 1650

 

[neoalchemist74]

Put it this way each hundredth of a ml. or each small line is 15 ppm so if you add 1 whol ml. or one whole syringe (which is 1500 ppm) then have to add ten more graduations(or small lines) so the syringe is on .9 of the second refill the equation is 1500+(10x15)which would be 1650.

 

[neoalchemist74]

I have the same kit and only use ~50 drops. How are you getting to 80, and how big are your drops? I'm usually at the 1.15 range or 1280 now that I have it adjusted.

Ryan I think you mean .15. Remember 1 whole syringe is 1ml.

 

[Chris27]

Simply put, 1 entire syringe equates to a measurement of 1500 ppm, so 0.1 ml of an additional syringe would add another 150 ppm equating to 1650 ppm.

When you use more then 1 syringe you can't use that equation listed in the procedure the same way. It would then change to 1.1 x 1500 = 1650

 

[Shevlin77]

I have the same kit and only use ~50 drops. How are you getting to 80, and how big are your drops? I'm usually at the 1.15 range or 1280 now that I have it adjusted.

i take the plastic nozzle off the syringe and only have about 50 drops too as the drops are bigger than when using the plastic nozzle. That might be why he has 80 for the same reading?

Do you guys take the plastic nozzle off the syringe after drawing the liquid into it?

 

[Chris27]

Why measure in drops instead of a volume as indicated on the syringe?

 

[DustinB]

Why measure in drops instead of a volume as indicated on the syringe?

Good point, there should be no reason to. Volume is what you are looking for.

One thing to note, it may not be accurate without using the nozzle. The drop size is quite a bit different, not using the tip may allow you to miss the exact color change. I can't see it being off more than 15ppm or so though. Could be a problem is you are looking to average a daily usage though.

 

[noobtothereef]

the nozzle doesnt matter if its on or off, you measure in ml's anyway, if the syringe is empty and you draw till the 2ml line you have 2ml of water drawn into it..... not sure why anybody is measuring in drops. 1650 is pretty high but rest assured if you had any byropsis its gone now im sure, many people dose that high to get rid of it. I do have the old 1ml version but isnt it the same just 2ml instead of 1? I take it the 2ml version is more accurate

 

[mr.maroonsalty]

I think it would matter for accuracy's sake. I'll take the nozzle off and chack what the difference is in a bit.

 

[DustinB]

I would argue that it does matter in the case of accuracy as stated above. The drop size without the nozzle is 2-3 times larger than with the nozzle. You may go past the exact point in which the color changes resulting in a possible reading 15-30ppm over the actual value.

Agreed, actual drop count has no relevance to the reading given a proper drop size as you are looking for the volume dispensed.

 

[bertoni]

Not using the nozzle will affect the precision, but otherwise it's fine. I think the difference is going to be comparatively small for that kit. In the future, I'd use the nozzle, though.