R-0870 The Dipper??

[thunderkyss]

Using the small spoon shaped end of the dipper, add one heaping dipper, or two level dippers, of R-0870 and swirl to mix. If the sample turns pink for a moment and then turns clear again, or if it turns brown, add another dipper of R-0870. If the sample remains clear the entire time, your FC level is probably zero, however it is best to verify that with an OTO chlorine test, since the FAS-DPD test is prone to the occasional false zero

The dipper isn't a very accurate measuring device. Sometimes the powder is actually a small chunk or two. Sometimes a little extra powder gets dropped into the test container. And if I use the dipper to stir the mixture, well there is always a little extra on the dipper.

Then the instructions say if the sample doesn't turn pink, add another dipper.

So, does it really matter how much R-0870 is added to the sample?

If I didn't put enough in it, will it give me a false low FC reading?

If I put too much, would it give me a false high?

 

[JasonLion]

It matters, but not very much. If you put in too little the test can read low. If you put in the right amount, or too much, or way too much then everything is fine. But if you put in way way way too much there might be some small errors, and you are wasting the powder. Generally, if you put in too little the sample will not turn pink, or it will turn pink and will then turn clear again, or will turn brown. The amount you need to use is larger when the FC level is higher.

 

[Isaac-1]

Most chemical reactions are designed around the idea of having an excess of one of the chemicals involved, from what I know of these tests, they are designed where a scoop R-0870 will be in excess for normal chlorine levels, for extremely high chlorine levels (like while shocking with high CYA levels) you might need more than 1 scoop.

So to paraphrase what Jason just said

1 scoop your ok

1 heaping scoop, your ok, and may be a good idea if you know your at shock levels

2 scoops your ok, but being wasteful

3 scoops probably ok, but your being very wasteful

the whole bottle this might have unexpected results

Ike

 

[joshs2000ss]

I just keep extra bottles of R-0870 and I dump the water into a new bottle each time, just to be sure....