Fas/dpd

[DONNIE]

I know its critical to fill test water to proper levels and try to do the drops as exact as possible etc.....but how critical is the measurement of the DPD powder? That little scoop can be interpreted many ways.

Donnie

[JohnT]

I know its critical to fill test water to proper levels and try to do the drops as exact as possible etc.....but how critical is the measurement of the DPD powder? That little scoop can be interpreted many ways.

Donnie

Doesn't appear to be at all critical.

[chem geek]

You only need to add enough scoops to produce a consistent pink color. So if for some reason you have very high chlorine levels > 25 ppm FC, then you may find that adding the powder shows a flash of pink and then either turns brown or clear. If you then add more powder, you should get the pink and can then continue the test to titrate (count drops) until the sample becomes clear.

Richard

[CarlD]

Yeah, it's not critical--if you use too much it doesn't seem to affect the ability of the titration fluid to give an accurate reading.

I've been using it for years and you only need enough to turn the water nicely pink, no more. If it's less than two scoops, fine.

However, if you have NO chlorine, it won't turn pink at all. This is a good time to double-check with a standard OTO test kit. Ben's pH test cell also has the OTO test for chorine.

[DONNIE]

Thanks. guys. I get consistant results with 2 scoops but Im always trying to fill the scoop "just right" by taping any excess out of the little depression on the scoop.

Donnie

[CarlD]

Thanks. guys. I get consistant results with 2 scoops but Im always trying to fill the scoop "just right" by taping any excess out of the little depression on the scoop.

Donnie

Don't bother! Use less if you can--the less the better, as long as it turns pink. That way you get more tests out of it.

But be really careful to keep the powder as dry as possible. NEVER put an even slightly damp scoop in it.