Hanna check phosphate

[Tokyoyankee]

After pouring the powder in you have roughly a minute and a half to dissolve the powder. I usually shake vigorously to dissolve all the bit of powder. However I see in the instructional video that you only light swirl and shake to avoid micro bubbles. What's ur take and experience on this. Do you try to dissolve completely or is ok if the are still a couple of specks of powder leftover?

[Meshmez]

IMO the whole thing is dumb, and they should have given more time before the timeout...

anyway, from what i have gathered, its fine to have a few particles left, but make sure you are using the 3 minute timer (or maybe its 2 on the phosphate tester?) after you put the vial back in the reader. This time gives those last particles time to dissolve and time for the bubbles to rise out. In reality you could start the timer and then continue to shake the vial to dissolve, as i believe it only takes a reading at the end of the timer, the timer just gives the stuff mentioned above time to happen.

[Tokyoyankee]

Thanks. It's very strange how there's only a minute and a half before it timesout.

[bnumair]

u can shake it and let it rest for 3 minutes. then run ur test and skip the 3 min internal timer. just c1 and then c2.

[ReddyW]

u can shake it and let it rest for 3 minutes. then run ur test and skip the 3 min internal timer. just c1 and then c2.

Are you saying that we'll get good results without zeroing the unit with the tank water only sample? I'll have to test this.

That would be nice. The 'beat the clock' scenario they've created with the unnecessarily short timeout and hard to use reagent isn't worth the headache!

I've already been using the other cuvette to zero the unit so I don't waste a reagent when the clock beats me. The results on that have been very close.

[bnumair]

let me clarify. have c1 ready with tank water. get c2 ready with tank water+powder. mix the c2 by shaking and let it sit for 3 minutes.
put c1 in checker and hit the button to zero out. then put c2 and instead of holding the button for 3 min timer just hit the button, you will get the reading instantly.

[Pittsburgh]

Yep. I use both vials if I run out of time to mix the powder. Works just fine as long as I take care removing fingerprints from both vials as I should anyway. If there are any micro bubbles on the inside of the vial, I just put the cap on the vial, turn it horizontally and gently roll it for a few seconds.

[ReddyW]

let me clarify. have c1 ready with tank water. get c2 ready with tank water+powder. mix the c2 by shaking and let it sit for 3 minutes.
put c1 in checker and hit the button to zero out. then put c2 and instead of holding the button for 3 min timer just hit the button, you will get the reading instantly.

OK, that's pretty much what I've been doing when I don't beat the clock. There are differences in the cuvettes though. I've been able to get different readings by inserting the cuvette differently. Anymore I try to keep the 10ml mark to the front.