Phosphate Testing

[asylumdown]

Originally Posted by Reef Pilot

First, before you start, have your reagent pack cut, and opened/shaped ready to pour the powder into the vial. It is very important that you get all the powder into the vial really quick without spilling any.

Be sure the vial is always clean, inside and out.

After the C2 comes on, note the exact time in seconds and pour the reagent into the vial, and swirl for almost the full 3 min. It is very important that all the powder is dissolved and no micro bubbles. Then insert, close, and hold the button until the 3 min timer shows on the display. If you just press and release, you will get a reading but it will not be accurate. After the 3 min counts down, you will get your reading.

My Hanna checker readings are consistently accurate, and usually don't vary more than .01 when I have done more than one test.

Before when I was using the color test kits, they would read zero while the Hanna would read .6 and higher. It is very hard to distinguish white, and a slight off white, and they always read too low.

I use the Low Range Hanna Phosphate Checker, model HI 713 and reagents are HI 713-25.

waaaaait, you're supposed to hold the button down? Oh my I haven't done that once. My readings have probably been totally wrong.

I do notice how much of a difference a few micro bubbles can make, the difference between 0.05 and 0.00.

One of the things I've done to make the readings easier is to use both vials included in the kit, fill both with tank water, then only put the reagent in one. I use the straight water one as the C1 blank. I find that the powder that comes with the phosphate kit dissolves so slowly that by the time it' completely dissolved and the micro bubbles are well and truly gone that the checker has turned itself off by the time I'm ready to go with C2 half the time. Am I making it less accurate that way?

[Reef Pilot]

Originally Posted by asylumdown

waaaaait, you're supposed to hold the button down? Oh my I haven't done that once. My readings have probably been totally wrong.

I do notice how much of a difference a few micro bubbles can make, the difference between 0.05 and 0.00.

One of the things I've done to make the readings easier is to use both vials included in the kit, fill both with tank water, then only put the reagent in one. I use the straight water one as the C1 blank. I find that the powder that comes with the phosphate kit dissolves so slowly that by the time it' completely dissolved and the micro bubbles are well and truly gone that the checker has turned itself off by the time I'm ready to go with C2 half the time. Am I making it less accurate that way?

Yup, not holding down after C2 is a common mistake. I just use one vial, but I make sure I am ready with the powder, so I don't waste any time. You have 3 min to do your swirling, and that is enough for me to completely dissolve it. I've been told that using 2 vials is not as accurate, as there might be slight imperfections between the vials. Don't know if that is true, though. I slow down my swirling the last 15 seconds to be sure there are no bubbles.

[asylumdown]

huh, wow! I had no idea that thing had a timer on it.

Well, it looks like I need the low range checker. 0.00