KH Director - Water sample line volume

[amps]

Hey guys. I got a new KH Director and have spent the last 2 days trying to get it to work. My PH probe calibration seems on the dot and I've done my dosing pump calibration 4 times now (all within 2%). Unfortunately, it's reading my tank at 14.5dkh and the reference solution at 10.5dkh.

My question is about the water sample tube volume that needs to be entered into GHL CC. The tube from the doser to my sump is 103cm long and I'm using the included inline filter (on the end of the sample line hanging in the sump). When I enter 103cm+16cm (doser to director tube)+12cm (the value given in the manual for the peristaltic tube) into the GHL CC calculator I get a value of 16ml, 23ml total with the included filter.

For a test, I removed the sample line at the director and primed the line until there was no air bubbles and water came out of the end. Then I pulled the filter from the sump and manually ran the pump, emptying into a graduated cylinder until the line was completely empty. I did it 3 times and got 22ml total volume each time.

When I measured the volume of just the sample tube from the sump to the doser, I got a volume of 16ml. I would think that the filter plus the peristaltic line would push the total past 22ml since the filter is supposed to be 7ml by itself.

What number should I be using? Does the software make certain assumptions and I'm throwing it off by trying to calculate things manually? Is the sample volume that important that 5-10% difference would make a 40-50% difference in readings?

AHHHH! Going crazy!

 

[esther]

@Vinny@GHLUSA any thoughts? @Ditto

 

[paul01609]

Just to give you some help I have just had similar problems,my Hanna measured 8dk the khd was showing 12 wasted loads of reagent.
what I did was prime the lines then empty them one buy one in to a pot,then I used a syringe to gauge it out perfect
now it reads same as Hanna it has been a absult nightmare,
the waste line calc was a mile out Compared to using syringe

 

[amps]

Just to give you some help I have just had similar problems,my Hanna measured 8dk the khd was showing 12 wasted loads of reagent.
what I did was prime the lines then empty them one buy one in to a pot,then I used a syringe to gauge it out perfect
now it reads same as Hanna it has been a absult nightmare,
the waste line calc was a mile out Compared to using syringe

Thanks. I wound up doing something similar when I realized that the 50ml graduated cylinder I was using was wildly inaccurate below 20ml. After recalibrating with a proper cylinder, my results are much much more accurate.

 

[paul01609]

Thanks. I wound up doing something similar when I realized that the 50ml graduated cylinder I was using was wildly inaccurate below 20ml. After recalibrating with a proper cylinder, my results are much much more accurate.

My cylinder was the same 3ml out compared to using syring,would be nice if ghl would include a calibrated cylinder in with the kh director it would save a lot of hassle

 

[amps]

My cylinder was the same 3ml out compared to using syring,would be nice if ghl would include a calibrated cylinder in with the kh director it would save a lot of hassle

Gosh yes that would be nice, especially since 0.1ml on the reagent can have such a big effect. The one I originally used came with the Neptune DOS, I'm pretty surprised how bad it was considering how expensive it was. Luckily my wife bought me a bunch of overstock chemistry glassware for Christmas one year

 

[paul01609]

That’s what I was using as well lol

 

[jschultzbass]

For anyone reading this, DO NOT USE THE LENGTH CALCULATOR. HAHA. This drove me nuts and I couldn't get accurate results until I filled the tube and emptied it into a graduated cylinder...now it's right on. You can also weigh it for even better accuracy.

 

[Kyl]

Dumb question but you guys with difficulties, are you using the inline filter, and how are you mounting it?

 

[paul01609]

Yea I’m using the filter with a suction cup on side of the sump,problem is the sample calculator,
claculator claim it holds 15ml but in reality after draining it and using a syringe shows about 8ml,checked and double checked the tubing length
now it’s bang on with my hanna

 

[Kyl]

Stated volume for the filter is ~7ml to add. That sounds about right. The tubing though yeah. I don't think it holds near what the calc does.

 

[paul01609]

The sample line with filter is 7ml my sample line is 65cm inc doser pipe and from doser to kh director

 

[Kyl]

I did find on my frag KHD that has the filter mounted sort of sideways that it can cause issues. For my DT I made a bracket to hold it off the side of the sump glass vertically, I have not had a single (outside of the first "setup" test) be wonky.

 

[LOVEROCK]

For anyone reading this, DO NOT USE THE LENGTH CALCULATOR. HAHA. This drove me nuts and I couldn't get accurate results until I filled the tube and emptied it into a graduated cylinder...now it's right on. You can also weigh it for even better accuracy.

when you emptied the tube of the doser head 1 for calibration , did you remove the tubes from the machine and emptied into the graduated cylinder , or did u just tell the doser to empty everything into the graduated cylinder , haven't gotten mines yet, just trying to understand better

 

[paul01609]

I primed the lines then emptied in to a pot and then used a syringe to work out the ml,now it bang on with my Hanna befor it was about 3dkh out

 

[Trivan]

I primed the lines then emptied in to a pot and then used a syringe to work out the ml,now it bang on with my Hanna befor it was about 3dkh out

I was off on the measurements as well, till I read this. I just empty on to a scale instead of a syringe.

 

[LOVEROCK]

I primed the lines then emptied in to a pot and then used a syringe to work out the ml,now it bang on with my Hanna befor it was about 3dkh out

does it include the sample tube and the tubing into the doser head and the line (16 cm) ? or was it just the sample line

 

[Trivan]

i did the doser tubing as well.

 

[paul01609]

Prime your line fully all the tube making sure no air in the line the disconnect fline from kh director, carfuly remove tubing from the reagent so none drips back on its self (remember you need the lines full).
the just press the button until it all empties in to a tub then I used a syringe to Measure out the fluid

 

[Member No 1]

This was on Facebook this morning, thanks to Vinny

This video explains the calibration process:
https://www.youtube.com/watch?v=v9HuLpuQkJQ&t
KH Director initial setup via app: Part 2

and

This video explains the water sample tube measurement process:
*** Start at the 3 min mark ***
https://www.youtube.com/watch?v=6s2CXNqXBWw&t
KH Director initial setup via app: Part 3