KH Director - Water sample line volume

amps

Active Member
View Badges
Joined
Jul 12, 2016
Messages
241
Reaction score
194
Location
Buffalo
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!
 

paul01609

Member
View Badges
Joined
May 20, 2020
Messages
41
Reaction score
120
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
 
OP
amps

amps

Active Member
View Badges
Joined
Jul 12, 2016
Messages
241
Reaction score
194
Location
Buffalo
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

Member
View Badges
Joined
May 20, 2020
Messages
41
Reaction score
120
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
 
OP
amps

amps

Active Member
View Badges
Joined
Jul 12, 2016
Messages
241
Reaction score
194
Location
Buffalo
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 :D
 

jschultzbass

Valuable Member
View Badges
Joined
Dec 29, 2011
Messages
1,363
Reaction score
922
Location
Cloquet, MN
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.
 

paul01609

Member
View Badges
Joined
May 20, 2020
Messages
41
Reaction score
120
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

Money money money money money money money
View Badges
Joined
May 11, 2016
Messages
2,269
Reaction score
2,688
Location
Vancouver, Canada
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

Member
View Badges
Joined
May 20, 2020
Messages
41
Reaction score
120
The sample line with filter is 7ml my sample line is 65cm inc doser pipe and from doser to kh director
 

Kyl

Money money money money money money money
View Badges
Joined
May 11, 2016
Messages
2,269
Reaction score
2,688
Location
Vancouver, Canada
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.
 

Are most hobbyists using enough live rock these days?

  • Yes

    Votes: 104 23.3%
  • No

    Votes: 155 34.7%
  • Not sure

    Votes: 178 39.8%
  • Other (please explain)

    Votes: 10 2.2%

Online statistics

Members online
803
Guests online
2,160
Total visitors
2,963
Top