KH Director

[powdertang05]

Accuracy is affected by how well you calibrated. If you think the KHD is off, it wouldn't hurt to re-run calibration on the dosing heads and possibly the pH probe. Also, how closely did you measure the line that pulls that sample (Pump #1). That directly affects the measurement sample.

I did recalibrate the ph probe and got the same values. As for length I did measure it twice but I guessed 4.6 inches on the dosing internal line. I thought I saw that somewhere. At most I could be off by .5 inch which I think wouldn’t affect accuracy to 1dkh.

 

[powdertang05]

I'd love to know too. This is the only missing feature that keeps me from recommending the KHD to everyone. Right now I can't recommend the KHD to anyone that doesn't have Profilux...

Where were you when I was buying two. Lol. [emoji23]

 

[c147258]

Hello

I’m wondering if the following is normal.

1. The waste water amount showing in the app is different from was expelled.

2. For every 20 to 25 very consistent and seemingly measurements, I will get a reading that is way off. After manually testing for another two times, it will usually go back to normal.

It looks like some sort of calibration error to me. If yes, what will possibly fix this?

Thank you.

 

[csb123]

I’m curious, do you have to use the GHL pH probe, or can you use other brands?

 

[Brew12]

I’m curious, do you have to use the GHL pH probe, or can you use other brands?

I'm sure there are other probes that would work, but its not a risk I would take. I would have 3 areas of concern. The easiest is making sure it is the correct diameter and length to not leak and reach far enough into the unit to read correctly.
The second concern is that it would need to calibrate into the proper range. A pH probe reads in millivolts. The number of millivolts changes based on the design of the probe sensors. So while a probe may advertise reading the same range, it may not output a signal compatible with the GHL calibration.
The final concern I would have is response time. Some probes will react to a change in pH faster than others. If your new probe doesn't react fast enough you would shoot through the test point.

 

[c147258]

didn't realize there were so many typos

Hello

It looks like I have some sort of calibration error. If yes, what will possibly fix this?

1. The waste water amount showing in the app is different from what is expelled.

2. For every 20 to 25 very consistent and seemingly accurate measurements, I will get a reading that is way off. After that it will usually go back to normal.


Thank you in advance.

 

[c147258]

bump!

didn't realize there were so many typos

Hello

It looks like I have some sort of calibration error. If yes, what will possibly fix this?

1. The waste water amount showing in the app is different from what is expelled.

2. For every 20 to 25 very consistent and seemingly accurate measurements, I will get a reading that is way off. After that it will usually go back to normal.


Thank you in advance.

 

[Brew12]

1. The waste water amount showing in the app is different from what is expelled.

I get much less waste water actually collected than it predicts. My guess is that the pump runs extra to make sure it clears out the previous sample and that the entire run time is calculated. It doesn't attempt to accurately measure actual water volume. I told my system that the waste container is larger than it actually is so my alarm reminding me to empty it is accurate now.

2. For every 20 to 25 very consistent and seemingly accurate measurements, I will get a reading that is way off. After that it will usually go back to normal.

Any chance you could be getting an air bubble in your reagent line that is working it's way up every few days?

 

[c147258]

Thank you.

I guess that's possible. I think the only way is to switch the reagent tube.

There are 2 sections.

1) doser to KH director
2) KH director to KH reagent

I guess they will both require the hard tubing?

I have air bubbles trapped at the connection points but these bubbles stay in the place and don't move. May be they are drawn into the KH director every now and then.

I get much less waste water actually collected than it predicts. My guess is that the pump runs extra to make sure it clears out the previous sample and that the entire run time is calculated. It doesn't attempt to accurately measure actual water volume. I told my system that the waste container is larger than it actually is so my alarm reminding me to empty it is accurate now.


Any chance you could be getting an air bubble in your reagent line that is working it's way up every few days?

 

[Brew12]

I guess that's possible. I think the only way is to switch the reagent tube.

There are 2 sections.

1) doser to KH director
2) KH director to KH reagent

I guess they will both require the hard tubing?

My KH Director came with specially recommended tubing for those two connections. It still took a week or two of operation to keep the air bubbles from forming, and I get a few days after changing reagent bottles but I think that is unavoidable.

 

[Mortie31]

My KHD to the rescue!! Now those who know me, know I’ve been somewhat challenging over my KHD and it took me over a year to turn control over to it, but for those in any doubt about the value of these devices, earlier today I got a reading of 7.6 a drop of 0.2 since my last reading, unusual as it was during lights off, but nothing to worry about then 6 hrs later a reading of 6.6 dkh... now I am wondering what’s up.... a quick check around, and low and behold a blocked dosing tube on my ATI pro 1.... I’m buffering back up to 7.8 now over the next few days...

 

[HigherStandards]

Got my KH Director up and running over a week ago! Thanks for this thread! I read it all from page 1 and I have to say that all the major contributors @WWIII @Ditto @Mortie31 @Brew12 @Matthias Gross have done very well in helping and explaining their issues/corrections/findings with us all. THANKS SO MUCH!

Finally turned control over to it and I can say for the last 3 days my ALK stays at 8.5 (sometimes goes up or down 0.1 day but its not a huge deal for me I verify with my Hanna Checker and Red Sea ALK titration.

It has been pretty straight forward setting it up actually, the most important thing is to make sure all the dosing tube measurements (length and Inner Diameter) along with dosing pump calibrations are near perfect.

The tubing that connects everything needs to be rigid enough so I can pull liquid but not too soft as air bubbles occur. Also the tubing needs to be pushed all the way to the end of the tubing connectors or air bubbles form from my experience.

My KH director test sample is 80ml, 6x daily.
Dosing with adaptive mode 12x daily.
0% display correction matches Hanna Check

- Pumps 1-3 are set @ 35ml flowrate (Fast speed 3)
- Pump 2 set @ 4ml (speed 0)

I have now setup my Slave 2.1 doser to be my ATO/ Salt topoff (replacing what's taken for testing) / Magnesium / Calcium / Amino acids.

I'd reccomend anyone who's looking to buy one of these to take the chance as I did. I got my units used from Ebay (Score!!!) And they've been awesome.

 

[Kyl]

I've tried searching the thread but it's kind of not worked out. If the sample tube volume is under-reported, will that result in the chamber not filling fully and offering a lower overall dKH reading? Trying to narrow down the variance points as much as possible while I dial this sucker in.

 

[HigherStandards]

If the sample tube volume is under-reported, will that result in the chamber not filling fully and offering a lower overall dKH reading?

How do you mean under-reported?

 

[Kyl]

If I put in 14 and the formula says it should be 18, etc.

 

[HigherStandards]

If I put in 14 and the formula says it should be 18, etc.

Are you using your number on the volume line or clicking on the Calculator icon and inputting the numbers?

 

[Kyl]

The calculator gives you the number, say 18. Instead you put a lower number in there for the kHD to use. Just trying to understand the relationship between the sample tube volume and it's impact on the test if incorrectly set lower. Initially this was due to me forgetting to add the 7ml from the in-line filter, then a typo on my phone that I didn't catch for a day or so after I changed things from shortening the sample line length a bit as it was put into the final draw spot in my sump.

 

[HigherStandards]

The calculator gives you the number, say 18. Instead you put a lower number in there for the kHD to use. Just trying to understand the relationship between the sample tube volume and it's impact on the test if incorrectly set lower. Initially this was due to me forgetting to add the 7ml from the in-line filter, then a typo on my phone that I didn't catch for a day or so after I changed things from shortening the sample line length a bit as it was put into the final draw spot in my sump.

The sample tube volume in my opinion is important due to the reversing feature of the sample water pump allowing a fresh test sample instead of residual water left in the line from the last test to get an actual reading instead of mixed results.

If the sample tube volume is incorrect I could see an issue with proper flush/fill of the test chamber

 

[HigherStandards]

The calculator gives you the number, say 18. Instead you put a lower number in there for the kHD to use.

Why would you change the number generated from the calculation of tube length and Inner diameter (if you actually did the measurements) to one lower?

 

[Kyl]

Why would you change the number generated from the calculation of tube length and Inner diameter (if you actually did the measurements) to one lower?

Initially this was due to me forgetting to add the 7ml from the in-line filter, then a typo on my phone that I didn't catch for a day or so after I changed things from shortening the sample line length a bit as it was put into the final draw spot in my sump.

^ That's why.