KH Director

Dogtown · Jul 10, 2018

Good news! Well partially good news. Marco's steps resolved the air exchange/vent issue. The #3 tube no longer pops off. I watch the vent tube closely and can see that it draws air in and sometimes pushes air out freely. I also changed out the doser #3 tube, shortened it, and primed them all per suggestions. Thanks all!

Took two measurements since and the KHD is still erroring out with "OK Error: Titration takes too long". I'm not seeing the PH value drop much while the reagent is being added.

Dogtown · Jul 11, 2018

After taking three measurements, all three result in OK Error: Titration takes too long. This KHD unit had been running fine for several weeks before I ran out of reagent. Then I left it alone for a few weeks waiting for my reagent and then this happened. It must be something I'm doing wrong.

PH value during the water sample phase starts at 1.7 and rises to 7.2. When the reagent addition phase starts, the PH value doesn't drop as Ditto mentioned it should. After several minutes I get the error. This seems odd because the reagent is definitely being added. I can see it being drawn from the dosing container. I even allowed a small bubble of air into the line so that I could follow the bubble up the tube and into the KHD. What next?

Support@GHLUSA · Jul 11, 2018

Did the probe sit dry during the time the unit was not testing?
I would start with a probe recalibration. Maybe even pull the probe out, and let it sit in RODI water for an hour or two...

In addition, you mentioned the probe pushed out when water enters the chamber, the first item there is the vent, but also make sure you tighten the bulkhead nut, more. The probe should be snug and not move.

Also while you're testing, you can drop the sample volume down to 60mL - this will cut the test time down.

Dogtown · Jul 11, 2018

Marco@GHLUSA said:
Did the probe sit dry during the time the unit was not testing?
I would start with a probe recalibration. Maybe even pull the probe out, and let it sit in RODI water for an hour or two...

Its hard to say if the PH probe was dry or not but it seems like a real issue. I have already calibrated the probe 3 times over the last couple of days and it adjusts to approximately these numbers each time. Still, if it was dry I see where you are going.

I will do as you suggest. Pull the probe out, let it sit in rodi water for a couple of hours, calibrate again and then retest. Thanks.

Dogtown · Jul 12, 2018

I let the PH probe sit in RODI for 5 hours and then calibrated it again. No improvement unfortunately.

The PH value starts at 1.8 and increases to around 7.9 when the water sample is added. During the reagent add phase the PH value only drops to around 7.7. During the waste water removal phase, the PH value drops all the way back to around 1.8.

What is the typical PH value you all see during your reagent addition phase?

Buddah001 · Jul 13, 2018

Ditto said:
Does anyone have any idea to not have my P4’s turn yellow blinking due to the water sample and flush of the cell of the KH not being full on the doser pump?

I was wondering why it was always blinking yellow and with the software updated on both P4 I was able to figure out why.

1 and 3 are used by the KH doser, even thou alarm in them is off. Dosing 9 I was setting up for AWC.

@Ditto did you ever figure out how to disable this?

Ditto · Jul 13, 2018

@Buddah001 - Alas no I just use the GHL app and refill my container.

Mortie31 · Jul 13, 2018

During the test, when the reagent is added a small circulation pump runs, can you feel small vibrations in the tubes? You can sometimes even see them vibrate.

reefwiser · Jul 13, 2018

Mortie31 said:
During the test, when the reagent is added a small circulation pump runs, can you feel small vibrations in the tubes? You can sometimes even see them vibrate.

This happens when the pump is pushing fluid thru the lines. Are you having a problem with the pump sucking up the fluid from the container?

Mortie31 · Jul 13, 2018

reefwiser said:
This happens when the pump is pushing fluid thru the lines. Are you having a problem with the pump sucking up the fluid from the container?

No not having a problem, my circulation pump broke a few months ago. It mixes the reagent with the sample water in the internal chamber, and can be felt / heard when it’s running.

reefwiser · Jul 13, 2018

Yes,the peristaltic pumps are small rollers squeezing a piece of tubing as the motor spins around and around. This will cause the line to move as the fluid runs thru the tubing one squeeze at a time.

Mortie31 · Jul 13, 2018

reefwiser said:
Yes,the peristaltic pumps are small rollers squeezing a piece of tubing as the motor spins around and around. This will cause the line to move as the fluid runs thru the tubing one squeeze at a time.

No not the peristaltic pumps, there is a small circulatory pump inside that mixes the reagent with chamber water

Buddah001 · Jul 13, 2018

Yep my shakes to when it is testing. As if it is mining the reagent and water to measure the ph

Buddah001 · Jul 13, 2018

Ditto said:
@Buddah001 - Alas no I just use the GHL app and refill my container.

How do you stop the alarms then? I understand how to stop the blinking yellow light but these should not be an issue since they are the supply and waste water fow the KHD? They should set it up so that those 2x dedicated pumps do not trigger a warning

Mortie31 · Jul 13, 2018

Buddah001 said:
Yep my shakes to when it is testing. As if it is mining the reagent and water to measure the ph

It is, there is a tiny cylinder circulation pump that mixes the liquids.

Mortie31 · Jul 13, 2018

Buddah001 said:
How do you stop the alarms then? I understand how to stop the blinking yellow light but these should not be an issue since they are the supply and waste water fow the KHD? They should set it up so that those 2x dedicated pumps do not trigger a warning

I set the container size to 30000ml and that way they don’t alarm/warm as often

bhuyett · Jul 14, 2018

Sorry if this has been asked already. But I just received my replacement PVC tubing from GHL. Does this just replace the Reagent tube from the Doser to the bottle then?

Mortie31 · Jul 14, 2018

bhuyett said:
Sorry if this has been asked already. But I just received my replacement PVC tubing from GHL. Does this just replace the Reagent tube from the Doser to the bottle then?

Yes mate

Mortie31 · Jul 14, 2018

Mortie31 said:
Yes mate

Sorry and from the doser to the KHD

yepreef · Jul 16, 2018

Ditto said:
The pushing off the doser has happen to me, the chamber you have to empty your waste water and the overflow waste water Are the tubes above water? I had an issue where my one waste container filled for the KH and it blew the hoses off.

On one of my KH I also noticed the tubes were not snug on the connectors, others have posted this and like them I zipped tied mine.

Where did u get those ziptie? does it work well for u? mine sometimes felt off