GHL KH Director Test Value 0 ***HELP***

[klvnnunez]

Hi,

I currently purchased the GHL KH Director second hand to add to my profilux 4. I've been trying to get a reading when performing a manual test. So far, all of the tests I have performed with the GHL reference liquid has been 0. I have calibrated the probe multiple times with ghl pH 7 and 9 solution. I have also vented the reagent line and made sure there are no micro bubbles in the tube. The tube line going into the reference solution is between 10 and 11 inches long with no bends. The tube taking the water sample is 52 inches long for a total of 56.7 to include the 4.7 inches of the beige tube in the doser. I have also incorporated a ghl filter to the sample line to prevent contaminats from reaching the kh director.

I have also replace the ph probe (brand new) today and I'm still getting readings of 0. I have noticed the both the ADC 1 and 2 are at 1. Before replacing the probe, the value was in the like of 28000 for both. I've been going at it for a weeks without any sustantial result. I need to also mention that when I calibrated the probe, there were different readings in ADC 1 and 2, but after the test, they show a 0 value.

I would like to get this going to start monitoring alk in the hopes of getting a stable reading to add corals in the near future. Would anyone here have some insight of what's going on or if I'm doing something wrong?

Thanks in advance

 

[klvnnunez]

I have also follow the instructions on this thread and reset the PAB system and reassigned all of the devices. I recalibrated all 3 pumps again and made sure the numbers are correct. I have tried updating the firmware of the kh director but I get communication error. I'm not sure if teh kh director is not working properly as the firmware update failed. I followed the instruction by rebooting it and pressing 'ok' as soon as it did and nothing happened. I tried calibrating again after all that and noticed the actual ADC value is alternating between 0 and 1 even when the probe is in the pH 7 solution at tank temperature. See picture

I'm out of options at this point. Maybe someone here or from GHL can potentially help.

 

[ReefnFG]

Can you double check the pH probe is connected to the correct port on the back of the unit? Do the ADC 1 & 2 values change when placed in the calibration solutions?

 

[klvnnunez]

Can you double check the pH probe is connected to the correct port on the back of the unit? Do the ADC 1 & 2 values change when placed in the calibration solutions?

Yes, I have confirmed that. As for the values changing when in the pH solution, they don't change.

 

[ReefnFG]

I would submit a ticket with GHL, those values should change when placed in different solutions. This is why you get a "0" reading on KH level. The unit cant detect a pH value change during the testing.

 

[klvnnunez]

I would submit a ticket with GHL, those values should change when placed in different solutions. This is why you get a "0" reading on KH level. The unit cant detect a pH value change during the testing.

Indeed. I have opened a ticket today. Hopefully it gets resolved quickly.

 

[ReneReef]

You state you use pH 7 and 9 calibration fluids.
The KH Director requires (maybe expects) 4 and 7.

 

[klvnnunez]

You state you use pH 7 and 9 calibration fluids.
The KH Director requires (maybe expects) 4 and 7.

I don't think it should make a difference since the range I'm going for is between 7 and nine. The probe should read the ph in the solution regardless.

I have bought new solutions, ph 4 and 9 and I'm waiting for it to arrive to test again.

 

[ReneReef]

I don't think it should make a difference since the range I'm going for is between 7 and nine. The probe should read the ph in the solution regardless.

I have bought new solutions, ph 4 and 9 and I'm waiting for it to arrive to test again.

The calibration of the pH probe in a KHD has absolutely nothing to do with the pH you aim for in your tank.

A KH test is an acid titration.
It determines the KH by measuring how much acid it takes to reach a pH of 4.2.

The software in the KHD may expect a certain range of ADC value. So using 7 instead of 4 may cause trouble.

 

[klvnnunez]

The calibration of the pH probe in a KHD has absolutely nothing to do with the pH you aim for in your tank.

A KH test is an acid titration.
It determines the KH by measuring how much acid it takes to reach a pH of 4.2.

The software in the KHD may expect a certain range of ADC value. So using 7 instead of 4 may cause trouble.

So what you're saying is that the khd probe won't hit 4 or 7 ph when they are in the solution for calibration? I can you please further explain.

 

[ReneReef]

So what you're saying is that the khd probe won't hit 4 or 7 ph when they are in the solution for calibration? I can you please further explain.

No I didn’t say that.

I said it might be a software programming thing.
And again, might, so it also might not matter. It’s just a suggestion to help trouble shoot. I didn’t build the KHD so I can’t know for sure. A KHD is supplied with pH 4 and 7 solutions, so it should be easy enough to try.

You are the one deviating from the manufacturer’s instructions here.

I have never felt the need to use pH 7 and 9 to calibrate my KHD. It’s not meant to measure in that range.

Good luck. I hope you find a fix soon.

 

[klvnnunez]

No I didn’t say that.

I said it might be a software programming thing.
And again, might, so it also might not matter. It’s just a suggestion to help trouble shoot. I didn’t build the KHD so I can’t know for sure. A KHD is supplied with pH 4 and 7 solutions, so it should be easy enough to try.

You are the one deviating from the manufacturer’s instructions here.

I have never felt the need to use pH 7 and 9 to calibrate my KHD. It’s not meant to measure in that range.

Understood. I have pH solution 4 coming in tomorrow and already have the pH 7 in hand. I will re-do the test tomorrow and see what happens. According to GHL, when the probe is calibrated and placed in either of the pH solution afterwards, its supposed to give you a reading super close to the solution pH.

 

[clawhammer]

Understood. I have pH solution 4 coming in tomorrow and already have the pH 7 in hand. I will re-do the test tomorrow and see what happens. According to GHL, when the probe is calibrated and placed in either of the pH solution afterwards, its supposed to give you a reading super close to the solution pH.

I'm currently facing the same issue, Current pH-value showing zero. I've received a new probe today but with same result. I assume my KH Director is faulty and needs sending back to GHL but it would be good if you could post a conclusion to your issue please?

 

[klvnnunez]

I actually gave up with the situation. I bought a new probe and sent the KHD to GHL for repair. When it came back, I was still getting inconsistent readings. A week or two after the KHD leaked after repairing it and it fried. Mind you, this happened when I was on vacation, worst possible situation.

I ended up buying a new KHD to give GHL a second chance. Unfortunately, the new KHD has been a nightmare to get it to give consistent reading. It swings from 7.9 to 9.2 in almost a daily basis, dosing a total of 34ml of alk around the clock every two hours. Some other days the swing is only +- .6ppm. This has been very detrimental to my coral growth as well as causing huge stress to them. Im am super fed up at this point. I am saving to move to Neptune Apex and Trident. I prefer to spend the money and have something reliable than always having to calibrate and thinker with the KHD.

In my opinion, I would say to dose manually if you dont need a lot of alk and save for another solution.

Best of luck.