KH Director drifting results

[miller75]

I have noticed recently that my KH Director results drift downwards over time, it usually goes down by 0.1-0.2 dky per day.

After finally having the time to have a look at it I have realised that if I flush the measurement cell the result goes back to the correct value in line with my other test kits but start drifting down again.

I am assuming this is caused by something I have set incorrectly but I can figure it out, does anyone have any ideas?

 

[Lasse]

Have you check the vent tube - if you have it connected to your waste container - it must end above the surface - the same if it end in the aquarium/sump. Otherwise - it will suck back wate water (or aquarium water). Check also calibration of sample and waste pumps in order to se if it gives more/lesser than they are calibrated for. Do you use 80 or 100 ml as sample volume?

Sincerely Lasse

 

[miller75]

Have you check the vent tube - if you have it connected to your waste container - it must end above the surface - the same if it end in the aquarium/sump. Otherwise - it will suck back wate water (or aquarium water). Check also calibration of sample and waste pumps in order to se if it gives more/lesser than they are calibrated for. Do you use 80 or 100 ml as sample volume?

Sincerely Lasse

Hi Lasse

Vent tube is above the water, I have checked the pump calibration but I will do it again to make sure. I am currently using 80ml as the water sample.

I did buy this unit used and looking at the pipes that came with it there was no filter used (they were black!), I am wondering if there could be a blockage inside somewhere

Thanks

 

[Lasse]

Change all tubes - use the harder type - not silicon. I use normally a green-tinted pvc air hose 4/6 mm if exposed to lighting or sun. Black hoses is good too. It is very important that the tubes on the suction side are on the hard side so they not implod. You need a filter - of this type

Sincerely Lasse

 

[miller75]

Change all tubes - use the harder type - not silicon. I use normally a green-tinted pvc air hose 4/6 mm if exposed to lighting or sun. Black hoses is good too. It is very important that the tubes on the suction side are on the hard side so they not implod. You need a filter - of this type

Sincerely Lasse

Thanks again Lasse, I will give it a go

 

[Lasse]

When you are up and running - test with 100 ml sample - I prefer that size - why - I do not really know but I think it works better tan with 80 ml sample

Sincerely Lasse

 

[BeanAnimal]

I have not tried the 100ml - I use 80ml and think the results are fine. I have (honestly) not calibrated or cross checked against other kits in months. Maybe one day.

 

[lpramos]

I have had this exact same issue since August. I've tried everything and still can't fix the issue. My readings jump up crazy high or crazy low, I flush, then I get a good reading, then later, another crazy reading.

I already had a ticket open to try to resolve it. Gael is being very helpful and responds quickly, but the problem persists.

I believe this past thread was the same issue: https://www.reef2reef.com/threads/kh-director-help.730150/
There are helpful ideas in that thread. I tried them all. Still, I have the problem.

 

[lpramos]

I solved my issue. My KHD pH sensor wire was too close to my Powerbar. It appears that the power cables were introducing noise into the sensor signal, causing erratic KHD results.

1. I rerouted the pH sensor wire in front of the KHD, creating distance from the power wires.

2. I sleeved the pH sensor wire in a tinned copper sleeve.

3. I added a ferrite core where the pH sensor wire connects to the KHD.

4. I clipped a ground wire to the sleeve.

I get consistent KHD readings now!

Creating separation between the pH wire and power cables probably solved the problem, but I had already ordered the sleeve, ground wire and ferrite core and had them in hand.

I hope this helps someone.