KHD Add-On Mode

[chikanot]

Hello

My KHD has been up and running for more than 2 months now only for monitoring. Alkalinity control was done manually. No issues on the alkalinity accuracy, repeat-ability and it constantly match to Salifert test kit within 0.3 dKH.

3-4 days ago I am letting the KHD to control my alkalinity via Add-On mode. My preferred alk is set at 8 dKH but since letting KHD to take over the alkalinity has swing between 6.3-10.8 dKH.

Some details:
Add-On mode with Nominal dKH value is at 8dKH
It will takes 88ml-ish Fauna Marin alkalinity solutions to raise 1dKH
"Limit for raise KH" is set at 88ml
"Limit for lower KH" is set to 88ml
KHD measurement at 7am and 7pm daily
Doser 2.1 pump 2 in used for alkalinity solutions at 16 times a day.

Questions:
If I understands the manual correctly, setting such value for "limit for raise KH" and "Limit for lower KH", I am letting KHD 7-9 dKH for alkalinity bias for it to control. Am I correct on that assumptions?
Is there anyway can I retrieve Doser 2.1 pump 2 historical dosing amount?
Says at 7am KHD measures 7dKH, theoretically KHD will instruct Doser 2.1 pump 2 for 88ml additional alkalinity solution. Does this extra 88ml addition fluids is spread out evenly till the next KHD measurement at 7pm or it will dump it in one go during the next scheduled dose?

Thanks

Wazir

[mshur]

can you post screen shots of DKH , i think your settings is wrong...I will post mine later when i get home

[chikanot]

I am letting my alk to drop on its own at the moment. In the mean time I am recalibrating and opening the KHD for servicing. Then, I will re-try

[dclifford]

Says at 7am KHD measures 7dKH, theoretically KHD will instruct Doser 2.1 pump 2 for 88ml additional alkalinity solution. Does this extra 88ml addition fluids is spread out evenly till the next KHD measurement at 7pm or it will dump it in one go during the next scheduled dose?


*This is my opinion and I am open to correction. I would wait for further clarification before making a change.*
In your sample case it would add 88 to every scheduled dose up to the next measurement time. If you have 16 doses per day you are going to have 7 or 8 doses with 88 added.
Change your limits to lower numbers and this will give it smaller adjustments.
probably best to get back near 8 and then let it control from there with smaller adjustments until you find the sweet spot.

[chikanot]

Now for some reason the KHD is only measuring around 8.2-8.5 dKH even though I am not dosing any alkalinity solution. 2 brand test kit does not agrees to KHD value at all anymore.
Mattias instruct me to re-calibrate doser pump and KHD pH probe plus try to clean internal KHD mini pump. It just, no documentation/instruction give for me to follow in order to clean the mini pump.
Since it is situated right on top of the PCB, I am reluctant to proceed blind without any instructions from GHL.

11102

[MatthiasF]

Hello,

we will take care of you in our Support-system, where we have a ticket open and managing your issue there.