pH control using Profilux 2 Plus

[B B]

Hi,*


I looked in the manual and reread the pH topic several times. Please correct me if my understanding is incorrect or if I set this up wrong. I also tried browsing through the forums and did not really find any help there.


Theoretically:*

If I want to keep my pH at 6.9 with hysterisis set at 2, that would mean that my pH Down socket should be on at a pH of 6.91 and above, and my pH Up socket should be on at a pH of 6.79 and below.


Now for my actual " functionality" test... my pH probe is reading a value of 6.5 (uncalibrated, I'm waiting for my order of calibration solutions ) so I set my nominal value at 6.5 with the minimum hysterisis which I believe is 0.12.

Considering that right now I have my CO2 running on an inverted return pump schedule (illumination 8) I created a programmable logic function and I've labeled it as programmable logic 8. Within G8 I programmed it as "input 1 = pH Down" and "input 2 = inverted illumination 8". I used the "OR" function.

When I tried to test it last night, I was playing with my nominal pH value to see if the socket would turn off when I set my pH to 6.4 and it did not turn off. Why is that? Where did I set it up wrong? I even tried doing it without the programmable logic and set my CO2 socket directly to pH Down. And to be sure, I clicked on SAVE when I was playing around with each nominal pH value.

Is it possible that the pH control NEEDS to have a socket defined as pH Up? It is the only thing that I didn't do as I am also waiting for my dosing pump to arrive on the same order as my calibration solutions.

On a side note... can someone recommend a good product to use with a dosing pump to raise the pH safely on a fresh water planted tank? My 3x dosing pump will be dosing "Mineralize" for my RO waterchange, and "Flourish Excel" as fertilizer leaving me with 1 unused dosing ch that I will use as pH Up.

Can someone please help or guide me?

Thanks

Bryan

[Matthias]

I think you better start less complicated - only use "ph downwards" for the socket in question, without a prog. logic between

if this works than you can add the light 8 thing later

to see if the socket would turn off when I set my pH to 6.4 and it did not turn off.

if you said that you had a reading of 6.5 and then you set the nominal value to 6.4 then it is no wonder that the socket doesn't switch off

set the nominal value to reading PLUS hysteresis, then it switches off