Trident help for dosing Kalk

[BroccoliFarmer]

Good morning everyone. Looking for either help on kalk dosing or re-assurance that I am doing it right. Thank you in advance.

With the following givens:

1. Using a Kamoer Peristaltic constant duty dosing pump
2. My Trident's measurement of alkalinity is approximately 0.8 lower than what I believe my true DKH to be.
3. I do a Trident test every four hours
4. Using the following Apex schedule to turn on and off my dosing pump.

Fallback OFF​

Set OFF​

If Time 12:01 to 21:59 Then ON​

If Alkx6 < 7.45 Then ON​

If pH > 8.00 Then ON​

If Alkx6 > 7.55 Then OFF​

I am getting some fluctuations from my alkalinity that tops out in the 7.8's (converted to 8.6) and bottoms out in the 7.2 (converted to 8.0).

Here are my questions:

1. Listening to people saying that they have their alk pegged...I usually take that as minor fluctuations. Is my 0.6 fluctuation within what people consider a good tolerance?
2. If the answer to my previous question is no, any thoughts on what I could do to smooth out the peaks and the valleys? I would like to avoid going hourly on my Trident as that will just burn through reagents.

Thanks

 

[MnFish1]

Hopefully I can ask a couple questions - to me - it looks like your programming is correct and your alkalinity is correct?

I don't understand the if pH >8 then on. (i.e. what is the purpose) - since the alkalinity is what you're trying to control. It would seem to me that you would want an 'if ph > xxxx then off' - in case the trident is somehow wrong.

In any case - the changes with dosing won't occur immediately - depending on the frequency of measurements with the trident - thus - the alkalinity will fall - and once its 'somewhere' below 7.45 it will turn on. Likewise - it will turn off if it measures >7.55 - but - again depending on the frequency of the measurements - it will go above 7.55 before turning off. I think this is especially true with Kalk - which can tend to raise and drop things more quickly - depending on how you're dosing it.

Also - this assumes that your KALK is completely mixed - and your doser is working correctly (as well as the trident measurements). Good luck - hope this helps

 

[BroccoliFarmer]

Hopefully I can ask a couple questions - to me - it looks like your programming is correct and your alkalinity is correct?

I don't understand the if pH >8 then on. (i.e. what is the purpose) - since the alkalinity is what you're trying to control. It would seem to me that you would want an 'if ph > xxxx then off' - in case the trident is somehow wrong.

In any case - the changes with dosing won't occur immediately - depending on the frequency of measurements with the trident - thus - the alkalinity will fall - and once its 'somewhere' below 7.45 it will turn on. Likewise - it will turn off if it measures >7.55 - but - again depending on the frequency of the measurements - it will go above 7.55 before turning off. I think this is especially true with Kalk - which can tend to raise and drop things more quickly - depending on how you're dosing it.

Also - this assumes that your KALK is completely mixed - and your doser is working correctly (as well as the trident measurements). Good luck - hope this helps

Sorry for the delayed response..just saw this. Thank you for the response

PH above 8 - I put it this was because i have heard the higher the PH, the higher the consumption. I am trying to find a way of stabilizing the consumption. I rarely hit this and it is usually right before the end of my photo cycle. As such, putting a little extra kalk in the system for the down PH cycle which is usually when i have my alk dip. I am only dosing about 1.5 ML per minute with a constant duty peristaltic pump...very low consumption and very low rate of addition. As such, at most, this is maybe 100 ml of kalk...but rarely makes a difference.

I am using a Avast Marine Kalk strirrer monitored by an apex ph probe. PH fluctuates between 12 and 12.1..so not fully saturated but generally consistent.