KHD does NOT correct my alkalinity

[Adri-DSR]

Hi,

I have the KHD installed now for 4 days. It measure my alkalinity at 7.5. I have the nominal value set at 8.
I am using the ADD-on setting:

Volume change: 3
Limit for KH Raise: 5
Limit for KH lower: 5
Calculated adjustment: 1

Pump 4 is used to dose the KH solution 24 times a day.
My KH solution strength is 33.3 ml / 100 liter to raise 1 dKh.
Correction strength is 16.6 ml / 100 liter

My tank contains 334 liter. So to raise my Alkalinity from 7.5 to 8 the KHD needs to dose 27.82 ml extra. The calculated adjustment is 1 ml. So after 1 day my Alkalinity should be at 8.

Why is my Alkalinity still on 7.5. It already should be at 8 now after 4 days?

[arking_mark]

I think your volume change is off. For a 1 dKH deviation, you need ~100ml of your supplement. You have this set to 3ml so a .5 deviation will add 1.5ml of supplement for your next dose.

With your current setting, you will be adding roughly ~36ml for the day which is less the the nominal .5dkh you would minimally use.

[Adri-DSR]

I think your volume change is off. For a 1 dKH deviation, you need ~100ml of your supplement. You have this set to 3ml so a .5 deviation will add 1.5ml of supplement for your next dose.

With your current setting, you will be adding roughly ~36ml for the day which is less the the nominal .5dkh you would minimally use.

Mark, i dose 132 ml a day devided in 24 doses, that is 5.5 ml per dosing. That will keep my alkalinity almost at level. The KHD should take care of the rest.

To raise 1 dKH I need only 57 ml of my solution. I made a mistake with the strength.
My tank uses 2.39 dKH per day, that is where the 132 ml per day is for.

[arking_mark]

What is your 1dKH deviation setting?

[Adri-DSR]

Which setting is that?

[arking_mark]

12565

[Adri-DSR]

I don't have that setting (control) under my dosing pumps

[Adri-DSR]

12566

[arking_mark]

Looks like you may be using an older software version? Control is in the KHD settings?

[Adri-DSR]

Yes, there is but my control screen looks different. I am using the KHD Stand Alone kit. And I have downloaded the latest software.

[Adri-DSR]

It is not in the app either.

[arking_mark]

Yep. Older software version. You'll have to check documentation, but I think that "Volume Change" is for a 1dKH deviation. If so, that should be set to ~100ml for your supplement.

[Adri-DSR]

How can the app be an older version?

Same for the computer software, there is no newer version on the website of GHL.

[Adri-DSR]

Or are you using the new beta version?

[Adri-DSR]

@Vinny @Thilo

perhaps you can shine a light on this issue?

Thank you!

[arking_mark]

Could be standalone is just different from the Profilux 4 integration. Regardless, I think its the volume setting. Once corrected you should see it keep your dKH right around target.

[Adri-DSR]

The KHD shows me that it corrects the dosings with 1 ml, see screendump.

I dose 24 times a day, 24 x 1 ml extra. This is almost the complete correction to go from 7.5 to 8

Unless this 1 ml is divided by 24 dosings, then it make sense why it is still on 7.5

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[arking_mark]

Here's how I set it up and why...

1. I set doser for the nominal dose a reef tank uses per day, which is .5dKH. For my tank, I dose 6 times a day and require 24ml of supplement. So 4ml per dose. This ensures that if my tank is at target 8dKH, it still will dose this minimum amout that will be used up b4 next dose.
2. I set the 1dKH deviation volume to the actual ml needed to raise my dKH by 1. The KHD is set to measure 30 minutes b4 dosing. This ensures that after every measurement, my dKH is replenished to at least 8 plus my minimal dose.
3. I limit the max/min dose adjustment to .25dKH because I never want a larger change then that. It protects my tank from anomalous readings as well.

With these setting, I'm typically between 7.9 and 8.1 dKH. Sometimes a little higher and sometimes a little lower. The dKH consumption of my tank varries throughout the day. The more measurements / doses you do the tighter you can lock in the target dKH.

[Thilo]

@Vinny @Thilo

perhaps you can shine a light on this issue?

Thank you!

The control settings has been moved to the dosing pump settings from P4 7.24 in preparation for the IOND. For P3 and Doser 2 the firmware has not been updated yet.

[Adri-DSR]

The control settings has been moved to the dosing pump settings from P4 7.24 in preparation for the IOND. For P3 and Doser 2 the firmware has not been updated yet.

Thilo,

but why is my KHD not correcting my dosages? KHD shows that it it dosing 1 ml extra per dosage to correct my Alkalinity. But nothing is happening. The Khd measured 7.5 dKh for 4 days and last night it was even dropped back to 7.3 dKh.

If there is 1 ml extra per dosage then my dKh should already be back at 8 but this is not happening!

Can you explain why this is happening. I start to think that my KHD is faulty and does not correct the dosings

The strength of my KH solution is 16.51 ml / 100 liter to raise 1 dKh. My tank is 334 liter, so i need to dose 55.61 ml to raise 1 dKh, to raise just 0.5 dKh i have to rise 27.8 ml extra

My baseline dosage is 24 times 5.5 ml. Total dosage a day is 132 ml

The settings of my KH Director are:

Volume Change: 3 ml
Limit Raise: 5 ml
Limit Lower: 5 ml
Calculated adjustment: 1 ml.

With these settings, the KHD should dose 6.5 ml (5.5 baseline + 1ml calculated adjustment) per dosage. Then i should be back at 8 in just about 24 hours, but this is not the case.
My alkalinity is even dropping back to 7.3 now

[arking_mark]

My bet is your dKH consumption is higher than what you are dosing.

[Adri-DSR]

I think you are right. I have increased the settings and seen that the KHD also corrected the dosage. Guess I have to fine tune it now.

Thank you Mark for your advice and patience.

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[Thilo]

Perhaps the basic consumption has increased?
Try to increase the volume change slightly.

[Adri-DSR]

Perhaps the basic consumption has increased?
Try to increase the volume change slightly.I just have done that, a little too much but I see the KHD does correct the dosage now.

Thank you, Thilo

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[Thilo]

I just have done that, a little too much but I see the KHD does correct the dosage now.

Thank you, Thilo

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Yes, sorry. I've updated the page before answering but did not see that there is a new page.

[Adri-DSR]

Yes, sorry. I've updated the page before answering but did not see that there is a new page.No problem, Thilo.

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[arking_mark]

@thilo The struggle people have is what to set the 1dKH deviation volume to. There is no best practice discussed for this. My approach was to set it to actual volume needed by the supplement. In this way you are never hunting and adjusting the number. You limit the min/max to prevent quick changes. If you just use this setting with 0ml dosing, it will just bring your dKH back to target. Basically replacing consumed dKH. A simple example, if the tank is consuming 1.2dKH a day (assume constant consumption to keep it simple) and starts at 8dKH. In 4hrs it would be 7.8 and the KHD would replace the consumed amount and you'd be back to 8dKH. So you're daily variation would be 7.8 to 8.

By adding the nominal dKH dosing of .5dKH (tanks consume between .5 and 2dKH per day) you shift the dKH range to the right. For ease of math, if you set the doser to dose .6dKH a day and start with a 8dKH you will dose .1dKH and be at 8.1dKH. In 4 hours, you're dKH will drop to 7.9 from consumption and the KHD will add .1dKH on top of your .1dKH doser setting for .2dKH change or 8.1dKH. Now you're daily range is 7.9 to 8.1dKH.

[Adri-DSR]

HI Mark,

I use EZ-DSR to maintain my tank. GHL has a calculator for this method. So i used the settings that this calculator is giving me. And on the other side, the standalone version doen not have the 1 dKH deviation setting, to this makes
it al a little confusing.

But we figured it out now, only thing i have to do is to figure out the calculator now.

Thanx again for your input!

[arking_mark]

Interesting. EZ-DSR calculator does the math for you. I may dig in a little bit to see how they worked the numbers. Are you supposed to manually update the KHD periodically or is this a one time setup?

[Adri-DSR]

Interesting. EZ-DSR calculator does the math for you. I may dig in a little bit to see how they worked the numbers. Are you supposed to manually update the KHD periodically or is this a one time setup? It looks like it can be both.

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