KHD in-line filter

[kasso187]

What are the pros and cons of not running the inline filter?

i have a feeling that some inconsistencies I am having are related to the inline filter and want to run without it for a few weeks to see if things improve.

 

[tdhnry]

Since it's there to filter the water entering the measurement cell not using it might allow debris to collect on the ph probe. And that might result in inaccurate readings.

Did you install the filter in the right direction?

 

[kasso187]

Yes it’s the right direction and the sample size was taken by emptying tube into a graduated cylinder like others have mentioned.
in addition, the ph probe and dosing heads are properly calibrated and verified.
My inconsistency is always the daytime vs night time.
daytime, my khd and hannah (verified calibration) are as much as 0.6 dkh off (khd reads lower)
At night, the two are spot on with each other.
It’s not my alkalinity dosing, because it’s set at the same interval as my testing (6 times a day) and alk is dosed 1 hour after the khd tests

 

[paul01609]

just use a set of calibrated scales for all the fluid calculations,don’t waste your time with the ghl calculator.

 

[Lasse]

which of them differ between day and night?

Sincerely Lasse

 

[AZMSGT]

Inconsistencies in readings can come from many things. In this case I’m not to certain it would be the filter unless it’s full of crud.

How old is the unit? I found it can take a couple weeks to get a new unit to stabilize.

If it’s an older unit have you calibrated the probe recently?

Check the intake line and where it’s pulling water from. You want a spot that has no airbubbles. Also try to have the intake line submerged about halfway down. This way it’s not pulling junk off the bottom or air off the top. I have my intake line secured in my sump where it doesn’t pull air or junk.

 

[kasso187]

which of them differ between day and night?

Sincerely Lasse

Daytime reading differs. Nighttime reading is the same. I trust my Hannah checker because I verified it with 2 different know calibration fluids.

 

[kasso187]

Inconsistencies in readings can come from many things. In this case I’m not to certain it would be the filter unless it’s full of crud.

How old is the unit? I found it can take a couple weeks to get a new unit to stabilize.

If it’s an older unit have you calibrated the probe recently?

Check the intake line and where it’s pulling water from. You want a spot that has no airbubbles. Also try to have the intake line submerged about halfway down. This way it’s not pulling junk off the bottom or air off the top. I have my intake line secured in my sump where it doesn’t pull air or junk.

The unit is from November 2020, but it’s only been on my tank for about 2 weeks. Also, the doser that it’s attached to has all brand new pump heads/rollers and pump head tubes all purchased from GHL.
The intake tube is held down with a weight so it is never exposed to bubbles and air.
I do notice the inline filter itself introduces bubbles

 

[Lasse]

Daytime reading differs. Nighttime reading is the same. I trust my Hannah checker because I verified it with 2 different know calibration fluids.

I was not specific enough. I meant to ask which of the methods was most stable between day and night. Does Hanna respective GHL - as an example both show 7 at night but during daytime Hanna show 6.8 and GHL show 6.2? Do you have a procenttal adjustment set for the GHL?

Sincerely Lasse

 

[kasso187]

I was not specific enough. I meant to ask which of the methods was most stable between day and night. Does Hanna respective GHL - as an example both show 7 at night but during daytime Hanna show 6.8 and GHL show 6.2? Do you have a procenttal adjustment set for the GHL?

Sincerely Lasse

The hannah remains consistant.
During my photoperiod hours, the KHD seems to read a few points lower than hanna. Then, late at night (usually between 11pm and 1:30 am) I'll spot check with my hanna, and it will be the same as the KHD.

Maybe I have to run it a few more weeks?

What is the consensus on location of the inline filter? Is it better to have it above the water line, or submerged?

 

[Ditto]

@kasso187 did you had 7ml to the calculation at the end when you calculated your sample tube volume. You should get be getting bubbles on the water inlet. I had this issue on my one tank and I had to increase the sample tube volume to get rid of the bubble. Approx 2-4ml.

The filter insures that inner workings of the unit remain clean.

I have done filter both ways. Sumerged in the sump and then 6-8 inches from the inlet of the pump. I have found 6-8 inches or not submerged that the filter last longer.

 

[kasso187]

@kasso187 did you had 7ml to the calculation at the end when you calculated your sample tube volume. You should get be getting bubbles on the water inlet. I had this issue on my one tank and I had to increase the sample tube volume to get rid of the bubble. Approx 2-4ml.

The filter insures that inner workings of the unit remain clean.

I have done filter both ways. Sumerged in the sump and then 6-8 inches from the inlet of the pump. I have found 6-8 inches or not submerged that the filter last longer.

I have to add 7 ml or 2-4ml to my actual sample tube measurement?

 

[Ditto]

If you added the filter to your supply line you need to make sure you add an additional 7ml to account for the filter. I know some users have added an additional 2-4 when they see bubbles. So instead of adding 7ml they will add 9-11ml instead.

 

[sylvius]

Correct me if wrong but if one were going to return the waste to the tank anyway, would there be any reason to not add a little volume to ensure no bubbles and no stale water?

 

[kasso187]

If you added the filter to your supply line you need to make sure you add an additional 7ml to account for the filter. I know some users have added an additional 2-4 when they see bubbles. So instead of adding 7ml they will add 9-11ml instead.

I didn’t use ghl’s calculator. I filled the sample line completely and reversed the contents into a graduated cylinder. I do notice that the sample line barely empties completely (few bubbles), so I added 2 ml to the volume last night.