And khd off againnn

[Michael Gray]

Gonna draw 3 straight tests of the 7.5kh solution. I've noticed if I pulled out the draw line where the filter is at the very end. I noticed there is still water inside the the filter. So it's not pushing it a out. Prob a couple ml..... Still in it

 

[Michael Gray]

First test with solution was 7.6dkh. 2nd test was 7.3 with solution. I've noticed after second test almost the entire filter at end is full of solution still. It's not completely emptying the sample line at the end. Not sure if that is making a difference

3rd test 7.2. Lol.

 

[LOVEROCK]

Gonna draw 3 straight tests of the 7.5kh solution. I've noticed if I pulled out the draw line where the filter is at the very end. I noticed there is still water inside the the filter. So it's not pushing it a out. Prob a couple ml..... Still in it

If it pushes it out and sits under level will water or reagent still go into it ?

 

[Michael Gray]

I blew out remaining sample water inaide filter at end and I blew out 4.7ml.

My Hanna I just tested like 3 times and consistent as heck at 8.2 every time. I recalibrated the khd sample line 2 times. Changed it to 35ml instead of 36. Also filled sample tube all the way up to kd directed. Empties in cylinder and weighed it. 36ml so my sample volume is correct even with filter. Recalibrated drain. Running more tests now

 

[Michael Gray]

Even with the new settings. I noticed on backflush it still leaves water in the filter which is at the very end. Even after recalibrating. And also measuring volume in entire sample tube run. I wonder why it doesn't backflush this and completely push out the water from the filter. Anybody else have water left in the filter at the end? Can you check?

 

[Ditto]

I have a few drops not enough to cause any issues. Did you add 7-10ml to your sample size to
Account for the filter?

 

[Michael Gray]

I have a few drops not enough to cause any issues. Did you add 7-10ml to your sample size to
Account for the filter?

Well since I redid all this I decided to run the doser pump to fill entire sample line and filter with tank water. Then I pulled it out of the tank and drained it completely and got 36ml. So that's what I put in. Which should empty my line completely with backflush but it leaves water. And I drained the filter and it left 4.7ml

Not adding up

If I measure the 8 ft add the dose tube and kh tube and add filter. The ghl app made it like 41ml. If I remember. But I never actually weighed volume to get exact till this recent round of calibrations. And it comes out as 36ml

What do you recommend. Should I add ml slowly like add 2ml. See how much it backflushes and then add 2 more. And just add slowly until it completely just empties most of it ?

Because measuring the volume it holds. Clearly doesn't work. And calibrating sample pump. Not sure if this is the reason the testing isn't accurate but I'm assuming this is something that should be backflushing completely so I wanna atleast fix this to narrow down my equipment accuracy

 

[Ditto]

I would base it on the measure of the hose plus 7-10ml. If your hose is 8ft then put in 96 inches add 4 inches for the dosing head which is 100 inches when you get that measurement at 7-10 more ml. If you try that diss it empty?

 

[Michael Gray]

I would base it on the measure of the hose plus 7-10ml. If your hose is 8ft then put in 96 inches add 4 inches for the dosing head which is 100 inches when you get that measurement at 7-10 more ml. If you try that diss it empty?

I basically did the 8ft plus 6.4 or whatever the kh was and dosing tube of like 3.2 or whatever it was. Added filter. And it came out to 41ml. So i changed my 36 measured volume number and to 41. Which when I blew the water out of the filter I got 4.7ml. I ran it and now I can watch it blow bubbles out the filter for maybe 3 seconds and stops.
I tested it twice and 8.3 and then 8.1. Hanna is 8.2. So right now I like it. Let's see it stays consistent

 

[Tristren]

Yeah, there shouldn't be any water left in the sample tube/filter after it clears it out.
I have my filter halfway up the sample line, out of the water and held vertically. I found that when I first set it up the filter was at an angle and so was trapping some air.

The system seems quite sensitive in terms the volume coming through (which I guess relates to how these titration measurements work...). With 8' of sample tube that will be magnified for you.

When I was getting weird readings early on it was because my sample tube had shifted and it was getting air trapped in sections. Having said that, since if gotten it all set up properly it has been very solid. So it is worth the time to fiddle with the physical setup and then make sure its secure.

Cheers, Tony

 

[Michael Gray]

That's good to know my filter is at the bottom it's pretty vertical but it might be a slighhhhhhht angle. Today testing twice matching Hanna. 8.1-8.2. So far so good

 

[Tristren]

That's good to know my filter is at the bottom it's pretty vertical but it might be a slighhhhhhht angle. Today testing twice matching Hanna. 8.1-8.2. So far so good

Yeah, mine isn't perfectly straight, but it was at a more than 45° angle before.
I did use the 7.5 Reference when setting it up. I don't know how accurate I was with the sample hose length when setting it up as it was off by a chunk. But the advice from GHL was to use the offset. 12% in my case which is more than I would have done myself. I would have likely tried to figure out the setup to get it closed.
Having said that, as I say, it's been solid ever since so that was the right call it seems.

Cheers, Tony

 

[KenO]

When you get a moment read what I did to shorten the sample line and remove the inline filter on the sample line. I still have a filter but just not directly on the sample line.

What I did to shorten the KHD water sample tubing to correct inconsistent dKH readings

I was finding with my GHL KHD that my dKH numbers would bounce around. It would remain steady for several readings, then I would get numbers that were sometimes 0.5 to 0.7dKh higher than the steady state numbers. I was finding that the numbers were mostly over not under the steady state...

www.reef2reef.com

 

[Michael Gray]

Tanks been good. Turned off alk dosing because.it froze at 7.7 again for last 3 days. Hanna was 7.5. Close enough. Today I tested Hanna now 7.2. Tested again 7.3. So it seems Hanna is dropping over time but kh loves to lock on 7.7. Last like 10 tests were 7.7. I flushed system and just retested. 7.7 again lol

 

[KenO]

Tanks been good. Turned off alk dosing because.it froze at 7.7 again for last 3 days. Hanna was 7.5. Close enough. Today I tested Hanna now 7.2. Tested again 7.3. So it seems Hanna is dropping over time but kh loves to lock on 7.7. Last like 10 tests were 7.7. I flushed system and just retested. 7.7 again lol

I had that happen to me, where it locked in and wouldn't change. I can't remember what the number was. Is your KHD noisy? My internal pump went bad and I had to send my unit in for service.

 

[Michael Gray]

I had that happen to me, where it locked in and wouldn't change. I can't remember what the number was. Is your KHD noisy? My internal pump went bad and I had to send my unit in for service.

It's not noisy.

 

[KenO]

It's not noisy.

I would suggest calibrating the pumps and pH probe to see if anything changes. When I calibrate the pumps I weigh the output. 1 gram = 1 ml. I will do this 3-5 times per pump and average the numbers.

 

[Michael Gray]

This go around it just went to 7.4. Maybe the Hanna checker is just quicker to the change. Lol gonna run Hanna right now to compare it to the kh

Hanna just said 7.3. See Hanna I think is just quicker to the punch lolol