Inconsistent alk results

[Harper]

I purchased the x10 and IV couple months ago to replace a failed alkatronic. I have been unable to get consistent results. Previously, and currently with manual hanna tests, my alk would increase after the lights go out and decrease during the day light. The hydros will show a reading that is within expectations then for 2 readings jump really high. Then return to expected. The 2 high readings seem to happen randomly sometimes there is also a single really low reading. Middle of the night, mid day, or any time. It doesn't follow any pattern, and the readings are off compared to Hanna/other testing. I turned off my calcium reactor which should have lead to a consistent down trend but instead the hydros had this random ALK.increase.

The x10 unit is hanging attached to the 8020 at the top of my stand (underside of aquarium) with the IV and reagent at the bottom of the stand. Pic attached. Also pic of hydros app readings and pic of spreadsheet with alk readings over time.

I am using the coralvue concentrated solution. I expect my preperation to be off a bit which it was with the alckatronic but the repeatability would be consistent.

I have calibrated everything several times and they maintain calibration. The IV pH tracks with the sump and salinity is spot on. I have tried my best to place the reagent tube and pH probe at the proper heights in the IV.

I'm thinking it might be some inconsistency with the dosing pumps. Since the x10 has 1 extra doser I was thinking of moving the reagent to the 4th head. Let the test run for a day or so. If the doesn't change then cycle through each head.

Any suggestions?

 

[thom_smith]

Generally an inconsistency such as this is an indication of actual alkalinity swings or air in the reagent lines. It is difficult but you really need to manually test and have THREE points of reference to confirm the results and the swings. The Hanna has a stated accuracy of +/- 0.3 dkh. And often the reagent gets stale if not used quickly which led me to storing it in the fridge. Who is to say your Hanna reference isn't incorrect without a third corresponding reference? And since alkalinity is the parameter which experiences the most frequent swings you need corresponding manual tests at the time of the X10 inconsistency to confirm the suspected inaccuracy.

The X10 IS dosing more reagent or at least THINKS it is dosing more reagent due to air. An aggressive calcium reactor may have contributed to the issue. A lower alkalinity with a simultaneous low trough in the reactor pH graph often results in an alkalinity spike several hours later. The combination of too low pH and/or too infrequent alkalinity testing could also be an issue here. Double check your calcium reactor is actually shutdown as expected? And what about kalk since they often go hand-in-hand? If those are ruled out then closely inspect reagent line for bubbles. Pay close attention to any place it meets RODI tubing, push-connect fittings or the pump heads themselves. These are often the culprits. Other factors which contribute to inaccurate results and pH calibration, pump calibration and reagent dilution. These however are more often than not consistently inaccurate results. Honestly, with limited review of your description and alkalinity graph I'm kind of thinking these are legitimate swings. Open a case with support@coralvue.com to get another set of eyes on it.

 

[Matthew Cantu]

Generally an inconsistency such as this is an indication of actual alkalinity swings or air in the reagent lines. It is difficult but you really need to manually test and have THREE points of reference to confirm the results and the swings. The Hanna has a stated accuracy of +/- 0.3 dkh. And often the reagent gets stale if not used quickly which led me to storing it in the fridge. Who is to say your Hanna reference isn't incorrect without a third corresponding reference? And since alkalinity is the parameter which experiences the most frequent swings you need corresponding manual tests at the time of the X10 inconsistency to confirm the suspected inaccuracy.

The X10 IS dosing more reagent or at least THINKS it is dosing more reagent due to air. An aggressive calcium reactor may have contributed to the issue. A lower alkalinity with a simultaneous low trough in the reactor pH graph often results in an alkalinity spike several hours later. The combination of too low pH and/or too infrequent alkalinity testing could also be an issue here. Double check your calcium reactor is actually shutdown as expected? And what about kalk since they often go hand-in-hand? If those are ruled out then closely inspect reagent line for bubbles. Pay close attention to any place it meets RODI tubing, push-connect fittings or the pump heads themselves. These are often the culprits. Other factors which contribute to inaccurate results and pH calibration, pump calibration and reagent dilution. These however are more often than not consistently inaccurate results. Honestly, with limited review of your description and alkalinity graph I'm kind of thinking these are legitimate swings. Open a case with support@coralvue.com to get another set of eyes on it.

I have had trouble with air bubbles in dosing lines. If the tubing is properly pushed all the way in the doser tube connector and tightened with the screw there shouldn't be any air leaks right? If there are leaks it would be most likely not properly set up.
But also when it comes to RODI tubing and push connect fittings. Would the problem be from the tubing not being pushed far enough in? Or just the tubing or fitting being inadequate and faulty?
I guess the frustrating part is that I always hear these things and it is just difficult to get to the true cause of the issue in regards to the air bubbles.

 

[thom_smith]

I have had trouble with air bubbles in dosing lines. If the tubing is properly pushed all the way in the doser tube connector and tightened with the screw there shouldn't be any air leaks right? If there are leaks it would be most likely not properly set up.
But also when it comes to RODI tubing and push connect fittings. Would the problem be from the tubing not being pushed far enough in? Or just the tubing or fitting being inadequate and faulty?
I guess the frustrating part is that I always hear these things and it is just difficult to get to the true cause of the issue in regards to the air bubbles.

All of the above. If calibrating immediately or even shortly after priming then the pumps may well calibrate correctly. Then sitting idle for four or six or more hours in between tests afterwards gives opportunity for air to enter the lines. And it can enter from anywhere that doesn't have a good seal. More often than not I see it at the connection to the dosing heads themselves or if trying to directly interface the silicon tubing to push-connect fittings without a stem/barb adapter. Problems such as this are not unique to the X10 but rather dosing pumps in general.

 

[Matthew Cantu]

All of the above. If calibrating immediately or even shortly after priming then the pumps may well calibrate correctly. Then sitting idle for four or six or more hours in between tests afterwards gives opportunity for air to enter the lines. And it can enter from anywhere that doesn't have a good seal. More often than not I see it at the connection to the dosing heads themselves or if trying to directly interface the silicon tubing to push-connect fittings without a stem/barb adapter. Problems such as this are not unique to the X10 but rather dosing pumps in general.

Thanks. Yeah that is what I figured was the case. I'm hoping I can figure out the issue so I can ensure that that is not skewing the results.
I have a stem/barb adapter currently. It was 1/4" so it was difficult to get the tubing on there well.
I have 3/16" stem/barb adapters I just got and tiny hose clamps. So hopefully doing that will help, and then also redoing the tubing connected to the dosing heads themselves.
Maybe the RODI cuts not being straight enough is affecting things too.
I have heard of people using RODI check valves.
I am tempted to just have RODI tubing running from the dosing container into a RODI check valve and then converting to the hose adapter to the doser head.
It might be overkill but I am willing to try that.

Also when I was setting up the X10/IV I was a bit hesitant with the dosing tubing connecting to rigid tubing. I feel air will definitely get in there.
I'm hoping there is room for a small ziptie. But I'm not sure if that will be enough.

 

[thom_smith]

Thanks. Yeah that is what I figured was the case. I'm hoping I can figure out the issue so I can ensure that that is not skewing the results.
I have a stem/barb adapter currently. It was 1/4" so it was difficult to get the tubing on there well.
I have 3/16" stem/barb adapters I just got and tiny hose clamps. So hopefully doing that will help, and then also redoing the tubing connected to the dosing heads themselves.
Maybe the RODI cuts not being straight enough is affecting things too.
I have heard of people using RODI check valves.
I am tempted to just have RODI tubing running from the dosing container into a RODI check valve and then converting to the hose adapter to the doser head.
It might be overkill but I am willing to try that.

Also when I was setting up the X10/IV I was a bit hesitant with the dosing tubing connecting to rigid tubing. I feel air will definitely get in there.
I'm hoping there is room for a small ziptie. But I'm not sure if that will be enough.

I use the 1/4 stem to 3/16 barbs. With them I don't think you'll need to goto the zip tie extremes. The Kamoer heads can be a little problematic though. I sometimes think you need the Goldilocks touch with the threaded heads. Not tight enough and you havent got a good seal. Or to tight and the threads actually slice and cut into the tubing. But just right... And I have found the best solution for the rigid tubing at the iV is just careful persistence. Push the silicon tubing such that the acrylic tubing is inserted a fair bit. Don't position the silicon tubing where there is any stress, even its own weight, pulling downward to potentially kink the tubing.

 

[Harper]

Thanks for the insight. Troubleshooting this is difficult as there are so many different possibilities. Was hoping something in my set up stuck out as an obvious issue because it's going to be difficult to do a lot of consistent troubleshooting for the next few weeks.

I switched the reagent head from 3 to 4 and see the same inconsistency. I do hear what sounds like a stuck gear from time to time during the fill/clean. Kind of like a squealing or sticking sound. At the moment I will cycle the fill head to the 4th pump. Then drain head off needed.

I will replace the junction on the reagent reservoir with just the tube into the reagent. Seems like a likely place for air.

I think that the consistent salinity and test pH matching sump pH indicates the unit is pulling well circulated sump water. As opposed to being interfered with by ato or something.


I think I can rule it actual alk swing. Previously I ran an alkatronic every 4 hours which did not reveal these types of alk swings. Its mainboard failed and I replaced it with the hydros. I also have measured via Hanna and mastertronic ( which runs once a day) at the same time as the hydros. Hydros swings the other 2 do not. But I think running all 3 at the same time for a couple weeks would be more conclusive.

 

[Danny]

I had a pinhole leak in one of the tubes up at the dosing pump on the input side of mine. It is hard to find a leak like that other than to use a syringe and fill tubing with water then add some pressure using the syringe to see if it leaks somewhere.

 

[Matthew Cantu]

I use the 1/4 stem to 3/16 barbs. With them I don't think you'll need to goto the zip tie extremes. The Kamoer heads can be a little problematic though. I sometimes think you need the Goldilocks touch with the threaded heads. Not tight enough and you havent got a good seal. Or to tight and the threads actually slice and cut into the tubing. But just right... And I have found the best solution for the rigid tubing at the iV is just careful persistence. Push the silicon tubing such that the acrylic tubing is inserted a fair bit. Don't position the silicon tubing where there is any stress, even its own weight, pulling downward to potentially kink the tubing.

Hmm ok, thanks! Yeah, the IV is actually below the X10 so the tubing definitely won't kink. But I'm not sure if gravity or the tubing being weighed down by the rigid piece slightly is causing the connection to loosen a bit, maybe I need to redo that tubing piece and make it a tad longer.
Thanks for the input, I think the issue is most likely in the dosing head connections then. But I will redo the other components just in case too.

 

[Matthew Cantu]

I had a pinhole leak in one of the tubes up at the dosing pump on the input side of mine. It is hard to find a leak like that other than to use a syringe and fill tubing with water then add some pressure using the syringe to see if it leaks somewhere.

Oh, interesting. Correct me if I'm wrong, but are you saying to prime the lines and then attach the syringe filled with water to the end of the tubing and push it to add the pressure? And then see if any water leaks out?

 

[Danny]

Oh, interesting. Correct me if I'm wrong, but are you saying to prime the lines and then attach the syringe filled with water to the end of the tubing and push it to add the pressure? And then see if any water leaks out?

I took the line completely off and replaced it and checked it with the syringe with it completely removed. I just plugged the end that the syringe was not attached but had it filled with water using the syringe before plugging it. It was not the tubing inside the dosing pump but a tube that went from the reservoir to the dosing pump.

 

[Harper]

It seems there I have some air leak but it's not so obvious where. At 4 hour testing I don't see air in the lines but at 12 hour testing I see bubbles. I replaced the reservoir input with just a single rigid tubing but still got air bubbles so I have the tubing by itself just to the bottom of the reservoir. Maybe next I need to try positive pressure test on the tubing with the current doesn't work.

 

[thom_smith]

It seems there I have some air leak but it's not so obvious where. At 4 hour testing I don't see air in the lines but at 12 hour testing I see bubbles. I replaced the reservoir input with just a single rigid tubing but still got air bubbles so I have the tubing by itself just to the bottom of the reservoir. Maybe next I need to try positive pressure test on the tubing with the current doesn't work.

Did the silicon tubing go directly to a push-connect fitting or did you have a 1/4 stem to 3/16 barb between the push-connect and silicon? Unless you use the stem/barb then high probability that was source.

 

[Harper]

The reservoir came with a stem that's screwed into something that then had a push connect at the bottom for ridgid tubing. Replaced that with a single 3/16 rigid tube. I removed the 3/16 tube and just have the silicone tube now. I'm still getting air. I think it's de-gassing in the tube. Maybe the reason the alkatronic used the ridiculously skinny feed tube. I leave the window open for gas exchange now if the year. Right now the air temp inside can range from 60s to 80s over a day. Maybe enough for the reagent fluid to degas during the day? That's just a guess. Probably need to try replacing all the tubing. Would it be worth trying a heater to maintain a constant temp in the resident reservoir? Like a heat pad?

The mastertronic only allows 1 alk test per day. Opened a new Hanna bottle on 12/14.

9 PM daily testing

date	hydros	Hanna	mastertronic
12/12/2023	8.57	8.8	8.7
12/13/2023	8.85	9	8.88
12/14/2023	9.63	8.4	9.13
12/15/2023	7.9	8.4	8.83
12/16/2023	7.22	8.5	9.08

 

[BAMatter]

@Harper any update on this? I’ve been getting some fairly erratic readings kind of like you described. 2 tests in line, 1 test high, rinse, repeat…

 

[Harper]

I made a little progress. Initially I had the X10 hanging from the top of my stand about 20in above the IV and reagent at the bottom of the stand. All the commercial Alk testers I have seen have the pump heads very close to the reaction chambers. I laid the X10 on the bottom of the stand right next to the IV and reagent. All the tubes are now really short. The feed and drain still reach up and over the sump, so maybe 20". I might build a stand to sit the X10, IV, and reagent at the top of the sump to shorten the feed and drain next.


The results below are since the change. It seems more reliable.

date	Time	hydros	mastertronic	Hanna
12/22	21:00	8.79	8.32	8.5
12/23	9:00	9.41
12/23	21:00	9.41	8.9	8.5
12/24	9:00	8.79
12/24	21:00	9.07	8.82	8.5
12/25	9:00	9.24
12/25	21:00	9.18	8.82	8.5
12/26	9:00	9.24

I do need to open a new bottle of Hanna as the current reads low and maybe only 8.5/8.6

 

[BAMatter]

I made a little progress. Initially I had the X10 hanging from the top of my stand about 20in above the IV and reagent at the bottom of the stand. All the commercial Alk testers I have seen have the pump heads very close to the reaction chambers. I laid the X10 on the bottom of the stand right next to the IV and reagent. All the tubes are now really short. The feed and drain still reach up and over the sump, so maybe 20". I might build a stand to sit the X10, IV, and reagent at the top of the sump to shorten the feed and drain next.
View attachment 3970

The results below are since the change. It seems more reliable.

date	Time	hydros	mastertronic	Hanna
12/22	21:00	8.79	8.32	8.5
12/23	9:00	9.41
12/23	21:00	9.41	8.9	8.5
12/24	9:00	8.79
12/24	21:00	9.07	8.82	8.5
12/25	9:00	9.24
12/25	21:00	9.18	8.82	8.5
12/26	9:00	9.24

I do need to open a new bottle of Hanna as the current reads low and maybe only 8.5/8.6

I gave a hard look at all my dosing lines last night with a flashlight… found some small air bubbles that were sneakily directly next to the dosing head nipples on both the in and out sides. Disconnected them, reseated them, and primed making sure were absolutely no bubbles this time. Going to check my other 3 heads tonight and reseat those as well. Thinking that was my issue.

 

[Danny]

I made a little progress. Initially I had the X10 hanging from the top of my stand about 20in above the IV and reagent at the bottom of the stand. All the commercial Alk testers I have seen have the pump heads very close to the reaction chambers. I laid the X10 on the bottom of the stand right next to the IV and reagent. All the tubes are now really short. The feed and drain still reach up and over the sump, so maybe 20". I might build a stand to sit the X10, IV, and reagent at the top of the sump to shorten the feed and drain next.
View attachment 3970

The results below are since the change. It seems more reliable.

date	Time	hydros	mastertronic	Hanna
12/22	21:00	8.79	8.32	8.5
12/23	9:00	9.41
12/23	21:00	9.41	8.9	8.5
12/24	9:00	8.79
12/24	21:00	9.07	8.82	8.5
12/25	9:00	9.24
12/25	21:00	9.18	8.82	8.5
12/26	9:00	9.24

I do need to open a new bottle of Hanna as the current reads low and maybe only 8.5/8.6

My iV sits above my X10 in height also. I have not had any issues. I do have a leak detector in the tray that has the iV and KHC in it so if there were a leak from either it would set off an alert and stop the X10/iV schedule and power down the KHC. So far that has not happened. The 10 gallon tank in the photo beside the KHC is not in use. The X10 was on the shelf underneath the iV and KHC. I now have the X10 mounted on a controller board beside the cabinet in the photo but it is still below the iV level.

 

[BAMatter]

My iV sits above my X10 in height also. I have not had any issues. I do have a leak detector in the tray that has the iV and KHC in it so if there were a leak from either it would set off an alert and stop the X10/iV schedule and power down the KHC. So far that has not happened. The 10 gallon tank in the photo beside the KHC is not in use. The X10 was on the shelf underneath the iV and KHC. I now have the X10 mounted on a controller board beside the cabinet in the photo but it is still below the iV level.

View attachment 3971
View attachment 3972

Look at you with the bling!

 

[Danny]

I did build the controller board and seen the sign and ordered one for the controller board. I also have a large controller board I built in my garage above my work bench. This is a older photo of it. The DA modules have been removed and a couple of Hydros controller added.