Apex salinity possibly issue

[mcdrichj]

So I have had my apex for a few weeks now. Over the past 2 days I have noticed my salinity drop pretty drastically. I didnt really notice until today when I was at work. So in the picture below you can see a chart of my salinity compared to my return pump wattage. I made a repair to my plumbing when you see the wattage drop to 0. I made 2 repairs to fix a slight leak. Finally I did a water change two days ago and not my salinity is taking a nosedive. When I first put the probe in it was reading right with my refract. With my calculations this could indicate a leak is still present but there is not much piping and I would have leaked out about 2.5 gallons which would have left a puddle somewhere and I dont see it. So I dont think this is a leak. I'm not really sure what to make of this. I would appreciate any input. I will double check the salinity with my refract when I get home.

 

[TheHarold]

The salinity probes aren't very reliable-- a tiny bubble can effect the reading. I wouldn't be too concerned, just check when you get home.

 

[mcdrichj]

Ok, thanks for the quick reply. I just calculated it out and the leak would be substantial about 68 drips per min which I would have definitely have noticed. Especially because there is only a bulkhead and about 1' of pipe that could possibly leak water out of the system.

 

[Skipbacon]

mine also experiences occasional dropouts like that. I try to rinse/clean the probe every two weeks.

 

[Twitchy]

Compare it against your temperature, the salinity probes are highly temperature dependent... you may have a temperature swing, or the heater was slow to turn on. mine had a similar drop when the last cold front came in and the heater started being used.

 

[mcdrichj]

It doesnt appear to be abnormal. My heater is in the middle chamber of my sump and the temp probe is right next to where my overflow enters the sump so I do see some temp lag but noting crazy. My tank temp depends on the ambient temp of the room.

 

[mcdrichj]

Just as a side note the apex has been running since 12/10/19 so about 20 days hopefully the probe just needs a wash.

 

[rkpetersen]

There are indeed a lot of things that can effect the salinity/conductivity probe.
If it's in a chamber subject to microbubbles, these can collect in the probe tip. However, microbubbles usually result in false elevation of salinity, not decrease.
If the probe's cable runs alongside power cables on the way to the brain, particularly heater cables, this can also cause false readings. However, this is usually cyclic, not a downward trend like you've seen.
If something crawls into or starts to grow in the probe tip, this can also cause false readings and this can be an apparent decrease in salinity. If I had to guess, I'd say this is most likely your situation.
Recalibrating the salinity probe is actually pretty easy; always a good idea to have some extra standard packets around.

 

[mcdrichj]

There are indeed a lot of things that can effect the salinity/conductivity probe.
If it's in a chamber subject to microbubbles, these can collect in the probe tip. However, microbubbles usually result in false elevation of salinity, not decrease.
If the probe's cable runs alongside power cables on the way to the brain, particularly heater cables, this can also cause false readings. However, this is usually cyclic, not a downward trend like you've seen.
If something crawls into or starts to grow in the probe tip, this can also cause false readings and this can be an apparent decrease in salinity. If I had to guess, I'd say this is most likely your situation.
Recalibrating the salinity probe is actually pretty easy; always a good idea to have some extra standard packets around.

Thanks for the detailed explanation I actually ordered a few extra probe calibration kits about 15 min ago. The rate isnt consistent so I have all but ruled out a leak (which I was most concerned about). I will give it a good cleaning when I get home and recal when the kits come in. I dont think this could be micro bubbles because my skimmer is in the next frm where my probes are and I dont get any in my tank. I will check back in when I get home and update on the status.

 

[CindyKz]

When my apex salinity probe did that exact behavior it turned out to be stray electricity. To check just scoop some of your tank water into a cup (out of the tank) and pop the probe in.

 

[mcdrichj]

Just an update I checked my salinity and it is dead on at 35 PPT. I washed the probe out in ro/di the reading dropped to 0 and went a bit higher then where it was reading but it is still low. Currently it is reading 29.3 PPT. I really wish these probes read better. It was good for the first 2-3 weeks

 

[Redfoxtang]

Crazy you bring this up as I’m having almost the same issue. My probe was just fine then I did a water change and now it’s everywhere! Tried cleaning and making sure there was no bubbles but that didn’t help.

 

[mcdrichj]

Yeah I cleaned mine and it made little difference I ordered some cal fluid. My salinity is generally very stable because my return area in the sump is small. Below is my current reading and per my refractometer my salinity is perfect @35 PPT.