Neptune Probes

[Jlahr16]

I have read that some probes are susceptible to running parallel to power cables which throws off the readings. At least for the Salinity probe. Are any of the other probes known for having issues with this as well?

I ask because I have all of my power cables running into a wire duct under my Apex controller but also want to incorporate my probes wires into the same duct. I realize this will be a problem (at least for salinity probe) so I am looking for a solution to still achieve this. I have found some cable sleeves to wrap around the probe wires that help with power Interference Link Here and was wondering if anyone has tried using this with success or failure to fixing the issue?

 

[Terence]

What a gorgeous, super-clean install. I am jealous!

In general you should not run wires that are transferring analog signals directly next to wires that have high voltages. For the most part I have found that the conductivity probe is the most susceptible to this problem but there really is no hard and fast rule. I will tell you that pumps that use high-voltage DC power like the Abyzz and Royal Exclusive do cause quite a bit of noise that can interfere with the conductivity probe. Since this is usually constant (unless it is run in a pulsing closed loop), you can generally calibrate in a way that accounts for the noise (I used two fully calibrated refractometers to help me get my tank water to the "perfect" 35ppt and then I simply used my tank water as the calibration fluid. While in general I would not recommend this method, it was necessary for me to get an "accurate" reading with my probe in the tank.

 

[Jlahr16]

What a gorgeous, super-clean install. I am jealous!

In general you should not run wires that are transferring analog signals directly next to wires that have high voltages. For the most part I have found that the conductivity probe is the most susceptible to this problem but there really is no hard and fast rule. I will tell you that pumps that use high-voltage DC power like the Abyzz and Royal Exclusive do cause quite a bit of noise that can interfere with the conductivity probe. Since this is usually constant (unless it is run in a pulsing closed loop), you can generally calibrate in a way that accounts for the noise (I used two fully calibrated refractometers to help me get my tank water to the "perfect" 35ppt and then I simply used my tank water as the calibration fluid. While in general I would not recommend this method, it was necessary for me to get an "accurate" reading with my probe in the tank.

Thanks Terrence for the compliment and the information on this :), Can you let me know the steps needed to properly manually calibrate the probe to read 35ppt after adjusting the water to the correct salinity before hand? Also, after you manually calibrate, is it possible to go back to a factory calibration or will that require another manual calibration in the future if you are no longer across a high voltage power cable. I am assuming this is the difference between Automatic probe calibration and Manual Probe calibration?

 

[Terence]

Thanks Terrence for the compliment and the information on this :), Can you let me know the steps needed to properly manually calibrate the probe to read 35ppt after adjusting the water to the correct salinity before hand? Also, after you manually calibrate, is it possible to go back to a factory calibration or will that require another manual calibration in the future if you are no longer across a high voltage power cable. I am assuming this is the difference between Automatic probe calibration and Manual Probe calibration?

I am not recommending this option at all. In fact, it will not even work if you do not understand for certain the source of the interference and if it is constant or not.

To even make this work, you should use two other calibrated sources of reference/testing. Most people do not even know how to properly calibrate a refractometer - let alone understand that they should use a seawater scale version - let alone have two of them.

Once you know your tank is at 35ppt, you simply put the probe in the tank when it asks for the 53000uf solution during the calibration process.

Again, I do NOT recommend this for the average hobbyist who just thinks that his salinty probe issues are caused by interference of some sort. Almost always salinity probe issues are caused either by A.) micro bubbles in the probe or B.) improper calibration (usually with a bubble inside the probe while it is in the calibration fluid).

 

[Terence]

Oh, BTW, I will be giving a talk on all of this salinity probe stuff at Reef-a-Palooza this coming Saturday 10/7.

https://www.neptunesystems.com/rap-meetup-2017/

 

[iLLwiLL]

How far away should probe leads be from power wires? I have a lot of panduit and 3 holes going from my electronics compartment to my sump area to seperate them but at some point in the runs the probe cables will be within an inch or so of the power (500w heater, varios return, skimmer, etc.) cables.

 

[Jlahr16]

I am not recommending this option at all. In fact, it will not even work if you do not understand for certain the source of the interference and if it is constant or not.

To even make this work, you should use two other calibrated sources of reference/testing. Most people do not even know how to properly calibrate a refractometer - let alone understand that they should use a seawater scale version - let alone have two of them.

Once you know your tank is at 35ppt, you simply put the probe in the tank when it asks for the 53000uf solution during the calibration process.

Again, I do NOT recommend this for the average hobbyist who just thinks that his salinty probe issues are caused by interference of some sort. Almost always salinity probe issues are caused either by A.) micro bubbles in the probe or B.) improper calibration (usually with a bubble inside the probe while it is in the calibration fluid).

Oh, BTW, I will be giving a talk on all of this salinity probe stuff at Reef-a-Palooza this coming Saturday 10/7.

https://www.neptunesystems.com/rap-meetup-2017/

Okay, for now I don't plan on touching this, just wanted to know in case the need arises. Will have to do a lot more research on it before hand, I haven't reconnected my probes yet anyways as I figured while I was installing my new sump it was a good time to let the salinity probe dry out and re calibrate with solutions. I cant even say there is an issue yet but wanted to start grabbing some info on it.

I am planning on being at RAP next weekend so hopefully everything works out and I can be there to listen to your information and talk to you about it a bit more. Thank you so much for your responses

 

[jml1149]

I have read that some probes are susceptible to running parallel to power cables which throws off the readings. At least for the Salinity probe. Are any of the other probes known for having issues with this as well?

I ask because I have all of my power cables running into a wire duct under my Apex controller but also want to incorporate my probes wires into the same duct. I realize this will be a problem (at least for salinity probe) so I am looking for a solution to still achieve this. I have found some cable sleeves to wrap around the probe wires that help with power Interference Link Here and was wondering if anyone has tried using this with success or failure to fixing the issue?

Wow what a clean install? Holy heck, this is next level stuff.

For what it's worth, ANY probe wire will have this issue, not just Neptune probes. The probe wire carries a very small DC reference signal, whereas the power cables carry noisy, dirty, nasty AC 60Hz power, that radiates by default. It's the nature of an AC signal.

It's always best practice to separate the types of wires, be it power, signal, communication, etc. At my day job, (large defense contractor / flying machines), we go through incredible lengths just to separate the signal lines from the power lines, for the same reason mentioned here, noise and interference.

We do use something similar to that sleeve when signals are critical, it's called overbraid. But it's important you have to know how to properly ground/terminate and maintain both ends of the sleeve to an earth ground, otherwise the sleeve isn't doing much of anything.

 

[jml1149]

How far away should probe leads be from power wires? I have a lot of panduit and 3 holes going from my electronics compartment to my sump area to seperate them but at some point in the runs the probe cables will be within an inch or so of the power (500w heater, varios return, skimmer, etc.) cables.

An inch should be fine. The problem would be if they were touching, in a bundle, or zip tied together, etc. Also, the length of the run the signal wire is in close proximity to the power wire is important. If it's only a couple of inches, probably no big deal. I normally use 12" of adjacent runs before something has to be done.

 

[jordimex]

What a gorgeous, super-clean install. I am jealous!

In general you should not run wires that are transferring analog signals directly next to wires that have high voltages. For the most part I have found that the conductivity probe is the most susceptible to this problem but there really is no hard and fast rule. I will tell you that pumps that use high-voltage DC power like the Abyzz and Royal Exclusive do cause quite a bit of noise that can interfere with the conductivity probe. Since this is usually constant (unless it is run in a pulsing closed loop), you can generally calibrate in a way that accounts for the noise (I used two fully calibrated refractometers to help me get my tank water to the "perfect" 35ppt and then I simply used my tank water as the calibration fluid. While in general I would not recommend this method, it was necessary for me to get an "accurate" reading with my probe in the tank.

how do you calibrate to your tank water? i am having that same problem, thank you

 

[Terence]

how do you calibrate to your tank water? i am having that same problem, thank you

Generally most are not having this problem - or cannot adequately determine that they are. For that reason I am not really going to give, on a forum, the step by step I did as it would not be responsible.

If you have an issue with salinity and have done all the tips I have suggested (at RAP and in a soon to be released video), then I suggest you contact support.

The advice above on cable runs is excellent. That said, there is still interference that can happen in other ways - but it is rare.