Using ground probes in aquariums

Discussion in 'Reef Aquarium Discussion' started by Brew12, Oct 20, 2016.

  1. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Squad Leader Partner Member 2019 Reef Tank 365 Build Thread Contributor Article Contributor North Alabama Reef Club

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    The one you have pictured is UL listed.
     
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  2. vetteguy53081

    vetteguy53081 Well known Member R2R Supporter Partner Member 2019 R2R Secret Santa Reef Tank 365 Build Thread Contributor Article Contributor

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  3. LC8Sumi

    LC8Sumi Member

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    Great topic! What should I do if I don't have a ground in my home (apartment, 3rd floor)? I have a GFCI though, but I'm running the tank and all equipment in it from an UPS, so the GFCI doesn't help much, as the UPS will remain online if the GFCI trips. I guess I should install another GFCI downstream of the UPS. Do these in-line GFCI's need to be manually reset when power is back online?
     
  4. vetteguy53081

    vetteguy53081 Well known Member R2R Supporter Partner Member 2019 R2R Secret Santa Reef Tank 365 Build Thread Contributor Article Contributor

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    Use that. The GFCI has a ground. Simply connect to that screw.

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  5. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Squad Leader Partner Member 2019 Reef Tank 365 Build Thread Contributor Article Contributor North Alabama Reef Club

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    Thanks!

    There isn't much point in running a ground probe unless you have something close you know is grounded. I put this together which may give you an idea on how you can implement GFCI on the other side of the UPS. They will stay hot when power is restored.
    https://www.reef2reef.com/threads/diy-gfci-installation.342874/
     
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  6. LC8Sumi

    LC8Sumi Member

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    Thank you! My GFCI doesn't have a ground:) It has 4 connection: 1 for live in, 1 for neutral in, 1 for live out and 1 for neutral out.
     
  7. LC8Sumi

    LC8Sumi Member

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    Thank you Sir!
     
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  8. Gobi-Wan Kenobi

    Gobi-Wan Kenobi Member

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    Should you ground the sump also, or is it covered because the tank ground is in continuity with it via the water flow?
     
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  9. Dennis McGrath

    Dennis McGrath Well-Known Member Build Thread Contributor

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    I would put a ground probe in the sump as well, in case the flow wasn't sufficient for some reason to the sump
     
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  10. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Squad Leader Partner Member 2019 Reef Tank 365 Build Thread Contributor Article Contributor North Alabama Reef Club

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    I only ground the sump and the DT is protected by the continuity of the water.

    But Dennis is correct.
    When I turn my return pump off for maintenance, my DT isn't grounded. It is a risk I don't worry about for 2 reasons. First, my system is on multiple GFCI's which should trip and keep my safe. Second, a gyre in my DT would have to fail in that short window the return pump was off to cause a problem. I consider the odds of a failure happening at this exact time to be very low.
     
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  11. Dennis McGrath

    Dennis McGrath Well-Known Member Build Thread Contributor

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    I do it not for fear of me getting shocked, it's for the tank inhabitants.
     
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  12. Dennis McGrath

    Dennis McGrath Well-Known Member Build Thread Contributor

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    And, I forgot to mention this in an earlier post, I would like to personally thank @Brew12 for the info on this thread. Had I not read it weeks ago, I wouldn't have known to check the voltage in my tanks (one was at 47 volts at times). Now I show microvolts in my tanks. Thanks again !!!
     
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  13. JakeW

    JakeW Member

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    Thanks for posting. This is often overlooked
     
  14. jcl123

    jcl123 Active Member

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    Hello, I stumbled across this thread and actually read most of it.

    I have a titanium heater and two grounding probes, because I put one of the probes in the tank directly, and I have two sumps. If you have a chiller, that is also very likely to offer a really good ground because you have a pretty large surface area of titanium in contact with the water.

    My reasons for having them are actually:
    - Prevent inaccurate readings in pH, Salinity, and ORP probes
    - Prevent things like lateral line disease in the fish (or I imagine it could affect many types of biological processes in all kinds of nasty ways)
    - Safety is a good one, for me, there are few places to ground myself while on the aquarium, hardwood floor, few other grounded surfaces I might touch...

    Some things that made me think as I read through the thread:
    - Aquarium itself acting as a giant capacitor
    - Having metal in the tank (even titanium) making a battery.... or other galvanic activity
    - Electrons shedding off PVC, although yes I think you would need allot / longs runs to really measure this
    - If you are going to talk about the PVC doing that, then you would probably include moving water itself can generate static electricity
    - So far you have only been talking about low stray voltage, I wonder if static electricity is an issue, at much higher voltages / low current

    Some other comments:
    - Grounding useless in fresh water:
    I am afraid I am going to have to disagree with you all on this one, partially from experience. I have been shocked in fresh water many times with stray voltage coming from things like power heads (those old Hagen one's were the worst). The reason this is possible is because strictly speaking it isn't really fresh water. If you are talking about pure RODI or distilled water, then sure you may have a near perfect insulator, but nothing can live in that. But, almost all freshwater has salt and all kinds of other dissolved solids in it, and it takes relatively little added to fresh water to now make it conductive. I myself run most freshwater tanks with 1 tsp/gal added to prevent things like velvet, and because live breeders tend to do better with it. It is really just a question of degree, there is so much more dissolved in salt water that the effect is just much stronger. It can go higher even than that, you can have a super-saturated solution, especially at elevated temperature, with as much as 5x the salinity as common ocean water.

    - Quality of ground: I don't know how common this might be, and I don't know if it could affect aquariums in any way I can think of at the moment. But your house is grounded either at the water main, or a large copper spike driven into the ground. And of course, your house could be old or your electrician could make a mistake, something breaks, etc. But "electrical ground" is not as simple as having it or not, there is "how good of a ground is it?" and this can be measured, I think the term used is ground potential. You can also have differences in ground potential between different circuits in the house, yes they should all be tied together, but that is not a guarantee, and also not all devices are grounded. The reason I know this is through my home theater. My theater is on an isolation transformer and it's own ground rod (which is adjusted unit it hits the needed potential), and I have to be careful how I plug all the equipment in. The purpose is to avoid the 60Hz "hum" that you can get when you have a ground loop or similar problem, in some cases even cause picture noise. And you can also get into EMF/RMF issues. Could start to become a factor as we add more and more electronic devices to our aquariums. But, the main point I want to make here is that if you are going to go to the trouble of installing ground probes and GFCI in your tank, it is probably worth actually testing the ground you are going to use. Either do this yourself if you know how / buy a tester, or have an electrician check it for you. Aside from the safety issues that is the focus of this forum, you might want to make sure it actually can do what you want it to do with say the reasons I have listed above. I think you could also have some issues with UPS units and battery backups as have been mentioned.

    GFCI tripping: I think it might be worth looking into self-resetting GFCI on this, if that can help with shutting the whole tank down while on vacation. And running multiple separate GFCI's on say heaters is a good idea. I am also going to setup my APEX to detect regular power outages (even though my house has solar and batteries), and I plan to setup something to regularly ping the APEX unit in case it loses power or even just locks up, I can get a notification right away. So this could theoretically also detect GFCI's shutting things off. I have redundant return pumps already, although I wonder if you had a leak that could trip the GFCI, if it might trip all the GFCI's regardless vs. having just one protect all the equipment. As in having multiple may not protect you.

    -JCL
     
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  15. Jomama

    Jomama Marine fish monthly R2R Supporter

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    Many members here say " I have a titanium heater so I'm grounded." I have a titanium heater that was time to replace, so I decided to remove controller use only titanium heater as ground, I did a continuity check of wire in heater, guess what I found, NO CONTINUITY!!!!. So no grounding.

    Scary, everytime since 1983, I've had a titanium ground rod in tank.
     
  16. KrustyKrab305

    KrustyKrab305 Member

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    I recently added a grounding probe to my display tank. Should a 2nd probe be added to the sump as well?

    Thank you for the right up. I'm a long time reefer and never used a probe before eventhough I had bought one years ago and just never installed it. I guess because I just never really understood its purpose.
     
  17. CraigMixedReef

    CraigMixedReef Member

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    Thanks for the info - Recently, I had an electrician check things out, and at his recommendation, I added GFCI extension plugs (outlets are behind my 125 and electrician couldn’t swap them out) I use a grounding probe in my tank and also in my sump. I feel much less stressed about putting my hands in my tank or sump these days. What got me to call the electrician was a light zap from a cheap Chinese pump (the cord was frayed at the base). Let’s be careful out there!
     
  18. Jomama

    Jomama Marine fish monthly R2R Supporter

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    There's GFCI strip outlet, just plug into regular outlet
     
  19. CraigMixedReef

    CraigMixedReef Member

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    Like I said - at the electricians recommendation, I added GFCI extension plugs...
     
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  20. Brew12

    Brew12 Electrical Gru Staff Member Team R2R R2R Supporter R2R Excellence Award Reef Squad Leader Partner Member 2019 Reef Tank 365 Build Thread Contributor Article Contributor North Alabama Reef Club

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    Excellent comments! I do want to dig into two points you made.
    My comments on this are mostly for clarification. Grounding is important in fresh water just like in salt water. Any metal framed piece of equipment needs to be properly grounded.

    A ground probe will not be important in a true fresh water system. The conductivity limit for tap water in the US is 1.3kilo-ohms per cm. This is almost 10x more conductive than a typical US lake. A GFCI should trip at 5mA. To get 5mA in a 120V system you need a resistance of less than 24kilo-ohms. This means you can put a bare energized conductor in the tank and if the ground probe is more than 18cm (7 inches) away, the GFCI won't even trip. In typical lake water the ground probe would need to be within 1" of an energized conductor to get a GFCI to trip. You also will have minimal induced voltages due to the lower conductivity of the water. You can still be shocked if you touch a faulted component or damaged cord so GFCI use is very important imo.

    As you add salt (make the water brackish) or add fertilizers like iron you can make the water much more conductive. At some point it may make sense to run a ground probe.

    Self resetting or auto resetting GFCI's are very important to use. Almost all GFCI's available today fit this description. This term is a bit misleading. The early GFCI's would trip on a loss of power and would need to be reset manually. The self resetting GFCI's don't actually reset, they just don't trip on a loss of power. We definitely do not want to be using a GFCI on our aquariums that trips on a loss of power.

    To my knowledge there isn't a GFCI on the market that will trip on a ground fault and then reset on it's own.
     
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