"richard reynolds" wrote in message . ..
first off rays and sharks sense electrical differences and use that to hunt so YES he
noticed that he was on a 20kv wire even if a bird wont notice it. there are biological
receptors(?) (shark experts jump in and tell me what its called) that sences very very
low pockets(?) of electricity using that to find prey, and hide from prediators

OK - I would ask the next question - do they sense voltage difference
or maybe electric currents flowing? Assuming the very low impedance of
the salt water pointed here several times, it should be rather currents
because it will be most likely no significant voltage potentials in the seawater.
I am not a shark/ray expert myself - we should ask some marine biologist :-)

second you assume its a device, you make an assumption that honestly I do make myself, BUT
at the same time cant find your also assuming this stray voltage occurs FROM the tank and
goes into the sump where one of the probs are also something I cant prove either way, this
is a preditor tank, there are 2 NO flor lights above a glass plate and as its outside that
light fixture has been sealed its 100% submersiable and even without the lights its an
issue, thats the only AC in or around the tank, everything else is in the sump. IF it were
a failing device in the sump and IF it grounded to the probe so it would shock the water
in the sump not an issue. there are no closed loops/powerheads or anything else in the
tank all the electrical is in the sump

1. Fluorescent lights can be very big, sometimes the biggest source,
of electricity in the water. It is the biggest source in case of
my DIY fixture with no metal reflectors (I used glass mirrors).
Even if the lamp connectors are sealed the tube itself radiates
electromagnetic waves through the glas. Make a test, and touch
a glass part of tube with a burned starter - it will glow. It
glows from current flowing from the connectors, through the glass,
your hands to the ground. The same is when the water is grounded.

2. Assuming all other devices are in the sump, together with the probe
there is no risk that your probe will electrocute your fish when your
powerhead will loose the insulation and starts leaking electricity to
water. It will be shorted to the probe and GFCI will trip - no problem.
Unfortunately it will not cure the problem with fluorescent fixture or
any other elec. device submersed in the tank itself instead of the sump.

I say it cant be seperate it HAS to be kept together its always
a risk to livestock vs risk to ourselves. both need to be eliminated

I agree that sharks owners have bigger problems if their fish
are feeling stray voltages... But sharks in home aquariums are
a big mistake anyway... so there is another story right here :-))

Bottom line: GFCI - big YES, Grounding Probe - big NO!

again disagreeing here

I challenge you to prove your point of view based on the science :-)
I would be glad proven wrong - I am always happy to learn something new ;-)