Starting a new topic for this, so I won’t be hijacking someone else’s thread… Not sure if people have discussed this much here…
Water is a poor conductor.
@subnoize , Rust inhibitor is used liberally in the water tank here, so the “water” is highly conductive. 
The plasma cutter is in use almost every weekend and often a night during the work-week as well, so the water table doesn’t get drained here. The rust inhibitor keeps the slats from rusting up, as well as all the tiny tiny dross in-between major cleanings. It is also nice to pull a piece of clean mild steel of the table and know it isn’t going to flash rust over-night. Here in the PNW those days are few and far inbetween, but in years past I’ve had those problems near the end of summer and the rust inhibitor has cut that right out. 
I can’t remember if there has been a discussion of rust inhibitors for water tables here…? I use food grade sodium nitrite. Super cheap for a 5lb bucket.
Are others out there using something else?
Sodium Nitrite only works when you don’t have an aluminum tank. The one I was shipped is aluminum.
For those of us with aluminum tanks, do not use sodium Nitrate as it will seriously pit and degrade the aluminum. The weld will also embrittle and may crack over time.
https://www.publish.csiro.au/ch/pdf/ch9800169
In coolant systems where Sodium Nitrite is used will commonly interface with alumium components and we discovered the alumium will pit, embrittle and eventually fail.
It’s not “right away” but drain your tank, don’t let it sit. Rinse the tanks after use. The electrical fields developed in the tanks for Plasma machines enhance the effect so be adivised.
@subnoize ,Thanks for the tip. Some further research tells me I’m in for a catastrophic failure on the water table soon. (or two years ago and I still haven’t noticed) 
I’ve been using much higher concentrations (and repeatedly refreshing it) for the past several years (higher than those mentioned in Google & Wikipedia. I almost wonder if the deposition layer of steel / dross that has been deposited
and then passivated on top of the aluminum is protecting it below the water line.
Three summers ago and again last summer I had pulled the water table off the machine and had it out on the the back lawn to do a heavy manual scrubbing with a steel wire bristle brush. There is some sort of dark purple/brown/black amalgamated “alloy” for lack of a better descriptioncovering the walls and floor of the tank that elbow grease and a steel bristle brush would not clean up in ~2hrs of work. I wasn’t as interested in scraping through it as I was in cleaning out any spots of semi-permenantly attached dross.
From reading further on Google, looks like I’ll either be calling AVID to buy a new tank shortly or welding one up myself from sheet stock in an alternate material.
Well, AvidCNC should post care instructions for their tanks. They need to now as they have a customer who has been effected.
The only reason I knew about it was because of water cooled aircraft engines back in the 80s started having troubles as owners started using cheaper automotive antifreeze. One of those word of mouth things that ruined many engines.
There are several formulas for anti-rust, anti-dross and anti-splatter that are aluminum safe. They are very expensive.
If you remember back I was babbling about adding a 3,000 GPH recirculating pump and secondary storage tanks to my table, this very topic is what was driving all that.
I am sorry I didn’t mention this earlier 