So..14 year old spa pool (cheaper brand when bought).   Been nursing it along with replacement parts over the last few years.. It's had various leaks over the years - new pumps and a few PVC joint leaks etc.  Main board is watertight - also had a new heater about 2 years ago.   Hadn't used it for a good few months - I have simple silver in it - which takes care of the bulk of water quality.  Opened it up and had a bad leak somewhere as about 300l of water was missing. It was half empty. Lo-flo on the heater had kicked in to protect it etc.  

Found the leaking PVC joint - fixed it, refilled pool, shock chlorinated and left for a few days. Went to check on it yesterday/ test water quality etc.  Convinced i got a shock from touching the pool water. Didn't plan on touching it again to check. 

Was insulated / wearing thick trainers but definitely that horrible sharp thud in end of fingertips. Left it overnight. 

Got voltmeter out today, stuck tip of positive lead in water and black to ground - literally the concrete pad.

The water is sitting at roughly .5v AC constantly. When i run one pump it rises to around 1v AC and running 2 pumps it goes upto 1.8v AC.  

Turned off spa at wall switch and 0v in the water so something leaking current in the spa system.

I am sure one of the main jet pumps has also been leaking - or has been leaked upon from a pipe above as there are white mineral crystals beneath it - where the water leak has evaporated. 

I ain't planning on doing any live entry tests and am wary enough around electricity so won't be probing much further.  

Sparkie or new spa pool time ?

Any guesses as to what is happening / happened thanks.  

Thanks for your thoughts

Ged