The bucket was destroyed and pieces of plastic "went flying into the pool".
Mr Mahy said he had been mixing pool chemicals for 12 years but the difference this time was he inadvertently used two chlorine tablets that had different acid compounds.
"I had some chlorine tablets for the pool and they weren't dissolving quick enough in the bucket, so I poured some granules in on top and it turns out, that even though they're both chlorine, they had a different acid compounds in it, and that's what reacted.
"I sung out to the missus to ring the ambulance, and then next minute, the fire brigade turns up."
With the aid of a neighbour and a nearby roadworker who were alerted by loud banging noises, he rinsed his eyes out with the garden hose before paramedics took him to Tauranga Hospital. Each eye was flushed out with a litre and a half of water.
"I only let that go on for half an hour 'till I said I couldn't handle it any more."
Fortunately, Mr Mahy had no scratching or damage to his eyes.
"You don't know until you get something in your eye how excruciating it can be."
He wanted to thank his neighbour and advised people to be careful with pool chemicals.
Mr Mahy would be going back into hospital next week for a cataract operation on his right eye.
"I had a go at doing it by myself, but it didn't work out. I won't be trying that again."