Grieving man shares warning after a normal day at the beach leads to his dog's death.

​A day at the beach was nothing out of the ordinary for 29-year-old student Chris Taylor and his six-year-old dog.

But last week, a run along the bay led to the freak death of the Florida man’s beloved Labrador Retriever.

The two spent Monday at a Florida dog beach where O.G. loved to swim and play. That night, there were already signs something wasn’t quite right.

O.G. looked unstable on his feet and began to have issues with diarrhoea and vomiting. Mr Taylor put it down to exhaustion after their active afternoon, and thought a little rest would cure him.

Mr Taylor told local news station WFLA he continued to keep a close eye on O.G. throughout Tuesday and he seemed to be a little better. He was still lethargic, but eating and drinking small amounts.

Then on Wednesday, O.G.’s condition drastically worsened. He stopped eating and wasn’t responsive. He appeared to be dazed, staring blankly into a corner. Fearing the worst, Mr Taylor rushed his dog to the vet.

That's when O.G. got his crushing diagnosis: he was slowly dying from salt poisoning after drinking too much seawater. It was too late to save him. The dog was seriously dehydrated and the swelling in his brain had caused permanent damage. He had to be put down.

"He was convulsing, and I asked if he was in pain, she (the vet) said 'I don't even think he knows where he is'," he told WFLA.

Mr Taylor told Fox13 he had no idea how toxic saltwater could be to animals. He is now determined to share his story to save other dogs and prevent owners from going through similar heartbreak.

"It still feels surreal... It doesn't feel like reality. I [have] to get a grip on that and realise that it is real and he's gone," he said.

Pets can get salt poisoning from ingesting large amounts of saltwater. This is what happened to O.G., who accidentally consumed too much while playing in the water, even though he'd been to the beach many times before without any issues.

Salt poisoning in dogs and cats can result in vomiting, diarrhoea, low appetite, lethargy,  wobbly walking, abnormal fluid accumulation within the body, excessive thirst or urination, potential kidney injury, tremors, seizures, coma, and even death when untreated.

Experienced veterinarian Dr Katy Meyer told WFLA many pet owners didn't realise the severity of the illness, particularly as symptoms can come on gradually.

Dr Meyer advises trips to the beach are limited to two hours, with breaks every 30 minutes and plenty of fresh water to drink.

If salt poisoning is suspected, dog owners are advised to act promptly.

A call or visit to your vet can save your pet's life. Treatment can include administering IV fluids, monitoring electrolytes, and treating dehydration and brain swelling.