I'm sorry Rico has been poorly and understand your concern for him.
It sounds likely he has an upset stomach brought on by the sand or sea water ingested.
While both can pose dangers, they need to be eaten in significant quantities to do so. A small amount of sea water should not cause salt toxicity and a small amount of sand should not cause an impaction or obstruction.
While the pink is a concern, it may simply be due to the inflammation caused by the previous vomits, making the food pipe and stomach more prone to bleeding a little.
Having said the above, as there is a risk of toxicity and/or impaction, we do need to be cautious.
If he continues to vomit, there is more blood brought up, he becomes bloated or he seems lethargic or has pale gums, I'd want him seen right away.
Otherwise, offer regular drinks of water and rehydration solution like Oralade if you have any.
Starve him for now but offer a small meal of chicken and rice in the morning. If he holds it down, offer the same a few hours later and continue to offer it for 24 hours. He should improve quickly.
If he cannot hold the food down or seems poorly, a vet check is important.
He may well benefit from some anti nausea medicine and antacids.