I saw this tank article a while ago & considered it. You wouldn't want to use salt water because of spray and salt creep but it wouldn't be terrible hard to accomplish with an existing controller & ATO. Some PEX or PVC
plumbed into the end of the ATO pump with holes or channels would be enough.
The issue for me is timing. To make it really spectacular, I would've wanted a lot of rain, but my ATO kicks in for a few seconds an hour. I would have to change the program to only run the ATO a few times a day which would alter the stability in order to get the desired downpours. It's not a huge trade off, but one I didn't want to take. My ATO is also concentrated limewater which would have to change.
A nice design and bit of innovation for sure though. If you had a lot of mangroves, a similar scaled down system would be great too.