Dont dose anything you cant test for ,good water changes with good salt add all the trace elements you need all you need to supply is great light and water changes and calcium and alkalinity additives to keep DKH up.
250 Se would be fine I run them on my 200 24" deep the par is about the same De VS Se when you slide the glass in front of the DEs that they must have.Do whatever you can get the cheapest both work great.