It’s a Cast-iron housing, so the housing is not corrosion free.
It just corrodes much slower, then a brass housing would, but it will leache out into your reservoir over time.
Question is if’s so little it don’t matter, only tried the brass housing and that messed my plants up fast. It might also be the coating protecting it, and once the coating is gone, it might corrode much faster.
Would be nice, if it’s just so slow it won’t harm the plants.
Fingers crossed for you, that would be really cool.