There's no such thing as Stainless Screws ??????

While, Stainless Steel screws are not entirely immune to rust they are much more resistant to rust than other forms of steel. Also, a piece of stainless steel that is partially submerged will be more prone to rust than a piece that is completely submerged.

 

Bottom line though is that I see no reason iron oxide to be the source of any trouble. You can dose iron for better macro growth. GFO is iron oxide. Not so sure what harm iron is going to do.

 

I don't think even having a piece of iron in the tank (even rusting) would matter. Not sure what harm a metal screw would do? As Powerman said, GFO is iron oxide.

 

when in doubt run a thin layer of silicone on the exposed part and it should be fine.

Personally i try to avoid them when possible.
i did use SS screws on my DIY freshwater canopy though. Although its not submerged it does tend to get quite moist. So far there is no rust to be seen however.

 

Get plastic screws?

 

Now that is a useful and practical solution for those who are paranoid.

 

Dude, have your LFS guy check this out;
Search: stainless

 

I know that A20 Stainless is sold as a lifetime marine grade steel alloy. It's used in marine applications all the time... even many acids don't hurt it. You can buy A20 bolts and screws from McMaster-Carr and any bolt specialty shop... probably not home depot. If you have a marine boat supplier try them also.

Always be suspicious of anyone who says "such-and-such" doesn't exist... they usually just don't know about it. (One known exception: free lunch)

 

absolutely are stainless steel screws etc...out there,i think what your teacher is referring to are the different grades of stainless steel, some arent suitable for saltwater applications at all and are more dangerous than normal steel, basically if a stainless screw or whatever is magnetic you dont want it anywhere near your tank

 

316 S.S is the only S.S you can have in direct contact with Saltwater . I have them all over my systems for corals and I hate coralline I bet your teacher a dollar to a donut I can send him some S.S screws that will never be harmed by Saltwater.. No radiator clamp is 316 and none I ever saw had a S.S any type of grade worm gear .