Is Stainless Steel Safe in the System????

[fiorano]

I have an friend in the refrigeration business building me a custon chiller. There are a couple of parts that will be stainless that will come in direct contact with the tank water. Is this OK? (I know to stay away from all other metals.)

[barbra]

No metal is okay for continuous contact. Stainless holds up better than others do, especially 6061T6, but salt is too corrosive and it is not safe over time.

[bertoni]

Some expensive grades of stainless steel are okay, and titanium is safe as well.

[rishma]

1. You need to determine which alloy your friend has. Stainless steel can mean many things.

2. 6061T6 is not steel at all. It is an age hardenable aluminum alloy. Not a good choice.

3. Titanium is essentially immune to corrosion in sea water at normal aquarium temperatures.



My guess is your friend will have 304 or 316 stainless steel. There is a big difference in seawater performance so you need to know. 304 is generally unsuitable except at temperatures below 10 C. 316 will do well at temperatures below 30C as long as you do not form a crevice. If you form a crevice, the 316 will not do well long term. In flowing airated sea water, I would not expect enough corrosion to notice any adverse affects on the tank unless you have a very large piece of metal or a very small water volume. I hope that helps.

You might do well just to order a Titanium coil from Aqualogic and have your friend build the chiller around that.