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Jaymeany
06-08-2006, 08:32 PM
SO i used these to attach my MH's since they are deck screws http://www.doityourself.com/invt/u744725#
If there is any signs of decoloration I replace the screw. Well I dropped one. What affect does steel and the Dicromate Finish have on saltwater, I can't find the screw in my tank. It may have bounced out but I'm not positive. Please help!:confused:

Krish
06-08-2006, 08:39 PM
I don't know how true it is, but I was once told that a rusted screw is basically phosban...I won't call the name of the person that told me that incase it isn't true, but hopefully for your sake it is so you don't have anything to worry. I wish you the best:)

wrightme43
06-08-2006, 09:13 PM
When the lights are out, use a bright pen light to find it. Use a magnet on a string to remove it.

Sk8r
06-08-2006, 09:15 PM
Your mag float magnet can often fish it out. Just make passes above and around your rockwork with half the magnet.

NaH2O
06-09-2006, 06:47 AM
Moving to the chemistry forum to find out the answer to this:


What affect does steel and the Dicromate Finish have on saltwater, I can't find the screw in my tank.

chrisdaphish
06-09-2006, 12:23 PM
sigh i JUST caught the pun.. im so stupid=P haha i may be "Screwed" screw...screwed.... *sigh=) anyways good luck geting it out!

Boomer
06-09-2006, 12:24 PM
Dichromate steel is fairly resistant in seawater, if it is yellow dichromate steel which is equal to 316ss. Was this screw yellow. All dichromate steels are resistant to corrosions with the yellow, due to zinc, being the best. The issue of steel is not the iron but things like chromium, zinc and other toxic metal ions. Many may just settle out or get bound up. But to be safe I would look for the screw but not get all wound up and loose sleep over it :D

Wright has be best suggestion, a magnet. Runing carbon will help has it removes these metal ions


Here is something to read

Reef Aquaria with Low Soluble Metals
http://www.reefkeeping.com/issues/2003-04/rhf/feature/index.php

Krish
06-09-2006, 01:16 PM
Boomer...Is there any truth to that statement that a rusted screw is basically phosban? Someone told me that and I was just curious...Thanks:)

Boomer
06-09-2006, 02:15 PM
No they are not the same. Rust, finall product is ferric oxide (Fe2O3). Stuff like Phosban is iron oxide hydroxide FeO(OH). However, there are middle reactions that produce iron hyroxide Fe(OH), still not iron oxide hyroxide

Fe → Fe2+ + 2e−

4e− + O2 + 2H2O → 4OH−

Fe2+ + 2OH− → **Fe(OH)2**

4Fe(OH)2 + O2 → 2(**Fe2O3**.xH2O) + 2H2O

Randy discusses it here in greater detail

Iron Oxide Hydroxide (GFO) Phosphate Binders
http://reefkeeping.com/issues/2004-11/rhf/index.htm

Krish
06-09-2006, 02:18 PM
Thanks Boomer:)

My2heartboys
06-10-2006, 04:14 PM
Dichromate steel is fairly resistant in seawater, if it is yellow dichromate steel which is equal to 316ss. Was this screw yellow. All dichromate steels are resistant to corrosions with the yellow, due to zinc, being the best. The issue of steel is not the iron but things like chromium, zinc and other toxic metal ions. Many may just settle out or get bound up. But to be safe I would look for the screw but not get all wound up and loose sleep over it :D

Wright has be best suggestion, a magnet. Runing carbon will help has it removes these metal ions


Here is something to read

Reef Aquaria with Low Soluble Metals
http://www.reefkeeping.com/issues/2003-04/rhf/feature/index.php
The other thing he could do is get a blue damsel and wait for it to find the screw and haul it out only to drop it right in front on the sand. :) Crazy damsels.

Anne