Aluminum

[ZoWhat]

I have 4 black box lights that I've built aluminum frames for them to perfectly sit in and to mount above the waterline exactly where I want.

Aluminum "L" struts came from HomeDepot

The aluminum frames are like 3 yrs old and have been noticing the aluminum is CAKEY...CHALKY on the surface but wipe down, wipe off

So I took all the frames into the garage, thoroughly cleaned them and spray painted then with Duplicolor CLEAR spray paint....like 4-5 thin coats.

QUESTION: how much of a chance do you think with the CHALKINESS on the frames I have Aluminum problems in my water column?

I know I know...do an ICP. but heard trace metal reading can be waaaaaaay off in these ICP tests

 

[Vinman]

I have 4 black box lights that I've built aluminum frames for to hang above the waterline exactly where I want.

Aluminum "L" struts came from HomeDepot

The aluminum frames are like 3 yrs old and have been noticing the aluminum is CAKEY...CHALKY on the surface but wipe down, wipe off

So I took all the frames into the garage, thoroughly cleaned them and spray painted then with Duplicolor CLEAR spray paint....like 4-5 thin coats.

QUESTION: how much of a chance do you think with the CHALKINESS on the frames I have Aluminum problems in my water column?

I know I know...do an ICP. but heard trace metal reading can be waaaaaaay off in these ICP tests

When you're lights are off(in the morning)feel the aluminium. Is it damp or wet from evaporation.

 

[ZoWhat]

When you're lights are off(in the morning)feel the aluminium. Is it damp or wet from evaporation.

Great question..idk. but I do have to clean the glass of the fixture once a month from salt creep and/or micro splashes that are on the fixture glass.

I think I know where this is going...

 

[ScottB]

I am familiar with the chalkiness you are describing, but I don't know whether that is leaching. Pressed to guess, I'd say it is leaching.

The presence of some metals is obviously a big deal, but Al often tests as present -- sometimes at high levels like you said -- but without much/any detectable consequence.

I just sent off my first ICP this week. I run a ton of Marine Pure block that is suspected to leach Al although my hard corals don't seem to care. I cannot keep ricordeas, but otherwise corals do well. We will see.

 

[AZMSGT]

That chalkyness is corrosion. It is aluminum returning to it’s original state. If it gets into your water I’m pretty certain it will raise AI metal in the system. To what level, I couldn’t be sure. Your saltwater is acting as an electrolyte and causing the reaction. If you have dissimilar metals touching each other and it’s getting wet the corrosion will be worse.

It’s best to use a primer made for aluminum and paint on the bare surface of aluminum to prevent corrosion. For 16 years I practiced hands on corrosion prevention on flying beer cans. Dealt with it allot.

 

[Nick D]

That chalkyness is corrosion. It is aluminum returning to it’s original state. If it gets into your water I’m pretty certain it will raise AI metal in the system. To what level, I couldn’t be sure. Your saltwater is acting as an electrolyte and causing the reaction. If you have dissimilar metals touching each other and it’s getting wet the corrosion will be worse.

It’s best to use a primer made for aluminum and paint on the bare surface of aluminum to prevent corrosion. For 16 years I practiced hands on corrosion prevention on flying beer cans. Dealt with it allot.

If the aluminum parts were from Home Depot, probably cheap from China. Be careful. Could be coated with some type of alum product but won’t hold up .