Metal stuff, plastics, and your tank...informational.

[Sk8r]

Saltwater is 'aggressive' when it comes to dissolving most metal. Titanic, eg, is dissolving in huge 'rustcicles'. It's taken this long for the salt water to really get at it, but it's changing fast.

On the other hand, the ship sank in 1912. And it's held up a century in saltwater.

Gold won't dissolve. It's a noble metal. Silver goes black and brittle after long submersion. But your rings are safe. Your copper bracelet---I'd take it off.

Copper is not immediately dangerous unless in solution. Anything with cupri- as a prefix is copper. Brass plumbing fittings are copper mixed with zinc. Bronze is copper mixed with tin or arsenic. Pewter is silver mixed with tin, or a variety of other metals including copper. So if it's a 'mixed metal' or copper--just treat it as a poison, and one that dissolves to harm fish and corals. Your losing a razor blade into the rockwork is not harmful, no big deal. Your guest tossing a penny into your tank to be funny is a serious problem, and that penny has to be gotten out if you have to move rock to get it.
Copper is used as a pesticide in the sense of removing parasites like ich, and some fish species tolerate it, but your sand bacteria, your inverts, your corals, and some fish species do not tolerate it and will die.

Lead is poisonous and is not a good thing in a tank.

Iron not so much: granulated ferric oxide (gfo) is used to absorb phosphate from a tank, to its benefit.

Steel or stainless steel will last longer than iron. But it too will rust over long exposure.

Aluminum is fairly resistant to salt water and not a great threat.

Always when considering whether something's safe in your tank, look at the screws and such. Is it all one kind of metal?

Do not use a brass connector between your ro/di water and the tank. One BEFORE the filter, eg, your house plumbing, is ok, because the ro/di will remove the contamination. Do not use a metal hose clamp where it's exposed to salt water: for one thing, it will fail.

Do not use volcanic rock, eg basalt, and others, in your tank: volcanic rocks tend to contain iron and magnesium, and other metals. Lava is a veritable soup of molten metals and assorted minerals. Limestone, which is composed of pure dead coral skeleton, pure calcium carbonate, is the rock of choice...and the holey-er the better [more surface area.]

If despite all precautions your child has flung your tv remote into the fish tank (what connection there is in the infant mind between tv, fish tank, and needing a remote, I cannot say---but they do it again and again) --- there is reason to get it out of there real fast. BATTERIES are metal. And not friendly metal either.

There is a product called PolyFilter, and I recommend having a packet of it. If you ever suspect contamination of various sorts, cut a small square and put it in the water flow. It turns color to tell you what it's picking up. And it WILL bind copper, eg. Read the instructions.

Is it ever safe to use metal tools IN the tank? Yes, if you have to. But be careful they don't have machine oil or the like. You can use a nipper, or a pair of pliers, no problem---they're steel, and you're not going to leave them in there. Be sure they're clean, then do the job. And to protect your tools, rinse them off in plain water to get the salt off, dry them and lay them, at full spread, on a towel, in the sunlight, which will assure no rust.

A small note on pipe and fittings: you can use any plastic pipe that's white, usable for drinking water. No metal. You can use most anything for a drain---if it's leaving your tank, and not coming back, any sort of pipe is ok.

Is your water safe sitting in plastic? There are arguments about that, but in general, a lot of us think you're fairly ok with two product names, polystyrene and Rubbermaid Brute. Poly is ok for salt mixing and general work. The Brute cans are used by many of us for topoff containers in basement-based sumps. I use one myself, and have an lps reef with no issues I've ever uncovered.

Hope that's helpful for you.

[dbl]

Great information and should probably be a sticky!

[dbl]

Sk8r...have a question regarding garden hoses? I use a white hose labeled as a "marine" hose to pump both SW for changes and RODI water to reservoir. Any idea if I'm playing Russian Roulette here? Haven't noticed any corrosion thus far on fittings? Your help is appreciated.

[toothybugs]

Both polyethylenes (HDPE and LDPE) should be good too. They're known for being inert.

[Sk8r]

I've never used a marine hose and have no idea what metal might be used for nozzle and coupling. Plastic would be safe. Stainless would be ok. Brass, definitely not.

Myself, I just use a plain length of hose (no coupling, no nozzle) bought from Ace Hardware, off a roll. If you use the right inner diameter, it usually will stay on the pump ok---my motto is 'if it's underwater when it leaks a little, it's no big deal.' So I don't hoseclamp things, but I may use a hairdryer to make a snug hose go on. They also make silly little plastic hoseclamps, which are good for killing your thumb, but which (for me) never seem to be that great at staying put.