Typical and Potential Sources of Rust

[Punjab]

I'm always worried about excessive rust leaching from various pieces of equipment into my tank. I don't really ever measure for elevated levels of iron or heavy metals but I probably should. I also can't imagine that a corroding piece of steel leaching into the tank is a good thing.

There are the obvious places to check for rust like metal hose clamps and some pumps use steel screws to hold the impeller volute on. I finally switched to an all plastic/ceramic pump because of rusting steel screws.

Just today (and what got me thinking about making a thread) I noticed that the pvc gate valve I'm using on my skimmer outlet had a steel screw in the top that holds the valve handle on and it's completely rusting away. Leaching it's red rust right into my skimmer outlet.

So I'd like this thread to be a list of different places that you should check for leaching rust. Please feel free to chime in if you've found that something you've used for a long time suddenly developed rust.

 

[SkyShark]

I noticed a tunze magnet starting to rust/corrode in my tank.

 

[scchase]

GFO= rust. Same thing actually, as long as its pure iron and there arent any dangerous heavy metal impurities no problem

 

[that0neguy1126]

Like scott said it's not really an issue. Pretty much everything in your tank. Pumps, valves, etc will have something that can rust. If you really want to you could replace it all with stainless steel. While not impervious to rust, its a lot more resistant than regular steel.

 

[Punjab]

There is a huge difference between granular ferric oxide and a deteriorating screw. In addition to that, GFO hardly dissolves into the water column or comes into contact with corals. The common screw, even stainless steel, in saltwater will turn to fine particles and get spread throughout your tank.
Yes, GFO is iron rust, but it's not adversely increasing the levels of heavy metals in your tank. A rusty old screw is.

 

[that0neguy1126]

Not exactly true.

I am sure if you run GFO you rinse it out and see all those particles right? You really think you washed those all out with 5 gallons of water? or that none of it grinds and breaks off when you run water through a reactor? Also Iron and Iron Oxide bind fairly well with Carbon and would quickly be taken out of your water if you are running Carbon.

What heavy metals exactly do you think it would be leaching into your tank? Obviously you wouldn't find anything with copper. Zinc maybe, not sure of the effect it would have. Cadmium maybe? RHF has a really good article about the metals found in Calcium Oxide that many people dose with. http://www.advancedaquarist.com/2003/5/chemistry

On a side note, I've been diving off many wrecks where they are rusting pretty bad and never seen anything but healthy coral, sponge, and fish life on them. I understand the ocean is a much larger fish tank but one would expect if iron or iron oxide is bad that there would not be thriving ecosystems on these wrecks.

 

[Punjab]

Ha! Sounds good to me, breh. Let the metal rust away. Instead of GFO you should try loading your reactor up with rusted chunks of metal. It's the same thing right? No harm no foul. *This is me making the biggest eye roll you've ever seen

You're making some useless arguments. GFO equals rust but rust does not equal GFO. The fact that GAC removes it is also moot. Why let something leach into your tank just to use up your GAC when you could prevent it from getting into the tank in the first place? Natural seawater is balanced with trace amounts of many heavy metals. Excess iron and other impurities will absolutely create an imbalance to those amounts. An imbalance that will force you to perform more water changes to keep in check to keep your corals happy.

You're comparing to the ocean?! Give me a break. Random hardware rusting away not only degrades the integrity of that piece of hardware but it is also polluting your closed system.

 

[that0neguy1126]

Whoa, calm down buddy. We can have a civilized and educated conversation about this.

Actually chemically it is pretty much the same and will perform the same function. Just not quite as well as Iron Oxide Hydroxide which is technically what GFO is.

There is plenty of proof that rusting metals cause no issues in tanks. But there is also plenty of people claiming a small rusted washer crashed their tank. Which I find unlikely due to the amount of iron actually introduced into the tank.

Lets take a look at what it would take to add significant amounts of iron into a tank.

Let's take 100grams of Fe in a 50 gallon tank. Lets assume for math that we actually have 50 gallon of water. and it's pure H2O.
50 gallons would be 189271ml of water which = 189271g

so lets take our 100g of Fe divided by 189271g of water and multiple by a million.

thats roughly 528ppm of Fe.

So how much is 100g of Fe? Well 10 1/4 diameter 1" bolts would be about 90g.
So you would need to convert 10 bolts completely down to rust in order to add a concentration of 528ppm of iron into a 50 gallon tank.

There is more iron being added by your salt mix each week as well as the food you feed your fish every day then the amount of rust coming from a rusting bolt.

and iron itself is actually not toxic to anything in your aquarium. It is used in the growth of many plants which we think would cause an excess of algae growth in our tanks. When in reality algae growth is more commonly limited by the amount of phosphates in the water than the amount of available iron.

Is it worth swapping out rusting equipment? sure why not, part of our regular maintenance. Is leaving a rusting bolt in your tank going to cause any harmful side effects? chances are that it will not.

 

[Punjab]

This is laughable. You go ahead and load your tank up with a handful of 1/4" bolts, get your dissolved iron levels up to 528ppm and let me know how things are working out for you in a year.

Iron in natural seawater is measured in parts per trillion and at its most concentrated is found around 2 parts per billion. This thread isn't about tank crashes or whether or not iron is toxic. It's about adding iron to your tank unintentionally, or even unknowingly.

You and scchase are under the impression that all rust is created equal. It is not. Rust does not equal GFO just because GFO equals rust.

Assuming the hardware we're referring to is pure iron (which it never is) then odds are you're not introducing excessive levels into your tank with a single rusty screw. Yet, that is completely relative and relies on the size of the system it's rustng away in.

Honestly, I could care less at this point. You've successfully derailed this thread before it ever even got started. Have a great weekend, breh!

 

[scchase]

Sorry but I have read the chemists response to this subject and I will go with them, I don't know why you are being so agggresive on the issue.

 

[reef dummy]

This is laughable. You go ahead and load your tank up with a handful of 1/4" bolts, get your dissolved iron levels up to 528ppm and let me know how things are working out for you in a year.

Iron in natural seawater is measured in parts per trillion and at its most concentrated is found around 2 parts per billion. This thread isn't about tank crashes or whether or not iron is toxic. It's about adding iron to your tank unintentionally, or even unknowingly.

You and scchase are under the impression that all rust is created equal. It is not. Rust does not equal GFO just because GFO equals rust.

Assuming the hardware we're referring to is pure iron (which it never is) then odds are you're not introducing excessive levels into your tank with a single rusty screw. Yet, that is completely relative and relies on the size of the system it's rustng away in.

Honestly, I could care less at this point. You've successfully derailed this thread before it ever even got started. Have a great weekend, breh!

FWIW, A metal scraper accidentally dropped in my tank and i didn't notice it for a few days. It was rusting like crazy and did no harm to a 120g tank.

 

[DJBM3]

I also caught my Tunze ATO magnet rusting... I sealed it up with silicone and have not seen an issue since.

 

[that0neguy1126]

I don't know why you are being so defensive about this topic.

I never said 528ppm was good for a fish tank. That number is to show you how much iron would have to rust to create that level. Yes, NSW is about 3.4 ppb

I know exactly what this thread was created for, and I am questioning you on why it matters or how much harm it actually does.

Actually Fe(OH)3 is Fe(OH)3 regardless of where it came from or what label you put on it.The atoms in the iron and iron oxide don't care what you call them, they still bind the same way I am curious what impurities you think are in these bolts and what else they would be leaching? Zinc? Its more corrosive resistant than steel. . The point I am trying to make is that so little rust is being taken off of that screw or bolt that it does not affect your tank. You introduce 100x more of iron or any other metal through salt changes and feeding every week then what is introduced by a screw rusting.

Another key fact that I haven't mention is iron is actually very insoluble in water at 8.2PH. Most any iron introduced into a aquarium just sinks to the bottom.

As for observable results. I have had 2 nuts keeping my water level sensors on my tank for years. There is a small amount of rust on them which I am sure every now and then gets introduced into the tank. I should take these nuts off an weight them to see how much exactly has been lost. I can tell you though the last time I tested for Iron levels in my tank it was either at or below the lowest measurement possible of .05ppm