Aluminum Water Tanks

[Golden Echo]

Our boat has 2 thirty-five gallon aluminum water tanks. We know aluminum is not good. But we are stuck with them for a while. The problem we're having is some thing is growing on the walls of the tanks. These things look like rocks surrounded by a white kind of fur. It looks almost like mold suspended in the water on the walls of the tanks. This material wreaks havoc on the pumps and is a pain to clean off. Q: What is it? And how can I get rid of it? Anyone out there had a similar problem? GE

[jannw]

Ohhhh ... I got this one!

It's Aluminium oxide ... my Aluminium boat with Aluminium water tanks gets this if they haven't been cleaned (like a few months ago when I bought it). To be honest my Aluminium Moka pot coffee maker also gets it if I leave it uncleaned for a few days.

You clean it off by hand, with a scrubbing brush, and curse the B@$tard who let it happen ... and you keep the tanks clean in future (Although I'm not quite sure how to do that exactly ... I think a good start is not leaving them for long periods half full of water)

You need to fit a strainer between the tanks and the water pump to catch the big gunk that you couldn't reach when you cleaned the tanks ... it looks like this: https://www.google.co.uk/search?q=wa...w=1280&bih=675

and you also need to fit a charcoal water filter before your drinking water tap.

The jury is out as to whether Aluminium Oxide has negative health effects ... there has been some links to altzheimers, but it is unproven. See : Talk:Aluminium oxide - Wikipedia, the free encyclopedia and http://www.alueurope.eu/wp-content/u...0728-final.pdf

When I asked the chandlery if they had a special magic aluminium tank cleaning solution, they gave me very expensive Hydrochloric Acid which had been mixed with something to make it into a gel. I had problems applying it, and had timing issues, so I can't say how well it would work ... but next time if I have time on my hands I will drain the tanks and spray them down with a dilute solution of HCl, and watch and wait (always well vented ... Acid + metal = salt + water + hydrogen if you remember your chemistry!)

Good luck. I'm still pulling bits of Alu Oxide out of the strainer months later.

[s/v Beth]

If you put HCl on aluminum you may dissolve the tank. Just FYI....

[Hud3]

GE,

Take a look at this thread--it might help answer your questions.

http://www.cruisersforum.com/forums/...ion-42678.html

There are other threads on the topic that you can find using the Google search (click the link in my sig line, or use the "Search" pull-down menu, top-right on the page).

[belizesailor]

Originally Posted by Golden Echo

...We know aluminum is not good. But we are stuck with them for a while. ...

Aluminum water tanks are not necessarily a bad thing. Whether or not they develop problems depends a lot on the specific alloy used to make them, what chemicals they are exposed to, and how they are installed.

They ARE fundamentally a bad idea for waste holding tanks, but can work out fine for fresh water and fuel. When I sold my previous boat, the aluminium water and fuel tanks were almost 20 years old and still in very good condition.

[Doug Brown]

Hi - a word of caution. I would not drink fresh water than came from a aluminum tank that had been cleaned with HCl...

If - or more likely - when you get pin hole leaks in the aluminum tank, the easiest way to cure the problem is to make an access hole on either the top or a side so you can gain complete access to the tank interior. ID and save the piece you have carefully cut out of the tank so you can use it as a pattern for a patch

Carefully sand the tank down by hand to knock off the big deposits. Wipe down or flush the tanks to remove sanding and deposit dust.

Then coat the entire interior surface of the tank with Henry's Coal Tar by using a long handled paint brush. It goes on sort of like real thick paint and is pretty messy - so wear gloves and a moon suit top with long sleeves.

Henry's is FDA approved for coating water tanks. It's thick enough that it plugs holes, and it insulates the aluminum (or stainless) to prevent further corrosion. It gives fresh water a "sweet taste".

I've used it on fiberglass, aluminum and stainless steel tanks and it works great. I use to repair a lot of SS water tanks on Peterson 44's that had holes in them - way cheaper and quicker than tearing apart a boat to get the tanks out!

Happy cleaning!

[Astral Blue]

Aluminum oxide related issues are the least of your concerns with having aluminum tanks. Aluminum does not belong in the human body; and using these tanks for potable water for drinking and bathing can lead to serious neurological damage. Aluminum has been linked to Alzheimer's disease and the dementia that follows it. Here are some articles for reference:

Can Aluminum Cause Alzheimer's Disease? by Melvyn R. Werbach, M.D. Senile dementia is a progressive degenerative brain disease associated with old age. Its symptoms include short-term memory loss, slowness in thought and movement, confusion, disorien

Aluminum hydroxide

Aluminum in the Diet and Alzheimer’s disease

10 Tips to Help Naturally Prevent Alzheimer

If replacing these tanks is not an option, consider installing a bladder type liner.

[Golden Echo]

Well these are all great comments. Ever since we noticed the geology growing in the tanks we no longer drink the water. We use it for dishes and cleaning. The plan is to replace the tanks with SS when we get around to painting the inside of the boat ( steel hull). I know there may be galvanic problems with the steel but the tanks are encapsulated in foam and bedded between the stringers. We'll have to gut the interior to paint so we'll do it then. Thanks. GE

[callmecrazy]

This is definitely a job for Brew Coat, from Sound Specialty coatings.

Forget replacing the tanks, unless you really enjoy spending money... just give them a few coats of this stuff and forget about it for another 30 years.

[Astral Blue]

Originally Posted by callmecrazy

This is definitely a job for Brew Coat, from Sound Specialty coatings.

Forget replacing the tanks, unless you really enjoy spending money... just give them a few coats of this stuff and forget about it for another 30 years.

I doubt this coating will adhere to aluminum unless the surface is chemically etched with zinc chromate or a similar product. Zinc chromate is highly toxic and is not approved for use in potable water applications. There is no food-grade product that adheres to aluminum that I know of.

A bladder insert would (in my opinion) be the most cost effective and safest solution. Consider these tanks:

PLASTIMO Flexible Water Tanks at West Marine

[DeepFrz]

Encapsulating metal tanks in foam, any metal, is a sure way to kill them early. The foam will trap any water that gets in, it will sooner or later, and corrosion will destroy the tanks from the outside. Metal tanks need to be mounted on strips of UHDP or something similar sealed to the tank so that no moisture can get trapped between the UHDP and the tank walls.

[Hiracer]

100% hydrogen peroxide is used as jet fuel. It can be stored in aluminum tanks. Food grade H2O2 (40%) can be diluted down to 1 or 2 percent in your tanks to kill everything. H2O2 is a great biocide, and it degrades into oxygen and water so it's safe for the environment. Be sure to use eye protection when using food grade hydrogen peroxide (I used my diving mask). I have used H2O2 for years on my aluminum tanks and it works marvelously.

[colemj]

Originally Posted by Astral Blue

Aluminum oxide related issues are the least of your concerns with having aluminum tanks. Aluminum does not belong in the human body; and using these tanks for potable water for drinking and bathing can lead to serious neurological damage. Aluminum has been linked to Alzheimer's disease and the dementia that follows it. Here are some articles for reference:

Can Aluminum Cause Alzheimer's Disease? by Melvyn R. Werbach, M.D. Senile dementia is a progressive degenerative brain disease associated with old age. Its symptoms include short-term memory loss, slowness in thought and movement, confusion, disorien

Aluminum hydroxide

Aluminum in the Diet and Alzheimer’s disease

10 Tips to Help Naturally Prevent Alzheimer

If replacing these tanks is not an option, consider installing a bladder type liner.

The relationship of aluminum to Alzheimer's and other diseases was scientifically debunked a while ago. By real scientists.

Conflating issues with aluminum vaccine adjuvants with aluminum storage containers is like conflating the lethality of lead bullets prejudicially inserted in your abdomen with drinking out of leaded crystal. Your citation on that is useless to this discussion.

The citation by Frisardi discusses that while some studies hypothesize a link, none of them satisfy the criteria for causation.

Your other links are from anti-vaccine fearmongering and the like.

Aluminum is one of the most abundant elements on earth and it is impossible to not ingest it daily - it is in everything.

There is no problem drinking water stored in aluminum or eating food prepared with aluminum cookware. There can be a problem drinking certain things out of aluminum cans, but that is not the fault of aluminum.

Mark

[colemj]

Originally Posted by Hiracer

100% hydrogen peroxide is used as jet fuel. It can be stored in aluminum tanks. Food grade H2O2 (40%) can be diluted down to 1 or 2 percent in your tanks to kill everything. H2O2 is a great biocide, and it degrades into oxygen and water so it's safe for the environment. Be sure to use eye protection when using food grade hydrogen peroxide (I used my diving mask). I have used H2O2 for years on my aluminum tanks and it works marvelously.

Everything you say is true for a biocide, but will not help with the formation of aluminum hydroxide, aluminum oxide or aluminum chloride - which is the OP's issue.

Mark

[colemj]

Originally Posted by Golden Echo

Our boat has 2 thirty-five gallon aluminum water tanks. We know aluminum is not good. But we are stuck with them for a while. The problem we're having is some thing is growing on the walls of the tanks. These things look like rocks surrounded by a white kind of fur. It looks almost like mold suspended in the water on the walls of the tanks. This material wreaks havoc on the pumps and is a pain to clean off. Q: What is it? And how can I get rid of it? Anyone out there had a similar problem? GE

You are experiencing aluminum hydroxide, and probably a bit of aluminum oxide and aluminum chloride. These won't cause you any health problems but, as you noted, they can clog a pump.

Best thing to do is to filter your water going into the tank through a carbon filter (buy a cheap house filter and make a hose attachment for it), and put an inexpensive screen filter housing on the pump intake line in an easy accessible spot. Groco, Shurflo and Jabsco all sell them, and most of them include one with the pump. The screen will capture these as they come through, and if you mounted it in an easy access place it will be a 30 second job to check and clean as needed.

Mark