# cleaning aluminum water tank



## TSOJOURNER (Dec 16, 1999)

I recently purchased 78 sailboat with aluminum water holding tank. Tank is impossible to remove without substantial cutting of fiberglass under salon couch. Any solutions to thoroughly clean this tank? I have removed all existing water lines, etc. but the tank is my big problem.


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## GordMay (Dec 19, 2002)

What are you trying to clean off the Aluminum Water Tank? 

Aluminum reacts with air to grow its own oxide coating very fast. This hard, dark gray coating protects the metal. It''s found on all bare aluminum surfaces, including Water Tanks, which, if rubbed, leaves a dark gray mark. If washed off the of the metal, it quickly forms again. It presents no majorhealth hazrd, if left un-disturbed.

There are five categories of aluminum cleaners: 

1. Mild Soaps and Non-etching Detergents: Non-ionic detergent such as "Joy" 
a. If a mild soap or detergent is gentle enough o be applied with bare hands, it can be safely used on aluminum without spot testing first.
b. Automatic dishwasher detergents should be always spot tested first. Some of these detergents can discolor non-finished and anodized aluminum and can even bleach painted aluminum.
c. Non-etching cleaners are acidic or alkaline solutions containing inhibitors that permit the cleaning of the metal without etching. Care should be exercised in their use.

2. Solvent and Emulsion Cleaners:
a. These cleaners are relatively mild solutions which can be used for removing dirt and stains that cannot be removed by milder cleaners.
b. They generally can be used on bare, anodized, conversion coatings, and porcelain finished aluminum without spot tests, but product directions should always be followed exactly.

3. Abrasive Cleaners:
a. These include polishes, cleaners, cleaner polishes, wax cleaners, scouring powders, metal brighteners that contain abrasive particles, and may also include water, oil, wax, silicones, soap, acids or alkali.
b. These cleaners depend on vigorous rubbing action along with a chemical reaction, and can remove most dirt, stains, and corrosion products from aluminum and will restore most weathered aluminum surfaces.
c. They are rated as moderate and heavy-duty. Abrasive cleaners also include etching cleaners, and special heavy-duty cleaners.
d. Household cleaners with coarse abrasives should ONLY be used on aluminum with PORCELAIN FINISHES. Even a very fine abrasive can dull or scratch a highly polished aluminum finish. Fine pumice powder and stainless steel wool (grades 0000 to 00) can be used with these cleaners, but regular steel wool may leave rust stains.

4. Etching Cleaners: Try "AC-266" (Sherwin-Williams), or "Van Glo" (BASF-Wyandotte Corporation)

5. Special Duty Cleaners: Try "Sure Klean Aluminum Cleaner" (ProSoCo, Inc.).
a. These cleaners should remove aluminum oxidation, atmospheric dirt and carbon, and other surface stains from all types of aluminum surfaces.
b. Domestic soap flakes
c. Acrylate emulsion polish

From Alconox: http://metal-cleaning.alconox.com/cleaning_aluminum.htm

Alconox®
Concentrated, anionic detergent for manual and ultrasonic cleaning. Free rinsing to give you reliable results without interfering residues. Ideal for cleaning contaminants from glassware, metals, plastic, ceramic, porcelain, rubber and fiberglass. Excellent replacement for corrosive acids and hazardous solvents. USDA authorized. Dilute 1:100. pH 9.5 

Liquinox®
Concentrated, anionic liquid detergent for manual and ultrasonic cleaning. Free rinsing to yield reliable results with no interfering residues. Extremely mild and completely soluble in hard and soft water. USDA authorized. Dilute 1:100. pH 8.5 

Citranox®
Phosphate free, concentrated cleaner and metal brightener for high performance removal of metal oxides, scale, salts and inorganic residues in manual and ultrasonic cleaning. Corrosion inhibited and free rinsing for reliable results and no interfering residues. Ideal for trace metal analysis. USDA authorized. Dilute 2:100. pH 2.5 

LUMINOX ®
A low foaming, neutral pH detergent for use in manual, ultrasonic, and machine cleaning. This safe-handling detergent can be used for non-corrosive cleaning without chelation or alkalinity waste treatment problems. Recommended for cleaning aluminum and soft metal, alkaline sensitive labware, and medical instruments in aluminum trays. Luminox is free rinsing to eliminate interfering residues.

HTH
Gord


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## TSOJOURNER (Dec 16, 1999)

I am trying to clean the inside of the tank. Boat has been sitting idle for about a year and there is no telling what has grown inside of the tank.


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## GordMay (Dec 19, 2002)

I understand that you intend to perform a “prophylactic” cleansing on your Aluminum Water Tank. Subject to the following cautions, a Chlorine Bleach soaking should suffice to disinfect your tanks. The chlorine will kill any mold, and most bacteria - but only a manual scrubbing will remove the scum (and dead mold carcases). Hope you''ve got an access panel...

Long-term exposure to Chlorine is not recommended for any metal, Aluminum & Stainless Steel included.

Notwithstanding, it should be OK to shock-treat your tanks with Chlorine, provided you rinse very well after.

Despite being high in the Reactivity series, aluminum is resistant to corrosion because of the thin layer of aluminum oxide (Al2O3) which forms on its surface in air.
The oxide layer protects the metal beneath and renders it inert to any further reaction.

The thin oxide layer will react with an acid or alkali to form the corresponding aluminum salt + water. The exposed aluminum metal will then further react with acid or alkali to form the aluminum salt + hydrogen.

For this reason, aluminum cookware, water tanks (etc.) should not be allowed to come into prolonged contact with citrus fruits or vinegar (acids), or alkali cleaners such as caustic soda (sodium hydroxide).

As with the other elements, aluminum is absorbed and accumulated in the body, and has been linked to serious illnesses including osteoporosis, extreme nervousness, anemia, headache, decreased liver and kidney function, forgetfulness, speech disturbances and memory loss (Alzheimer’s). 

Aluminum and chlorine do not react rapidly at room temperature, but if the aluminum is heated, the reaction is vigorous. The product is aluminum chloride, a white powder that fumes in air, reacting with water to form HCl gas and aluminum oxide. 
Chlorine gas is poisonous and a very strong irritant. Inhalation of chlorine should be avoided. The reaction is sufficiently exothermic that some chlorine and aluminum chloride dust may be formed in the tank, so proper ventilation is necessary. Anhydrous aluminum chloride reacts violently and exothermically with water, forming hydrogen chloride, which is an irritant. Inhalation of aluminum chloride dust can irritate or burn mucous membranes.

HTH
Gord


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## Bermuda (Jan 30, 2001)

Personally I would never use any cholorine product of any kind in an aluminum tank. Again, this is just IMHO, but you are much better off and doing your tank a much better service if you use and industrial strength food grade Hydrogen Peroxide. I believe the concentration I have used in the past has been around 35% but if you take my advice then I recommend that you be very careful with it because although at that strength wont have the effect on your tank that chlorine will it can have serious effect on your skin.

Capt Bruce
boatskipper.com


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## RichH (Jul 10, 2000)

If you have access to a ''technical water'' company .... one who specializes in Reverse Osmosis or Ultrafiltration Membranes ---- "US Filter", Minntech, or similar local firms, see if they wont sell you some "Peracetic Acid". Peracetic Acid diluted to a 1% concentration will kill just about everything inside your tankage within a few hours --- but wont dissolve all the debris so you''ll have to periodically add some ''disinfectant'' to retard new critters from eating all the ''old dead bodies'' that remain. Peracetic wont be aggressive vs. aluminum as would Chlorinated mixes. 
1/2 gal. of peracetic diluted per 50 gallons of tank water should do the trick .... and with minimal ''damage'' to the aluminum but any acid will dissolve ''some'' of the aluminum. The solution can be dumped directlly overboard when done soaking .... or simply dump a few boxes of bicarbonate of soda into the bilge, etc. and mix there to neutralize before discharging. Obviously you will have to thoroughly and repeatedly rinse the tank until all is totally diluted out. 
Obviously the usual ''chemical safety warnings'' apply: heavy rubber gloves, chemical goggles, vinyl apron, knowledge, etc.


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## RichH (Jul 10, 2000)

35% hydrogen peroxide is extremely dangerous for a non-chemist to use. 
Buy your peroxide from a drugstore (~5%) ... much safer and wont make things go BOOM. 
;-)


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## sorcerer33 (Jun 25, 2007)

*cleaning aluminum tank additional question*

My 1993 boat has aluminum water tanks. There is so much aluminum oxide debris in the water that it clogs a screen before it gets to a water filter I would like to use. One owner says he just flushes the tank burning out one water pump per season. The tank has multiple baffles making only a small area accessible to scrub through an access port. I'm hoping there is a better way than burning out my pump! I guess I will be doing a lot of siphoning before I launch this year!


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## xort (Aug 4, 2006)

something else isn't right.

I have 30 year old alum. water tank. I check the screen in the pre-filter and it needs cleaning about once a month.


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## sailingdog (Mar 19, 2006)

Sorcerer—

How heavily chlorinated is the water in your area? Chlorine can cause an aluminum tank to deteriorate like that... and it sounds like you're in an area that uses fairly heavy chlorination as part of the water treatment.


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## sorcerer33 (Jun 25, 2007)

*Chlorinated water in aluminum tank*

SailingDog: The area I'm in has a previous owner who told me he had flushed the tanks of my boat and left bleach in the tanks to shock them. He succeeded in shocking me too. I'm afraid this was his way of freshening up his tanks - a method that I will not be using in the future.


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## sailingdog (Mar 19, 2006)

Properly used, chlorine bleach is perfectly safe for shock treating aluminum water tanks. It does have to be thoroughly rinsed from the tanks after doing so. It does not sound like the PO was doing that properly. Some municipalities use enough chlorine in their drinking water treatment to be a problem as well. That would just compound the problem of shock treating the tanks.


sorcerer33 said:


> SailingDog: The area I'm in has a previous owner who told me he had flushed the tanks of my boat and left bleach in the tanks to shock them. He succeeded in shocking me too. I'm afraid this was his way of freshening up his tanks - a method that I will not be using in the future.


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## Deadeye (Jan 8, 2009)

You mentioned thorough cleaning because you couldn't get the tank out to replace it. Just a thought, but if you can access the top of the tank, you could cut an access opening and use the tank to support and protect a bladder.

Sealing it with epoxy is another option, but I don't have enough personal experience with that to comment on it. West System has some water tank info on their site and their info on other epoxy applications is pretty good.


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## CapitanDon (Jun 27, 2010)

*aluminum tanks*

I just had my aluminum hull cutter in the yard for bottom paint and zincs and was told by the yard manager they had an aluminum hull NOAA vessel in for hull repairs that had integral aluminum freshwater tanks. I was told that when calcium deposits cut off the oxygen to the metal it begins to corrode as happened to this vessel resulting in major repairs to the hull.
I pulled the inspection plate on my integral freshwater tank after hearing this and discovered (to my horror) what looked like seaweed in the tank. apparently when this boat was built or re-fit, a coating was sprayed inside the tank to possibly prevent calcium deposit build up??. I have owned the boat several years (A custom build, I am the 4th owner) and have been occasionally adding a cup or so of household bleach to the water to kill any bacteria. (big mistake!) Apparently the bleach dissolved most of the coating leaving quite a mess in the tank as well as some minor pitting of the tank walls. So I have a similar (or worse) situation. My tank also cannot be removed. To clean it will be difficult due to baffels and the only access is the inspection plate (about 18" X 24"). Going in through the outside hull is also near impossible due to an encapsulated concrete filled ballast keel. (the tank is 40Gal centerlined amidships) The only way I see to access it is by removing the cabin sole above the tank (nicely done teak & cherry) Then I think the best option is sand or soda blast to clean and remove the pitting. From what I have learned as long as oxygen is present and calcium not allowed to build up the tank will last. 
I also admit to not being an expert in electrollisis (I cant even spell it!) and corrosion in aluminum before buying a boat with aluminum tankage.

Any advise or suggestions would be appreciated.


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## sailingdog (Mar 19, 2006)

While you'd be better off starting your own thread... *I'd point out that adding chlorine bleach to your water system on a regular basis is a really bad idea if you have an aluminum tank...* I would highly recommend discontinuing the practice. Chlorine bleach attacks the aluminum.

Cutting open the tank and replacing it with flexible bladder or a custom plastic tank might be better options than trying to clean and restore this tank. Without knowing how serious the pitting is, there is no way to see how severe the damage to the tank is, and trying to salvage the tank may just increase your costs overall.



CapitanDon said:


> I just had my aluminum hull cutter in the yard for bottom paint and zincs and was told by the yard manager they had an aluminum hull NOAA vessel in for hull repairs that had integral aluminum freshwater tanks. I was told that when calcium deposits cut off the oxygen to the metal it begins to corrode as happened to this vessel resulting in major repairs to the hull.
> I pulled the inspection plate on my integral freshwater tank after hearing this and discovered (to my horror) what looked like seaweed in the tank. apparently when this boat was built or re-fit, a coating was sprayed inside the tank to possibly prevent calcium deposit build up??. I have owned the boat several years (A custom build, I am the 4th owner) and have been occasionally adding a cup or so of household bleach to the water to kill any bacteria. (big mistake!) Apparently the bleach dissolved most of the coating leaving quite a mess in the tank as well as some minor pitting of the tank walls. So I have a similar (or worse) situation. My tank also cannot be removed. To clean it will be difficult due to baffels and the only access is the inspection plate (about 18" X 24"). Going in through the outside hull is also near impossible due to an encapsulated concrete filled ballast keel. (the tank is 40Gal centerlined amidships) The only way I see to access it is by removing the cabin sole above the tank (nicely done teak & cherry) Then I think the best option is sand or soda blast to clean and remove the pitting. From what I have learned as long as oxygen is present and calcium not allowed to build up the tank will last.
> I also admit to not being an expert in electrollisis (I cant even spell it!) and corrosion in aluminum before buying a boat with aluminum tankage.
> 
> Any advise or suggestions would be appreciated.


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## Snboard976 (Aug 10, 2008)

I wonder if I'm looking at aluminum oxide or calcium deposits in my aluminum tank? Removing the tank is not an option - teak & holly floor would have to be removed as well as sink cabinetry etc. Baffles in the tank make installation of a liner or bladder near impossible. I was told by someone with a knowledge of chemistry to use the product that is placed in a shower and sprays automatically to kill mold. He also said hot water was the best wash to use.


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## sailingdog (Mar 19, 2006)

What do the deposits look like? Aluminum oxide is usually a greyish color... but tends not to form except as a layer coating the metal. If the deposits are collecting, it is likely aluminum chloride instead, which is often a whitish powder.

Many of the products that are used to kill mold/mildew are not safe for use in potable water systems.



Snboard976 said:


> I wonder if I'm looking at aluminum oxide or calcium deposits in my aluminum tank? Removing the tank is not an option - teak & holly floor would have to be removed as well as sink cabinetry etc. Baffles in the tank make installation of a liner or bladder near impossible. I was told by someone with a knowledge of chemistry to use the product that is placed in a shower and sprays automatically to kill mold. He also said hot water was the best wash to use.


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## wenger230 (Dec 27, 2010)

Now, This is becoming very important to get installed a rain water tank in a house to save the water and making the country save and secure in future.

water tank


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## mitiempo (Sep 19, 2008)

Were you looking for a sailing forum?


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