Calcium Build-Up in Sanitation Hose

[SAMPATICO]

Can someone please explain the chemistry of the source of calcium crystallization in toilet sanitation hoses from sea water flushing? Calcium in sea water is less than 400ppm.

[zeehag]

you forget the salt of sea-- sea is briney and has a lot of different minerals. your build up may just be sea salt with these minerals in... try vinegar. it works.

[GordMay]

See ➥ Fouling - Wikipedia, the free encyclopedia

FWIW (not much, IMHO):

Elementary calcium reacts with water at room temperature, according to the following reaction mechanism:

Ca (s) + 2H2O (g) -> Ca(OH)2 (aq) + H2 (g)

This reaction forms calcium hydroxide that dissolves in water as a soda, and hydrogen gas.

Other important calcium reaction mechanisms are erosion reactions. These usually occur when carbon dioxide is present. Under normal conditions calcium carbonate is water insoluble. When carbon dioxide is present carbonic acid is formed, affecting calcium compounds.

The reaction mechanism for carbon weathering is:

H2O + CO2 -> H2CO3 and CaCO3 + H2CO3 -> Ca(HCO3)2

And the total reaction mechanism:

CaCO3 (s) + CO2 (g) + 2H2O (l) -> Ca2+ (aq) + 2 HCO3- (aq)

The product is calcium hydrogen carbonate.

[David M]

Bivalves get their calcium carbonate (shell material) from the water they are in. There are also salts other than sodium chloride that can accumulate when seawater reacts with urea. One reason to flush your head more than "just until it disappears".

Try lowering the pH of the water in the heads plumbing periodically with a mild acid like vinegar, let it soak in there, as zeehag suggests.

Hoses can also be removed and beaten to remove the scale. If you have to go through the hassle of removing head hoses then it might make more sense to replace them while you are at it.

[John A]

It's caused by urine interacting with salt water (sea water). Depending on useage, flush with only white dentured vinger. Liveaboards should do this once a week, followed by a tablespoon of vegetable oil.

[svHyLyte]

We have been using a product known as Salt-Away to help keep the hoses to our heads free of obstruction for 7 years to good effect. If you do have scale build-up however, Barnacle Buster is a very effective de-scaling agent available as a concentrate. Another product, RydLyme is similar and also quite effective but is reportedly somewhat less economical. Never-the-less, we have used RydLyme to good effect on our A/C system.

FWIW...

[Rakuflames]

Originally Posted by zeehag

you forget the salt of sea-- sea is briney and has a lot of different minerals. your build up may just be sea salt with these minerals in... try vinegar. it works.

That's right. That's why the stuff labeled "sea salt" has more taste than the older style table salt, which has those other minerals refined out of it.

[mikefp60]

Once a month I flush the heads with fresh water, empty the bowl then run a gallon of the cheapest vinegar I can find into it. Then let it sit for as long as I can stand it. Keeps the lines pretty clear and the backflow valve sealing off properly.

[minaret]

Any body else here use No-flex Digestor?

Jetvac Inc.

It's pretty impressive. The guys at Marine Sanitation showed me some examples before I started using it, for instance when they rebuild old heads and pumps they often come in in a garbage bag with the innards all fouled up. They just put them in a large container of water and pour in some no flex. It eats all the mineral deposits and gross buildup right off until the water is clear and there's almost no smell. It's amazing stuff. Will keep mineral buildup out of your hoses.