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S&S Swan Maintenance - Water tank cleaning
19 August 2020 - 20:57
Join Date: 24 April 2020
Posts: 18

Water tank cleaning

So I am getting into the weeds with the 47.

Seems the water tanks have not been used for years as there is what looks like pond scum in them and the water is the color of pond water!

SO _ I have emptied and flushed them multiple times with fresh water and bleach and fresh water and tank cleaner but on opening the access hole - where the suction unit is - the walls of the tank that I can get to still have a film on them. Easy enough to clean that part of the tank adjacent to the access hole but there are two baffles which effectively split the tank in thirds and make it impossible to direct a jet of water to the the other end of the tank!

Any suggestions at all as to how I get the rest clean, short of cutting access holes in the top to get to the other 2 baffled compartments? If I take the tanks out and steam clean them the problem of getting past the baffles remains.

Any chemicals/ other tank cleaning products that will attack the scum in those parts of the tank I can't get to..??

All and any help appreicated - am sure this problem has been solved before!


Best/ Adrian Little

Cygnus 47/048

21 August 2020 - 16:20
Join Date: 02 January 2008
Posts: 1547

Dear Adrian

As the tanks are made of stainless AISI 316 you could use quite strong chemicals for dissolving the remaining film. Usually chlorine is recommended for tanks, but it's main purpose is to kill bacteria, and it is not a cleaner, and in stronger concentrations actually will damage the steel surface.  
Try a liberal amount of dish washing liquid and warm water, and let it work for a while, the colour should disclose if the film dissolves.
It appears swimming pool manufacturers are aware of the algae problem, and sell cleaners called algaecides.
If you want to try stronger chemicals, there are charts with chemical compatibility on the internet.
Very important is to flush out all chemicals before using the tanks.
Kind regards

28 August 2020 - 22:37
Join Date: 07 October 2014
Posts: 74

hello adrian, i would do it int the way of filling some sand in.

but you need to move (sailing in good waves) or moving the tanks quiet a lot. best may if they are out of the boat.

than it is more easy to reach every surface.

check different corse.

on the end you can get the sand out.

i had plenty of the fine sand / dust in my tanks. accumulated from the dirt in the rain water and from the marina.

after a good sail, all was mixed up and i could get it out.

the sand method i did on my jerry cans. they came like brand new.


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