Fresh water tank gunk

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35mm

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The boat I got a few months ago has orange coloured gunk in the bottom of it. Probably fungus but not too sure. Was happily using the water with a bit of treatment for some time before we noticed the orange coming through. No ill effects.

I put a cup full of bleach in, added water and left it 24hrs. Pumped out and flushed through several time. That seemed to do the trick until we took the boat out in a lumpy sea which must have stirred it up again.

The water tank is under the cabin soul. I don't want to cut a hole in it and fit an inspection hatch as that would cause a bump in the floor.

Any ideas how to get rid of this stuff?
 
its quite possible to use a steriliser and water tank treatment to make sure nothing stays alive down there. however, getting rid of the bits might be difficult. all i can suggest is you treat the tank and then flush it lots of times with fresh water.
 
35mm said:
The water tank is under the cabin soul.
Click to expand...

Er, prey(sic) for cleanliness?



But seriously...sounds just like I had in equally inaccessible tank. I did the same, bleach and lots of flushing, and as soon as the weather kicked up a bit - soup! It was a lesson how much gunk the bleach cleared out of the pipes between tank and taps though.
Can you open unions close enough to get a Pela pump tube inside and try to suck those last bits out?
Or, as I did, just fit a filter and not worry as it was dead. It never did any harm when it was live anyway - just looked unpleasant. Any tank (water or fuel) I ever fit again will have an accessible sump drain and pickup above the bottom.
 
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Treatment with a chlorine bleach ( use a thin one rather than a thickened one) should kill anything there is to kill.

A suitable dose rate would be about 30cm³ per 10 litres of water


If the tank is not accessible thorough flushing and lumpy sails is probably your best bet at clearing any residue.

Routinely dose water going into the tank with Milton solution at the rate of 5cm³ per 10 litres if you have any doubts. Dont over do it . Chlorine flavoured tea is awful!
 
Any ideas how to get rid of this stuff?

It sounds pretty bad in that tank. This is beyond chlorination or super chlorination.

Cut a hole in the top or side and carry out a thorough scrubbing out of this growth and all slime on the surfaces. (slime protects some bugs from sterilizers) No harm in using bottle brushes in the pipework as best you can.

Once clean seal it up, super-chlorinate. Dump that. Flush. Fill with dosed fresh to achieve 0.2ppm free chlorine (same as tap water)

Now, the organoleptic bit. Pour water into a clean glass, hold it up to daylight. Q. should be crystal clear. is it cloudy? is there matter in suspension? is there sediment? smell? sip taste?

If it passes organoleptic test have a sample taken for lab analysis. Your port health authority or environmental health dept will help you.
 
35mm said:
The boat I got a few months ago has orange coloured gunk in the bottom of it. Probably fungus but not too sure. Was happily using the water with a bit of treatment for some time before we noticed the orange coming through. No ill effects.

I put a cup full of bleach in, added water and left it 24hrs. Pumped out and flushed through several time. That seemed to do the trick until we took the boat out in a lumpy sea which must have stirred it up again.

The water tank is under the cabin soul. I don't want to cut a hole in it and fit an inspection hatch as that would cause a bump in the floor.

Any ideas how to get rid of this stuff?
Click to expand...

Bleach/Milton will kill bacteria but not get rid of the residue. However, the residue will gradually rot away and bit by bit (literally) be flushed through the system.

My recommendation would be one of both of the following,

1) Fit a fine filter in the line to trap all residue so you/your crew don't drink or eat it
2) Cut the dreaded hole and clean the tank properly

Piers
 
This may be of use http://www.ybw.com/forums/showthread.php?t=219815 If you have alongside power, you might try getting a pipe into your tank via the filler hole, removing, existing hose perhaps and attaching to a wet vacuum cleaner (VAX?); even possible to attach a garden hose on end by bodging a suitable adaptor. Then try sucking out the scum in your tank. Finish off by fitting a good quality filter between fresh supply and tap so that the water you draw is clear. Worked for me.
 
Timely thread, I pumped out my flexible 100 litre Nautica tank out. The water was fine but for the very last bit, about 5 litres of frothy brown stuff came out :eek:

I took it out last weekend and will treat as suggested, maybe with Miltons as it is plastic. It's in the bath waiting for an external scrub as well!

NOTE; Always drain ALL the water out and check/treat each year!
 
All the above suggestions may work for you - you're in for a long slog to get it thoroughly flushed out. When I do my tank, I disconnect the outlet pipe and flush directly into the bilges so they get a wash and it's easier to pump out with the bilge pump, anyway.

Having got into this state, the chances are that the hoses are in quite a state, too, and it is nearly impossible to clean them. Once you've got the tank clean, change the hoses for new ones!

Rob.
 
Thanks for your replies. I can't cut a hole in it to scrub it out, because that would leave a lump under the carpet. The pipe work is clean. I have an inline filter, but the orange discolouration still gets through when the tank gets shaken up. I guess I'll have to just keep flushing and shaking!
 
35mm said:
Thanks for your replies. I can't cut a hole in it to scrub it out, because that would leave a lump under the carpet. The pipe work is clean. I have an inline filter, but the orange discolouration still gets through when the tank gets shaken up. I guess I'll have to just keep flushing and shaking!
Click to expand...

Getting the marina's hose (or the the end of a pressure washer hose) and stuffing it into the tank and moving it around may help get the orange growth loose.

Piers
 
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