Commissioning the fresh water system

My last UK boat had a UV filter, whether it did anything I don't know. The one I had on my fish tank didn't seem to do anything

The last place that I lived remotely had huge water tanks and huge UV filters - again I don't know if they did anything but I guess the company had covered it's legal obligations

W.
 
Have a look at swimming pool uv-c treatment.

you need something with a decent flow rate....ideally rated a number of times over your actual rates.

they will all be mains power so perhaps some kind of circulation system back to the tanks? It could clean you water whilst on shore power or generator perhaps.

I used to run commercial pools and one had a uv setup. We could run the chlorine level much lower but I cant imagine any uv system practicable for a boat will sterilise the water on one pass.

I’d still put something in the tanks though for growth on the insides/pipes etc....
 
That's my thoughts as well .... dosing tanks must be a more sure way ? I know when I do mine ... I mix the tabs into 5lt containers and then pour in via the filler pipe - making sure it gets splashed around the entry .. and all the pipe etc.
Then once a decent amount has had time to kill all in the tank as well as fumigate ............ I then pump whole lot through on-board systems to get them really sorted.

I used to use standard Chlorox ... but when I bought the estate out here and saw I had two wells ... one active for the house - I changed to the tablets. (We have town water now .. well is not used anymore).
 
Tank is 70ltr .... system is about 2ltrs .... 1 tablets added to each 5ltr container (each tablet is good for 20ltrs) ...

Once filled OK ... that's tank overflowed and then excess pumped through to basin and overboard. A free space for 'fumes' of about 10 ltrs made by the pumping through.

She can stand for a few days and then pumped out.

If that doesn't kill the 'beasties' then what would ???
 
Forgot to add :

I used to caravan as well as Boat in the UK and I was very friendly with caravan dealers and service guys. One of the topics was FW systems of vans and boats .....

They maintained that the biggest problems were not the tank - but the piping for bacteria and 'unhealthy' beasties. That most people thought about dosing tanks for winter storage / re-commissioning in spring etc. but ignored the piping and valves etc.
The second item of course is the use of non-food grade pipes ... by many thinking that its only a plastic pipe.
 
There’s something in the local chandlers ( CdA ) in tablet form , looks like vitamin tabs .A small tub the size of salt pot is approx €25-30 So initially feels pricy when you pick it up .......but treats 10,000 L .One tab per 100 L or something so once on that you just drop as appropriate the correct the number in.
We have a 500 L tank so a tub basically lasts most of the season @ 20 fill ups .
Sorry I can,t recall the name of the stuff .
Italian version is power and comes with a little scoop to dose .....works out the same value .
 
Chris H said:
Fernox are specialists in water treatment, I’ve got a 600 litre tank to clean.......how many tablets do you suggest.
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Fernox I know from adding to Central Heating system and cleaning out outboard water channels .... of course they offer different products under the Fernox banner.

Tablets ? if you are asking me about Oasis as I use ... already answered ..........
 
Doing some sums, a typical galley pump delivering 3 gallons per minute via a half inch bore hose moves the water at six feet per second through the hose. A 12" UV lamp would treat each bug to a burst of UV for just one sixth of a second.

Gamma rays might work in that time but not UV, but having a lump of uranium 235 kicking around in the bilge might call for some PPE.
 
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Refueler said:
Forgot to add :

I used to caravan as well as Boat in the UK and I was very friendly with caravan dealers and service guys. One of the topics was FW systems of vans and boats .....

They maintained that the biggest problems were not the tank - but the piping for bacteria and 'unhealthy' beasties. That most people thought about dosing tanks for winter storage / re-commissioning in spring etc. but ignored the piping and valves etc.
The second item of course is the use of non-food grade pipes ... by many thinking that its only a plastic pipe.
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Indeed so, which is precisely why we never drink the stuff. It's potentially contaminated right up to the tap.
 
Some good suggestions and advice above, some not so useful. After dirty tanks and poor supplies, absolutely the greatest risk to on board water hygiene is the internal surfaces of the tanks, pipework and fittings. A slime or biofilm will form over time created by small amounts of bacteria, especially in stagnant water left at ambient temperatures. The biofilm will then release bacteria back into the water. UV in this circumstance does not help greatly and by far the best cure is a chemical additive. Chlorine based treatments such as Milton or Hypochlorite will kill bacteria but will not remove the nutrients or biofilming. For this you need a product more dedicated to biofilm removal. Most water treatment companies will be able to supply and you will only need a small amount to treat long term. It almost goes without saying that in order to ensure no organic materials find their way into the piped system, the tanks need to be spotlessly clean! You also need a good quality water supply (I have seen some really horrific "potable" water loaded in Indian and African states). Of course, there are other options for more specific problems or circumstances and this is just very general comment. If you want any specific help with particular worries feel free to pm me any time. I've had over 25yrs working with MCA, Port Authorities & commercial shipping lines taking care of their on-board water quality.
 
Catalina36 said:
Doing some sums, a typical galley pump delivering 3 gallons per minute via a half inch bore hose moves the water at six feet per second through the hose. A 12" UV lamp would treat each bug to a burst of UV for just one sixth of a second.

Gamma rays might work in that time but not UV, but having a lump of uranium 235 kicking around in the bilge might call for some PPE.
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I know UV does work in proper circumstances - but in this case is it similar to the claims of Magnetic Systems that allegedly kill bugs in diesel ?
 
Refueler said:
I carry store bought water to supplement the Beer / Wine inventory for drinking .....
All FW from the tank is for cooking / tea / coffee use.
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Same here. Actually, SWMBO prefers bottled water also for tea and coffee, and she uses the tank water only for cooking, wherever it's boiled, as for pasta, boiled vegetables, etc.
 
All our drinking water (including the dogs) is bottled. During the peak summer, bottled water can be in short supply and the supermarkets rammed with tourists, we then refill the water bottles from home. We use the plastic bottles only a few times because of the harmful plastics but we usually have a huge amount of empty bottles by then. We also have a large collection of proper BPA-free hiking bottles that we use (also handy for our long dog walks).
I know that this sounds anti environmental but we recycle and it saves having to repeatedly rinse out the fresh water tank. The non premium supermarket non branded bottled water is surprisingly cheap
 
Bouba said:
All our drinking water (including the dogs) is bottled. During the peak summer, bottled water can be in short supply and the supermarkets rammed with tourists, we then refill the water bottles from home. We use the plastic bottles only a few times because of the harmful plastics but we usually have a huge amount of empty bottles by then. We also have a large collection of proper BPA-free hiking bottles that we use (also handy for our long dog walks).
I know that this sounds anti environmental but we recycle and it saves having to repeatedly rinse out the fresh water tank. The non premium supermarket non branded bottled water is surprisingly cheap
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Regarding bottled water ... its interesting that a number of well known brands are actually NOT natural spring waters ... but factory produced.
In our local Supermarket ... the 60 cent 5ltr is natural ... but the next shelf has a well known brand 1.5ltr bottle at 2x the price .... its not natural water but gassed in a factory.
 
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