What to clean/treat polyurethane flexible tanks with?

[maej]

I have a Duratank flexible tank which is apparently made of polyurethane. When I bought the tank from Hovercraft Consultants they warned me not to use chlorine treatments to clean the tank, I have since found out it is because chlorine degrades the polyurethane the tank is made from.

Since I can't use any of the typical tank treatments because of the chlorine, what options are there for cleaning / treating the tank?

I'm not too bothered about the taste as long as it is safe. At the moment I only use it for washing up, I always bring bottled water to drink, and in the long term I'll get a good filter, but I still need the tank to be safe.

 

[vyv_cox]

At least one of the yacht freshwater purification products is based on silver. We have a bottle aboard but I don't remember the supplier. Jabsco do a silver impregnated charcoal filter for less than £40.

 

[macd]

At least one of the yacht freshwater purification products is based on silver. We have a bottle aboard but I don't remember the supplier. Jabsco do a silver impregnated charcoal filter for less than £40.

I'm pretty sure Hovercraft Consultants offer their own purification cartridge, which is inserted on a tether into the tank.

 

[Momac]

I dont drink water from the boat tank and dont use boat tank water for cooking. I bring a 5 litre water bottle to the boat which I buy from the supermaket and re-fill from the mains. One of these bottles survives a season than gets binned.
I do use the tank water for washing up and washing myself including brushing teeth, as does my wife.
The tank on the boat is pumped out and left empty over the winter . It gets a full tank fill and is fully pumped out then refilled again with mains water in the early spring.
No chemicals added.
The wife and I are still alive after six years of this .

.