I've recently been in touch with Truma about the inflexibility of the Ultraflow hose, (which is available in 800mm and 100mm lengths). Apparently they have had to start using a hose which is less flexible because of health concerns with the plasticisers which are used in food grade plastics. Truma's suggestion is to put the hose into warm water which will make it more malleable but, to my mind, this is not a very practical solution to the problem. I was using our caravan in the recent cold weather and the hose was near rigid and kinked very easily when putting it into the water barrel. These kinks must reduce the water flow rate. I'm sure Truma can come up with a better solution.
Connected with this is the Ultraflow Water Filter. It would appear that these are prone to leaking because of the plastic cracking. Thankfully, in my case at least, the leak was to the outside of the caravan and only occurred when the pump was running. The plastic splits when the filter is changed and the cap is screwed on too tightly. Tightening the cap even more in the hope of stopping the leak from under the cap only makes matters much worse and increases the length of the crack. I had to find a solution whilst I was away with the caravan and found that epoxy resin adhesive (Araldite or similar) pasted over the crack stopped the leak having dried the housing and then slightly roughened the plastic around the crack before applying it. (A manicure emery board worked well). I have also left the filter out on the basis that I won't need to take the cap off again to change the filter. If the water is not being drunk I can't see the need to filter it especially as the filter is recommended to be changed every 35 days. I'm surprised that Truma have continued to make a product which, it would seem, has a known fault.