Following some pipework changes and draining and refilling of the cold water tank we have fairly clear but yellow water coming from the cold water tank in the loft. A torch will penetrate the murky tank which is not pretty inside but is clear of dead animals, birds etc.
What had for a couple of years been a redundant run of pipework is now used for the water run from soon after the water softener to the loft tank. Water from the softener direct to another tap is crystal clear.
The changes were over 2 weeks ago and the water appears not to be getting any clearer.
The central heating header tank is about a meter below the level of the cold water tank and the level is not rising so I doubt whether the coil in the hot water cylinder is leaking.
The galvanised cold water tank is probably 45 years old and in need of replacement which will be organised soon.
Any ideas what could be causing the yellow water? (References to bodily fluids are not required!)