in the milk line, 12 units/side, the surge was not quite touching the top of the pipe, in one place, in the middle, about 6ins. That line had been swapped rewashed time and time again, and the experts kept saying, no problem there, it was the tank, the water, the cows and every other thing, but not the milk line. We only found it, because we started stripping the whole parlour out, and lucky to spot it then, taking the pipes outside, just saw a thin film, in the sunlight, impossible to see without sun, or torch, sorted, bacto straight back down. As 24/24, we now have a surge on both sides ! After paying 2.5 thousand, to one '''expert''' firm, the best we got was, 'mmmm intriguing', and they never rung back, to see if problem had been sorted, we simply stopped using them. A very costly experience, under wyke, we wouldn't have been penalised.Do you mind me asking where the bacto problem was? I’ve got a niggly issue, I cannot get it below 40 and everything has been cleaned inspected, tried different tanks etc. Had milk tested which pointed to tank, scrubbed both tanks etc to no avail.