Dimtec,
You’re right, I wanted to say 4". Because I thought after the first feeding point Q will be reduced and you don't have 60 m³/h any more. That is getting worse close to the last feeding point.
option one- as I mentioned the problem is in the suction line ( more possible). By having...
by replacing 4" Flexible Hose with the existing suction line the problem should be solved. If you have 40m³/h lime slurry ( 4~12%) in a 3" line velocity would be around 4ft/sec that is low. recommended velocity for lime slurry flow is close to 4 to 7ft/sec( close to 7).
Thus I would say check...