the spud key will work, unless the fitting is seized. Something similar is often found in old radiator tails.
I don't like them, and would prefer to use a fitting that an ordinary spanner will fit. I suppose, on assembly, you could put PTFE tape on the threads, AFAIK it will prevent future seizing, as well as (where the thread is the seal) improving the water seal.
BTW your "softener" appears to bve a polyphosphate dosing device, you fill it will a chemical that slowly dissolves into the water and I believe makes soaps work bettter. Some washing powders contain (contained?) phosphates which can cause biological imbalance in waterways. The tech is well known and various devices are available, including a mesh bag you can hang in the cold-water tank, if you have one.
A proper ion-exchange water softener (regenerated using salt) does actually soften the water, and is much better.
I don't like them, and would prefer to use a fitting that an ordinary spanner will fit. I suppose, on assembly, you could put PTFE tape on the threads, AFAIK it will prevent future seizing, as well as (where the thread is the seal) improving the water seal.
BTW your "softener" appears to bve a polyphosphate dosing device, you fill it will a chemical that slowly dissolves into the water and I believe makes soaps work bettter. Some washing powders contain (contained?) phosphates which can cause biological imbalance in waterways. The tech is well known and various devices are available, including a mesh bag you can hang in the cold-water tank, if you have one.
A proper ion-exchange water softener (regenerated using salt) does actually soften the water, and is much better.