Yes, same house. The issue earlier in the year with the sick fish was ammonia, but I hadn't even considered Phosphate at that point. The manganese issue appears to have been resolved but flushing the mains several times, and keeping it up. It hasn't appeared for quite a while.
BBA has struck twice, all plants die, which leads me to believe I've always had this issue.
I add a little hot water to bring the temp up close to tank temp, then add to tank. Never been keen on adding straight cold water, especially with the heater off. I'll start boiling fresh cold water, then adding to the buckets. Have to be quick as repeatedly boiling water increases sodium levels.