Same, i make up fresh batches every month. I found the dosing pumps to be a cheaper option for me.
I have always had problems with reactors, i could never get them set quite right so i went to the dosing pumps.
As a side note i am adding 250g (KH and CA) to 4ltr of water. Is there any reason why i can't add say 500g or 750g or 1000g to the 4ltr of water. It would then last longer which would be good.
At what point would i get a saturated solution.