I saw a thread before where some one made theyre own dosing system out of a couple Tom's Aqualifters and a gang valve. I was thinking about making one but I wanted to hear anyones experience on using them, if anyone has. Are they accurate, and more importantly does theyre accuracy last over time? It seems like a really good idea, but at the same time I could see the possibility of the pumps getting clogged or mineral build up in them.