Anyone built the PH doser in the faqs? (other than Gen)

I'm seriously considering building the DIY PH doser in the FAQs.
http://boards.cannabis.com/showthread.php?t=58098
I was wondering if anyone else other than Gen has tried one, and if so, what do you think about it? Any thoughts, ideas or additional suggestions.

I want to be able to mix up my nutes in the sink but not worry about PH at that point, then dump them in the reseviour and let the doser take over. Of course I would turn off my pump until PH is stablized. Is this the general idea?

Right now I am adjusting my PH at the sink, and sometimes I have to go back and fourth serveral times with the PH up and down if I miss my mark. Sometimes I get it right on the first time and sometimes I don't, and when I don't it can be extremely frustrating (I know, I need to chill a little). I hardly ever check my PH after it is in the resevior, but when I have, I noticed that it has jumped up quite a bit in a short time. I've never done anything about it, but I've noticed small problems here and there that could be PH related. It would be nice to have it right all the time and not have to do much to make it happen.

I have to add PH down to my nutes, so I need to do it just like in the FAQs, correct? I mean I need the controller Mountain Man recommends; the one that is an acid injector, right? The lower the PH, the more acid content, correct?

I think I'm going to try this even if nobody else has. It would be nice to avail myself to the knowledge of the ones who have gone before me though, if any.

The problem is in the res. you need to keep that constant becouse as the water and nutriets get used the ph rises its prettly simple you can use this controler but i recommind a more percision dossing pump than that one you have to dilute or you could use to much to fast. If you have the cash use one of these and if you really do buy the all in one its as simple as plugging it in, and if you have know how build it super easy. This is just one good place to find these pumps and they make their own systems.
http://www.automatedaquariums.com/h_sys.htm

they also sell just the pump which can be used with the milwake for i think 75