Is there a pH controller?

Me neither I test two of them. I dont have them any more. They sell for 120 bucks and for the same price I can get a hanna 9044 which has a digital display, ph to the tenth, microsiemens, ppm, and temp. and is a constant monitor which plugs into the wall.

I have a Hanna grocheck (ph and EC) which is wall mounted like yoursand a cheap pH pen and bluelabtruncheon. All three are calibrated and I use them all to ensure my meters are accurate. Truncheon although does not have the two decimal places PRECISION, it still measures entirely accurately, I've tested it all through my grow with a range of concentrations and is as ACCURATE.

You had me doubting it again so I just tested. If you want I can show you a photo of before, adding nutes and the truncheon reading after to prove to you its not shit. but alas i cant be arsed and know my instruments are accurate

I'm not a big fan of hanna, all the ph checkers i got from then broke within 3 months of constant use..

Also where did you see them for $20? I'll have 10... sure you're not talking abuot the nutri-wand, the cheap imitation which costs about that?

I was pissed that it would not read epsom salt so I called the place in New Zealand to find out what was up. They told me they sell them as a promotion for there really accuarte testers for 19 bucks in bulk to the US. They are usually 120 in the stores. Some one is banking. I brought the ppm up to 1000 and then started dumping in epsom salt on both of them and the thing accually dropped one time. I like the way they light up when I stir the nutes and casting spells on the plants is cool but I just had a bad experience with them myself.

Get ready to see the auto ph doser setup. I'll be posting the tutorial in the next couple of days!

Cant wait. Any preposting info?

Well, everything together cost me just under $100 and is extremely simple to setup. Seriously, it's foolproof. You don't really need any construction skills for this one.

For how long is it automated to run for maintaince free?

Well, I'm just about to start writing up the tutorial, so just be patient ;-) But since you ask, it depends on how concentrated your acid reservoir is.