I found out the hard way that the acid in vinegar doesn't do any good if you've got the wrong kind of media in the growbed - it just lasted for a few hours and then went right back up where it started .... you have to use a good acid, as badflash told me ..... it was muriatic ..... be right back .... I'll get a link to the thread ...... here it is:Clik
it's on page 11 of wolfracer's system build, and badflash says:
You can condition your make-up water with a little Muratic Acid. You can get it by the gallon at home depot. It doesn't take very much, so be careful if you use it.
and
You could calculate it, but depending on the species of what is buffering the water, you need different amounts. I put in an eye dropper full (5ml) per 100 gallons, wait an hour and test. Repeat until the pH is where you want it. Be sure to have lots of flow to be sure it is all mixed. As the pH drops, more limestone may go into solution, so it can take some time to get it where you want it.

Remember that pH is a log scale, so as you go from 9 to 8 it takes 10 times as much acid as it takes to go from 8 to 7. Go cautiously. Use rubber gloves and a face shield. You can't replace your eyes.
Perhaps someday he'll enlighten us about how to calculate it, but the way he shows is good enuff for me His idea of getting rid of the rocks was a good suggestion .... when I took out all the "lava rock" which I found out was some sort of fake product made of clay (and probably cement and lime), my tomatoes started to fruit, and my Guppies are being fruitful and multiplying .