can I use lava rocks?
 

Hi,
I wrote to you about two months ago and ask about the 4" pvc pipes, Well I did it! I am using clorox bottles and I have two questions 1: can I use lava rocks? will it screw up the ph? 2: I have tomatoes and peppers, hot and bell, how often and for how long should I set the timer to water using the drip system?
I have my tank below ground level to keep the temp. down as it gets quite hot during the day here in Fort Lauderdale Fl. I am using General Hydroponics FloraMicr and FlorGro. Thanks for your help and web page!
Greg B.

Hi Greg You have to make sure the lava rocks have been sterilized because of the toxins that pure lava rock has. I would water every 20 minutes or so for 5 minutes and maybe more often as the plants get bigger or it gets hotter.
Ron