Quote Originally Posted by reefbeaver
thanks man...you really know your shit....one more quickie....do I need to do a complete water change or can I do like a 20-50%...am I just looking to lower the pH due to all the nutrients in the water....on a tangent here but in the aquarium business I can buy a monitor system, you can hook up a pH probe to it and a controler on a CO2 system if the pH jumps to high you could dose CO2 through a reactor to lower pH automatically...This method is not for me way to much $$$ but if you have the means it would be sweet.
No you do a full water change every time. The plants will change the Ph of the water them self's so you will need to check it twice a day and keep it balanced.

We use CO² to enhance the grow by filling the room with CO² at high levels and keeping it there for hours at a time. Those controllers are around and are not very expensive but you would need to build a relay and a drip system the relay turns on and off. We use acid to bring the Ph down and you only use a few drops at a time the check it again then add a few more drops then check it again. Until you get it right you don't want to plant the Ph up / down game it a loosing game to play.

Raising fish and keeping fish is not even close to growing plants in hydro. In hydro the water is only a part of everything you need to know about growing quality in hydroponics.