I bought this... http://www.growell.co.uk/p/0123/Manual_pH_Testers.html

Ph means.... acid & alkaline... u need to neutral them out.

If it is too high OR too low u add... http://www.growell.co.uk/p/0128/pH_Up_and_Down.html

I dont use it though... I find if u boil it & leave the water overnight your PH will be perfect instead of messing around with these chemicals. PLUS ITS CHEAPER !!!
dude0 Reviewed by dude0 on . few questions i hate to ask a newbie question but i wanna know...how do you control the ph...how do you check it...when i did my first grow i had some nice females and they looked beautiful and everyone thought so...but i never bothered with the ph....what is it and how do u make sure you keep it at the level it should be...im not sure on how to adjust it is what i guess im trying to say....also i would like to know....i want to use compact floros till my plants get good enuff size to be under my 400w Rating: 5