there are two things to worry about with hydro. one is the ph and the other is PPM. I have purchased test strips that only cost about $7 for a small tube of them but which normaly last through the complete grow. One thin I have found though is that I have always had to lower never had to raise the PH. with Hydro they call for it to be around 6 as this is what allows the roots to absorb the nutrients. The other thing is the PPM (parts per million) I have had to set up a reverse osmosis as my tap water had to high of a PPM(560)(very hard water). You can get away with bottle water. If you can not afford to by the meater for PPm then I would measure out the food in the amount if water in the res( as per instuctions). Mark it on the inside of the res the water line. Each day add just water to get to the same level. As the plants grow you will not belive the emount that will evaporate. That way the ppm will never go higher then target level but will decrease as plants use up the food. Now I completly empty the res once a week and run just water for 24 hrs then add food. This flushes the roots of any built up nutr. and prevents lockup. When you can afford it buy the equipment this gives you a better idea what the plant is doing. Have fun
Elfmannbca Reviewed by Elfmannbca on . growing hydro with no way of checking ph i know i should have waited to get the ph pen but i couldnt. i know that ph should be aroung 5.5 -6.0 in hydro. everything is looking good but im kinda nervous cuz i dont want to lose my babies.i heard that ro water is 6.0 then when you add the gh 3 part form.the ph will drop to around 5.8.is this true. Rating: 5