i use the cheap test, where u fill the bottle with water from the res and add drops to see the color. after adding the pH down it has gone down to 7 but always goes back up to 8 the next day. im gonna flush the reservoir soon and add more pH down this time n see what happens.
one more question, should i pH the reservoir first or add nutes first? thx in advance
OK. You must remember that I am on my first grow, and there are plenty of guys out there with more knowledge and experience than me.....
That being said, I would HIGHLY recommend getting a good pH and EC meter if you plan on going the hydro route. I paid less than $200.00 for both of mine. I understand you may be on a budget, but you really need to know these parameters to maximize your grow.
Anyways, working with what you have, I always mix my nutes in a separate container prior to putting them in the res. It's my Saturday morning thing.....cup of coffee and a smoke and I'm ready to go. I fill the water the night before and let it sit. First thing Saturday morning I add nutes according to the GH Nutrient calculator, mix them up and let them sit a couple of hours. I come back and check pH and EC. EC should be very close to plan if you measure your nutes carefully. After checking the pH I add the required amount of pH down, mix and let it sit for a couple of hours. I come back to re-check and add additional pH down if needed. I take copious notes on every batch I mix, and that allows me to know pretty accuately how much pH down I'll need to drop the pH in a 10 gallon res.
I let the batch sit overnight and check first thing Sunday morning and adjust as needed. (Rarely needed) After dumping the existing res, I give the container and the pumps a good scrubdown. I then refill and flood to make sure all the connections are tight.
When I was having problems with my pH rising, I would add 20 ml of H2O2 (35%) to the res every other day, and that fixed it. I wasn't very aggressive, as I believe you can mix the 35% at 1.7ml per liter while using non-organic nutes.
To wrap this babble-a-thon up, get the good analyzers if possible, add pH down after you've introduced your nutes, and add H2O2 if you think you may have some critter issues in the roots.
Good luck with your grow!