i thought it was ph...

i'm about 2 1/2 weeks into my first grow right now. and as most newbs do, i started out overwatering my plant like crazy, then backed off after they started drooping and curling. now i water about every 3 days. at the beginning of the week i started to notice that some of the leaves were starting to turn brown and i thought it was from lack of oxygen in the roots so i added a bit of h2o2 to my water. then they started to develop spots and look really unhealthy, i figured that was from not testing the ph of the water. so today i bought a water ph tester ( i can't afford a soil tester at the moment.) its at 6.4 so i dont know that if its nute lockout or what. the temps stay between 75 and 80, i added 1/4 strength of all purpose MG to the water after i noticed the spots, they're under cfls. about 1/3 to 1/2 of them are afflicted and this is the pic of the worst plant (it was the healthiest until this started). it looks like all of the plants haven't grown in the past few days. aaaannnndddd thats all i can think to add right now. any suggestions??

flush (with PH'd water) & test the runoff water PH.
don't give nutes yet.

Goodness! Looks like the plague.

I would purchase some sterile perlite and mix it 50/50 with your soil and transplant that youngen into a bigger pot. You'll never over-water with a generous portion of perlite nor will you need peroxide.

After you get it transplanted, whack those dead leaves off.

Be easy with the MG nutes. At that stage, maybe a 1/16 - 1/8 tsp per gallon every other watering should suffice (if your using nutrientless soil).

good call on that testing the runoff water, i didn't even think of that. it was at about 7.2-7.4. so it's ok to flush them even though the soil is still a bit wetter than i would usually water them at? or would that just make the over watering problem worse? also vinegar lowers the ph and baking soda raises it right? i hope they dont die

What soil is you using?

clip the dead leaves off cus it can cause the plant to keep trying to keep those leaves alive even tho theyre not producing energy.it will dwindle the plant and cause the fresh healthy growth to start dying,read up on pruning.the dead growth is inhibiting new growth.the new growth looks perfectly fine on your plant even though ur plant is majorly streched out.

just regular run of the mill as cheap as i could find potting soil... i know.. i know... but i'm really really broke and this is more of an experiment...when i upgrade pots (probably about a week after they start growing again) i'll use the perlite and soil mix. yeah i noticed they were stretching so i doubled my cfls and the new growth since i installed them seemed to not do it anymore. thanks guys.

cheap potting soil is fine, assuming it's not pre-nuted. your runoff ph is a little high - you can add a little bit of vinegar to your water to lower it. 6.3-6.8 is the ideal range