Yellow Spots!

That's the only one. I've grown legitimate vegetables hydroponically when I was student so I know the basics, but that was in a professional lab with all the best equipment.

whats the temp and humidity?
and night and day?

The plant responded to the corrected pH, when I tested again the next day, whatever the plant was doing, the pH was raised up a few points, so I lowered it again.

Temp is 75-78 F, I don't have a measure on the humidity, I feels humid to me, maybe 70%, but I do keep a fan on it at all times.

I've got it on 20hrs/ 4hrs. It's still producing new growth and the new growth isn't curling up like a taco, but the tips are starting to yellow.

Recovering slowly I guess, still growing.

wowo glad the little girl is still kicking it. it could be Mg def. but i think its to late for that. so waht are you feeding here and how often?

Well, I bought a digital pH tester on ebay, I'm waiting for it to come in the mail before I change the solution.

huh well let me know once you get the Ph tester

A lot of the advice you have been given has been for soil. For hydro PH 5.6-5.8. You absolutely need fertilizer, the plants won't grow with just perlite and plain water, they must have food, start at 300 PPM and go up 200 each week until you get the kind of growth you want without damage. Change reservoir of water every week. Keep airstone in reservoir to pump up oxygen levels. Make sure the fertilizer is a good N-P-K balance and has micronutrients also.

your having the same problems as me.. my plants are still growing and a little less yellowing/rusting but i still cant figure out whats wrong with mine.. my temps are a little high and my humidity is really low in my furnace room. one of my plants was nearly all yellow and somehow just stopepd turning yellow and grew green from there up.. so its back to growing again but took like a 2 week worth of growing hit.

let me know if you figure out what was wrong ive flushed mine and added no nutes and still didnt help. i got 10 growing and like 7/10 are yellowing/curling leafs upwards

Here's the next three day's pics. It seems to be back on track. She's growing little branches off of the dead leaves at the bottom, and the young leaves that were starting to yellow have greened back up.

I have the pH kit where you match the colours. It's just not that specific. Whatever it's at right now, it seems to really like, so I want to recreate the conditions exactly when I change the solution, so I'm continuing to wait for my package in the mail. There's still nutes in at about 1/8th the recommended strength and I'm spraying her with a epsom salt solution that's 1/2 tsp/litre, and there's a good air supply underneath. I have a bubbler on 24/7. I'll definitely up the nutes when I change the solution. I think she can handle a little more now.

I'm also planning to snip the top and encourage more branching. This variety is called Brain Candy, it's a Burmese x NYC Diesel and Cotton Candy which I bought because it's described as short veg. recommended for indoors. So far it does seem to grow fairly compactly. I'm assuming I'll get more yield of the sweet stuff if there are more branches. Can anyone confirm or deny that thought? I plan to keep it in veg for 2 or 3 more weeks then put it in bloom (6-7 weeks total since germination), however, I would definitely keep it in veg for longer if the additional branching is really helpful. Any thoughts?

looks like its gonig to make it !!