first EBB n FLOW setup questions

Looking good, g0, I think you got the nute thing dialed in. If you're at 950 with 120ppm water, that looks about right for this stage of growth.
Some general comments - back when you cut the nutes back to 750, and the pH kept rising, that's normally a sign that the plants need more nutes. But you timed it right, the weaker strength gave your roots time to establish & start using more of what you were giving them.
A caution on the "dark green" you said your leaves were beginning to show - if this is new top leaves, that might be a sign of a bit too much N. You don't want pale yellow-green leaves (too little N), but you don't want dark emerald green either. Monitor closely.
A vague and general rule of thumb - sativas need a weaker solution while indicas might eat you out of house & home. You're at 950 now, about 820 plus the water ppm. That's good for a sativa dominant strain, but a nute hungry indica strain might benefit from more as the veg continues. 1200-1300ppm is not out of reason for hungry strains. Just watch your ppm's & pH. If ppm goes down/ pH goes up, they can probably stand more nutes. Inverse for if the ppm goes up / pH goes down, it's getting too strong.
When you find the "sweet spot", note this for the bloom cycle. The high side of ppm's during veg is where you want to be once the plants bloom.
A word of caution, since you have hard water, evaporation can cause ppm's to artificially creep up crazy high between reservoir changes. These are minerals from the water, not nute strength causing the higher artificial readings. I've seen ppm's as high as 1600-1700 when using hard water, with no harm whatsoever to the plant (and you'll NEVER have a cal-mag deficiency which is about the only nice thing I can say about that). Observe the plant, watch pH even more closely, and act accordingly.
Light height - these plants are growing healthy, start lowering. I'd drop to 30-36" immediately, then continue lowering by 4-6" daily, down to about 18". As long as they keep showing healthy growth they will use the extra light to veg even faster.
Flood frequency - I'm not a fan of rockwool because it can hold extra water, which can deprive the roots of needed oxygen. But you have transplanted to grow rocks (are those silica?) which should help once all the roots have grown out of the rockwool into the rocks. I would increase frequency and monitor closely, while trying to get to 4 flood cycles per 12 hour light-on cycle. No need to flood when lights are off.
For future grows, I would strongly recommend changing over to hydroton. Go to 2X2" rockwool cubes for germinating seeds / rooting clones, or better still, rapid rooter plugs. With RR's and hydroton, it's next to impossible to over-water your plant containers. Think of DWC / bubble buckets where the roots sit in water 24X7. With a well draining medium in your containers, it's easy to get to a flood cycle every 1 & 1/2 hours. The real benefit to this using hydroton is that each time the container floods and drains, the drain cycle pulls fresh oxygen all the way through the root zone. This improves everything - plant health, vigor, yield, etc. Even helps keep down the possibility of root rot when you keep plenty of oxygen in the root zone.
But watch this carefully when using rock wool, it CAN over-saturate and cause root health problems.
Set up an oscillating table fan at one side of your flood table, with the ability to raise it so that it continually blows across the tops of your plants & under the light. This will help with trunk strength & helps keep leaf sweat / humidity issues under control among your plant tops.
Get those loose rocks out of the bottom of your flood table, they don't serve any purpose & can be a medium for bad things to grow in.

OK, my buzz is wearing off & I'm getting hungry. Welcome to GC, hope this helps, & bestaluck to ya.

 

5.9 it is!!! Actually, Hydro likes 5.8 to 6.0 as the sweet spot. You can drift as low as 5.5 or as high as 6.1 without problems, and some drift is actually healthy. But if you stabilize at 5.9 that's perfect, and it's telling you the ppm's are right where the plants want it. SWEET!!!
AZAMAX - good product. Four applications, four days apart (days 0,4,8, & 12), and you should be safe to discontinue after that. This time of year is usually pretty safe from outdoor influences, so the advance treatment would just be a preventative against an unknown clone source. If you keep animals out of your grow area, and never go in yourself after wandering around through the woods or natural outdoor areas, you should be able to keep a bug free area for some time.
The girls are looking good, keep up the good work. And thanks for the link on the grow stones. I stockpiled a couple of bags of hydroton when they quit manufacturing the real stuff and never got the courage to try the inferior hydrocorn or grow rocks. But I've heard good things about the silica grow stones, may need to give it a try when I get tired of cleaning all this hydroton

Be checking back, keep us posted on your progress.

 

Hey g0t, been a lazy assed grumpy pissed off frozen shut in the last week or so, sorry I haven't dropped in sooner. The girls are looking really good in these pics, keep it up.
Where you settled for ppm's sounds good; just watch the trend every couple of days. If it starts dropping before you top-off your reservoir, it's telling you they can use more nutes. One of your strains looks like an indica dominant strain, and those can usually tolerate more nutes & reward you for it. But the other... looks a little sativa-like which isn't as tolerant / doesn't need as much. You might have a mild dilemma & just have to go by the looks and experiment mildly.
Two gallons a week, heh heh heh.... wait awhile, they will gobble a couple of gallons a day .
If you're flooding for 15 minutes, you could easily go every 3 hours (I go 2 in bloom). Play with it.

Since they are exploding, time to think about the stretch when you flip to 12/12. I always count on a 3 X stretch when flipped, so I flip when they are no more than 16" tall. Gives me a 48" average plant height after stretch, which is about all I can tolerate without running out of ceiling room & getting into the light.

Humidity at 52-78% - see what you can do to bring that down. Good air exchange can help a lot, exhaust your grow room air & pull fresh air from another part of the house. Once you get into hotter more humid months, and you're in bloom, 78% is waaayyy too high & can encourage bud rot / mold. Experiment now while you have time & it won't hurt anything.

Check your later posts later, it's dinner time

 

Don't use molasses in hydro, it will clog up your pumps.

 

 
TOTALLY agree with dawill on this. I've never used Pure Blend nutes but I know they are an organic based plant food. Organics & pure hydro... never had the nerve to try it. My reasoning being that in order for most organic mixes to reach their full potential, they need a healthy population of beneficial micro-organisms which won't propagate very well in a pure hydro environment. It can be done, but dosages have to go way up & treated much more frequently. But... more & more nutrient vendors are coming out with supposedly hydro-compatible organic nutes, so we'll see. Me, I'm waiting for someone else to do the experimenting
Just watch for stinky smells coming from your reservoir, and/or slimy roots. Both signal trouble.
But molasses is definitely a no-no. You HAVE to have a dirt-like medium for this to benefit (works with hempy buckets / perlite, or coco coir, but not pure water.
Something like GH Flora Nectar seems safe - it's a sugar based additive but more refined and stabilized so as not to cause stink / rot problems in hydro.

Yield is going to be hard to predict. The "gold standard" is 1/2 gram per watt of light, per month of bloom time. That would be 2 pounds under ideal circumstances. But sooooo many variables with this - strain is foremost, along with grower experience, pot size, number of plants... yadda yadda yadda. First hydro grow, seven plants, 1000W light, if all goes well for ya, I'd expect a pound or better. Could be less, could be way more. I'm gonna predict 512.4 grams (but I'm full of shit & it's a wild assed guess )
Keep LST-ing the plants during the stretch to open them up, try to keep the top leaders pulled down even with your strongest secondary branches (even plant canopy), watch your nutes, pH and environmentals... room temp, reservoir temp (try to keep it in mid / upper 60's) all will help. As mentioned earlier, humidity can kill ya if it causes bud rot.

Mos'def' plan for more clones next time, you can never have too many (unless you get caught )

Plant height will not be restricted by the size of the pot... I've had 6" square container plants consistently hit my lights at max. height. But container VOLUME will help per-plant yield, perhaps better than anything else you can do.

Increase in ppm... a lot of that can be due to evaporation, flood tables are bad about that. And the high ppm water won't help. It will definitely make your ppm's go sky high during full bloom when the plants are drinking like crazy... I've seen 1800 ppm with hard water & without frequent reservoir changes. But this is different from NUTE STRENGTH that high, which can be deadly. Lay off the cal-mag supplements when using hard water, you definitely don't need that.
As long as your starting mixture doesn't go any higher in ppm's than you did during late veg, you should be OK. Artificially creeping high ppm's, as long as plant health shows no stress, can be managed. The wild card is that you never REALLY know if it's nute strength or hard water mineral build up causing the creep-up. When in doubt, or at first sign of nute burn / plant stress, flush and change the reservoir to new nutes.

OK, dinner time again, check back later. Hope this helps.

 

g0t, 3X is pretty typical, a lot depends on strain (sativas are worse - can go 5X), but over the years, I hope for 2.5 & pray it stops at 3X - a 16" plant becomes 48". If it goes worse, string / LST is your friend, kinda like a red solo cup
The burst of growth you're seeing since going to 12/12 is the "stretch" that gives you 3X; it usually lasts 2.5 - 3 weeks then stabilizes as the buds set & start to fatten.
LST looks good, no bugs --- f#$%ing GREAT. It always worries me to bring in clones as they are an easy way for mites to hitch a ride. Keep all animals out of your grow room (cats are really bad), don't even go in yourself without changing clothes if you've been strolling around in the yard or the woods. Chances are you can go for a long time with no bugs as long as you take precautions to keep them out.

Flushing, since you're trying the organic route you can get by with 3 days' flush. Just use pure water, don't have to pH balance (the right pH range is only needed for proper nutrient uptake; they will still drink water regardless of the pH).
Bloom stimulants - afraid you're on your own there as I haven't done organic since I grew outdoors. I use GH liquid KoolBloom with great results but it's mineral. I checked my catalog, GH BioBud is their organic equivalent.
Molasses alternatives - see my previous post. Or any of the "sweeteners" on the market should work. I do know of several hydro growers who have used FloraNectar with good results. Main ingredient is raw cane sugars & molasses (processed). The only thing not organic in this is "vitamins & essential minerals". Nothing that would violate your organic ways, IMHO, but that's up to you.

Later dude, gotta shop for seeds.