DWC Droopy leaves

[Agentbuckwold3]

Hey everyone,
So I made a post in the general section of the forum by mistake and got some good feedback but I figured I would post this where it belongs and see what happens. I started a very small DWC grow on July 1st. It's in a 18wx13dx48h grow box, in a 6quart reservoir with a 5-15gal air pump, under a 300watt LED, and I'm using the GH trio with claimagic at 1/4 strength and hydroguard. After a lot of trial and error I think I've narrowed the problem down to the reservoir temp being too high. The temp in the grow box has gotten as high as 90F and I've measured the res temp at 77F. The intake and exhaust fans just don't move the air enough. I've had very great growth and after some nute burn in the early stages I've gotten my ppm under control around 330 and PH has stayed between 5.8-6.0 so all new growth is nice and green, but starts to droop as the temp in the box rises when the lights kick on. The pics are from yesterday morning, yesterday afternoon(when they started dropping), to this morning after peeking up a little. After seeing that my leaves perked up while the lights were off I'm sure the res temp is too high so as a temporary measure I took my humidity dome (which I was already using with a towel to keep the humidity at a decent level) and filled it about a quarter of the way with water, and dropped the reservoir in it with 2 ice packs. If I go home and the leaves are perky I may order a larger container with a lid that I can cut a hole to the size of the top of the reservoir so it sits nice and snug, fill it with water and a much larger ice pack, black it out, and I think that will solve my problem. What do you guys think? With such a small system I don't see the point in investing in a chiller. Sorry for the long post.

[DW2]

Howdy Agentbuckworld3, The reservoir temperature is too high. I keep my reservoirs between 64° and 70° F (using ice bottles). The photo of the root looks good and clean (does not look like any algae is rowing). How often do You drain and change out the nutrients? GH recommends draining every 7 to 10 days and to use only pH'ed water to top off in between feedings. I normally get a 'droopy' effect when either, the water level gets too low between changes, or when the reservoir is drained. The plants recover within an hour or so after filling or topping off. Also, have You checked the recommended distance (from the plant) that is specified for the LED that You are using? If the droopy leaves appear only after the light comes on, then it could be heat stress, but I'm speculating because I use CFLs. I would recommend covering any unused net pot (even if it has clay pebbles in it) with aluminum foil to block out any light from reaching the reservoir to prevent the brown algae (root rot) from starting up. An other thing, I use the GH Maxi series of grow and bloom, and I use them at full recommended strength (as per GH's feed chart), and at 1/4 the strength, could You be underfeeding the plants? Just a thought.
Good luck with Your grow.

[Agentbuckwold3]

Thanks for the info DW2, I changed the res water last night which was a week since I first put the seedling in the reservoir. The light recommends 18" from a seedling/early veg and I've got it at 20" with no signs of stretching so I think I'm good there. My res lid is blacked out with reflective tape with an extra opening that stays covered for checking ph, ppm, and topping off. I used 1/4 on my first feeding a week ago and got some nute burn. My PPM was at like 480 so I did 1/4 strength again this feeding and dropped the PPM down to 330 and my new growth is looking much healthier. The other idea I had, while I'm at work and away from the grow of course, was to raise the light all the way to the top of the box where it will be right in front of the exhaust fans and elevate my reservoir to get to the recommended distance from the light. The light hangs in the middle of the box right above the intake fan (which was a weird place to put the intake IMO) so I feel like that hot air lingers for too long before it hits the exhaust and that's why the box is so damn hot.

[DW2]

I'm not sure that I completely understand the set up that You have, but the fresh cool air intake should be at the bottom of the enclosure and the exhaust fan at the top to pull out the hot air. One could also 'push' the air into the box at the bottom, but as hot air rises, the exhaust needs to be at the top. You also mentioned the PPM of the water, what has the pH been? I may be wrong, but I do not pay attention to the PPM. My local water supply runs around 869 PPM (per the annual water report) and the pH level is more important for the proper uptake of the nutrients. The range should be from 5.5 to 6.5 pH, and allowed to vary within that range as different nutrients are better absorbed at different pH levels.
Good luck with Your grow.

[Agentbuckwold3]

That's the setup and the plant in its current condition. Still growing rapidly, still green, and still very droopy. I've been able to get the res temp down to 69F-72F. PH has been between 5.8-6.1 right where it should be. I have no idea what's going on with this. Roots are still crystal white and healthy.

[Sheesh]

Is is possible the fan right next to the plant is hitting the leaves? I've had a plant droop like that overnight because a fan was hitting the leaves directly.

[Agentbuckwold3]

It was drooping well before I put the fan in. I've tried that fan in a few different positions and nothing changed. I'm leaning towards nitrogen toxicity at this point so I switched the nute water out with plain PHd water last night and I'm giving her a couple days to see what happens.