Seedling Day 10, and something is going wrong ?

Doing a DWC, grow pod bottom at water level directly above bubbler, Light 18 on, 6 off (Kind LED), 460 mmol, chamber temps & RH = 82F 60%RH w/light, 74F 75%RH light off, water temp 69F, pH 5.7 - 6.0, TDS 335 Seedling has sprouted third set of true leaves, ten days in chamber. pictures show two days ago, then today. Had been dropper feeding from the reservoir below the plant. resv had 25% rec amount of boost & grow. When true leaf set one started turning yellow (day , I lowered the plant about an inch into the reservoir for 12 LED light hours(day 9). Back above water level today.. see attached pictures.

I'm just guessing here but your feed might be a bit too hot...
I only measure in EC (ms/cm), and if i've got the conversion correct, that gives you an EC of 0.5, which whilst not crazy, might be a bit too much for such small plants in DWC.

What are you feeding them on?

Also I'm not an expert, just my observation based on my limited experience with DWC.

I had 25% of the recommended General Hydroponic BOOST & GROW. I dumped the water yesterday, and refilled with RO water, then reduced the pH with GH Ph down (buffered phosphoric acid) No nutrients added yet. TDS =77, EC 152, ORP 293. pH = 5.92 / water temp 71 F.

Plant holder cup/pod is in the bubbling aerated water about 1", leaving 2" above the water level. Plant is still drooping badly, same leaf set yellow. 2nd, 3rd, and now a fourth leaf set are green but droopy. Still totally puzzled as to why the plant took this turn downward in it's second week in the chamber. Don't know if it needs more/less food ?, water ?, oxygen ?, light ?

Unless anyone else chimes in, id back off on the feed, you say you were using 25%, back it off to about 12% and see how you go.

Once the roots are touching the water, you don't need the cups/net pots under water, the roots will grow and find the water on thier own - thay may have too much water if the whole of the root pots are submerged.

In terms of oxygenating the water/nute solution, what are yu using, air stones/ are you getting a decent amount of bubbles?

Right now I have zero feed, seedling pot just above the water level, so long tap root is in the water, and all the other roots have sprung out of the little cup, but are above the bubbling water. Bubble picture attached. Have to figure out how to send a clip of the bubbling action

Looks overwatered

Seems like there is not enough root structure actually getting into the water in my opinion. However, I see you posted that the water is just below the root plug, so it could be that you need more space between the water and root plug so that it doesn't over-water it accidentally.

pic shows root structure today.. long root has always touched the water.. the others are probably getting splashed by the bubbles.

Plant getting worse with no nutrients, as second leaf set now yellowing. TDS at 90, and pH settled at 5.9. Read yesterday that surface wave action actually oxygenates the water better than a bunch of bubbles, so I started some of that action on the surface and dialed back the intense bubbling right under the plant. Also read that the plant has nothing to feed on in RO water other than what was initially in the seed,,, and if starved, will cannibalize the lower leaves in an attempt to stay alive. Thinking I may be starving the plant, I added the 50ml of BOOST and 25ml GROW (both technaflora brand), which is ~80% of the recommended. TDS now at 980 (EC1960), ORP 275, salinity 1192ppm, pH 6.04

DaveT said:

Plant getting worse with no nutrients, as second leaf set now yellowing. TDS at 90, and pH settled at 5.9. Read yesterday that surface wave action actually oxygenates the water better than a bunch of bubbles, so I started some of that action on the surface and dialed back the intense bubbling right under the plant. Also read that the plant has nothing to feed on in RO water other than what was initially in the seed,,, and if starved, will cannibalize the lower leaves in an attempt to stay alive. Thinking I may be starving the plant, I added the 50ml of BOOST and 25ml GROW (both technaflora brand), which is ~80% of the recommended. TDS now at 980 (EC1960), ORP 275, salinity 1192ppm, pH 6.04

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Wat boost are you feeding please. From your picture and the water level it looks most of that net pot is submerged in water with a third probably not.

Technaflora Boost. Water level is currently being maintained at the bottom of the net pot to maybe quarter inch below the bottom. Dropper feeding the new nutrient water to the top of the net pot.

Dropper feeding from top...three days later.... The plant has survived and is thriving (day 17)... pH=5.9, TDS=1040 this morning. It seems that the all the plant needed was some food. Picture attached. Cut out a light blocking piece of black construction paper, and began adding some H2O2 yesterday (later tested at 25ppm), as the slightest bit of green algae had started to grow on the top of the grow medium, due to it seeing the grow light 19 hours a day. I'll bring it up to 75ppm today, and continue the top dropper feed which should kill the algae. Does anyone see a problem with that approach? So far I am keeping the plant roots from being submerged... ? should I raise the water level so that the roots can provide constant nutrients to the plant, or wait until the roots grow long enough to reach the water ?

Roots that age should be white and fresh. Do you have benies in the water, or are you sterile?

Roots appear OK (picture attached), and have grown as the plant has begun to recover over the past few days. Only boost and grow at 80% of recommended in the water (besides pH down, and H2O2 as of yesterday).... not sure what benies are, so I guess that the water is sterile ?

It's better to start the seeds in Pro-Mix/Soil before transplant them to DWC/RDWC. When the roots are brownish at the beginning, this is a nutrients build up and you should clean it under the sink with gentle hand massage. Also when you start seeds, it's better to use small 2Gal bucket instead of the 5Gal, you should wait at least the time you fill the 2Gal bucket with roots to make the switch.

DaveT said:

Roots appear OK (picture attached), and have grown as the plant has begun to recover over the past few days. Only boost and grow at 80% of recommended in the water (besides pH down, and H2O2 as of yesterday).... not sure what benies are, so I guess that the water is sterile ?

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Benies refer to beneficial bacteria such as Recharge or Great White or beneficial supplements such as enzymes that clear rotting material and make the plant hardier and more disease resistant.

Also, silica is also important in making hardy stems and full trichomes. Unlike benies, it must be added before the nutes with benies added last. Silica takes a little time to bond with the H2O so it's recommended to let it do the bonding for 15-30 minutes before adding nutes. I usually wait an hour or more after the silica.

IMO There are a lot of products to waste money on but silica and Recharge or Great White are essential.

One week after my last picture the plant appears to have recovered. I kept the started basket and the roots above the water/nutrient level. Changed the water and nutrients last weekend. Keeping H2O2 at around 50ppm.

Those roots looking a lot beter

Five weeks old today. Still keeping roots above water level, so feeding and watering are from what bubbles up in the pail. Let's call it fizz feeding