Software engineer grows (DWC) weed pt 2 w/ timelapse!

Yesdog

Yesdog

Well-Known Member
Has been two weeks since i reset the grow. The last attempt ended in failure, so with a few modifications this grow was sure to succeed (i hope). (more setup info from the first grow found here: https://www.rollitup.org/t/software-engineer-grows-weed-pt-1.916235/)

Seeds:
* 3x feminized Feminizedseeds Hula Haze
* 1x feminized Barney's Farm Amnesia Lemon
* (2x hula haze didnt germinate in the rockwool)
* Germinated in rockwool with 1/8 nute + distilled water, 1 week

Setup:
* Sealed 4x2 semi-outdoor tent
* 600w MH/HPS
* Self contained DWC 'bubbleponics'
* Time drip manifold, with extra waterfalls
* 3w air pump with 2 5" stones
* co2 injection
* 28g tote, 10-12g reservoir liquid
* Custom environment control/monitoring with: ph, co2, 3 zone temp, humidity, cooler, co2 injection, time-lapse webcam, graphing

Nutrients:
* GH Flora Trio
* organic microbe tea

Tea:
* Floralicious plus
* Earth Juice - Rooter's Mycorrhizae
* HydroGuard
* Age Old EWC
* Earth Juice - Hi-Brix molasses

Water:
* Tap water
* Meter: cheap shitty TDS meter
* slightly hard (40-60 ppm)
* 1 ppm chlorine, bubbled out 12-24hr






Week 1

day 0 - rez/equipment installed, 11g bubbled tap water
day 1 - seedlings in, 2g water + 1/5 strength nutrient solution added, lights 50% (172 ppm)
day 2 - start tea water
day 3 - start tea
day 4 - 1 cup 24hr tea, lowered lights
day 6 - 1 cup 48hr tea
day 7 - co2 injecting, lights 75% (172 ppm)

Stats:


Timelapse:
http://imgur.com/10TkCXJ (not sure why i cant direct link to my gif)



 
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Yesdog

Yesdog

Well-Known Member
updated the first post with more pics and link to timelapse
 
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Yesdog

Yesdog

Well-Known Member
Chef420 said:
Nice to see you're back up and running.
Click to expand...
KushyMcKush said:
Ive never seen a timelapse posted on this forum. Very cool. I love seeing people get creative!! Hope it works out for you this time.
Click to expand...
Thanks! Was super sad having to kill of my last grow, but this time it should be better!

The timelapse was a fun addition- I was just going to add a webcam in there so i can see them during lights on without venting the tent, but noticed i was only a day of work away from timelapse, so what the hell ;)

It's been pretty useful so far, at least as far tracking growth rate. Will hopefully be helpful in alerting me to issues before they get worse.
 
Yesdog

Yesdog

Well-Known Member
also for historical context, this is what's different for this grow vs the last:

* added pH probe to the arsenal and control system. Next grow i might add ph up/down doping, but so far it hasnt been really needed.
* covered reservoir with aluminum tape
* added iceprobe chiller (also controlled via the system)
 
Yesdog

Yesdog

Well-Known Member
in response to the poll on my last attempt, im going to try and clarify a few more points of the environment control. Today's lesson: CO2.

As far as how much CO2 and when, well... plenty of discussions about that around! But, once you have a target schedule/process, you need some way to trigger it. So here is the basic setup of my CO2 control:

Hardware:

* Existing custom environment control- a Raspberry PI in a tupperware box, surrounded by a rats nest of wires.
* AQUATEK CO2 Regulator Mini - uses paintball tanks, so much safer. If you're attempting co2 injection inside, i would DEFINITELY recommend a paintball CO2 vs a regular tank. The tanks are small enough that they really shouldnt provide a fatal dose of CO2 if something goes wrong. Plus the explosion hazard during fires is much less (but still there). Also depending on your area, paintball tanks might be easier to get refilled.
* paintball co2 tank - I have 2 so I can swap one out, so far I get about 3-4 weeks off of a single tank.
* sealed tent - gotta keep the co2 in!
* MH-Z16 NDIR CO2 - core sensor component thats hooked in my environment control
* Iot Relay - Enclosed High-power Power Relay - Basically a small outlet strip that I can turn on and off via the env control

Software:

The co2 controller is a component of the custom software for the env control. It monitors sensor data from the CO2 schedule, and reacts to certain configs and a schedule to open/close the CO2 solenoid. An ideal target is configured with these terms:

* min/max PPM - Opens when it hits the min or lower, closes when at max or higher.
* max injection time - maximum time it will inject CO2
* cooldown time - cooldown period after a CO2 injection cycle, allows CO2 to dissipate and lets the readings settle before acting again.
* schedule - a 24 hour schedule with a 'weight' for each hour between 0-9. 9 is 100% CO2 injection as configured, 0 is no injection, anything in between is some fraction of the above configured settings. This lets you 'ease in' and 'ease out' out of CO2 injection at the start/end of your light cycle.

I keep mine configured for min/max 1000/1500 ppm. This gives me a nice cycle between the 2 values during injection, averages about 1200 ppm. My injection time is 30s, cooldown is 60s. In my 4x2 tent, there's about a 15s delay between injection and measurement.

Other stuff:

pH - CO2 does drop your pH! It's very cool to see it actually happening as theorized. With my setup, the drop is maybe 0.2 pH, so not very noticeable unless you're graphing the trends really. On the bright side, it does go back up when the co2 is off. Just like a bubbling can of soda, the dissolved CO2 will try to equalize with the CO2 content of the air around it, eventually returning the pH to normal.

The sealed tent is really the biggest factor! If im in the tent doing maintenance the co2 will bump up to about 1500ppm just from me, and stay there for a few minutes. There will always be some dissipation, and that's fine. It just needs to be controlled to a point where its not wasteful.
 
Yesdog

Yesdog

Well-Known Member
day 9, roots touched down! I started to notice a bad smell from the rez and doubled down with more tea and some additional great white on day 8. By day 9, the rez smells perfect, and the roots finally touched down!

Anybody have an idea on what deficiencies they're starting to show? looks like N



 
Yesdog

Yesdog

Well-Known Member
day 16! Roots are all nicely established in the rez (8" drop), just changed out to full strength grow formula.

rez smells like a damn mushroom farm (before and after)- nicely established microbial life so far.

getting some algae on my RW, need to get collars on the plants once they're a bit taller.







last 4 days (days 10-16), touched down maybe 6-8 days ago.
 
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Yesdog

Yesdog

Well-Known Member
rez is pretty messed up- trying to figure out how to get rid of this extra precipitate at the bottom of the tank, so plants are kinda unhappy.

planning on replacing the rez soon as long as im sure i can get the precipitate out.

for now tho, foliar feeding the plants every day and just fim'd them today(maybe double fimmed? lol):

 
Yesdog

Yesdog

Well-Known Member
Ah, chaos, my old friend. Glad you could join us.

I had a pH misadjustment nightmare- the result has been this impossible to ditch precipitate at the bottom of my reservoir. I think the phosphate and carbonate buffers finally had enough, all out pH warfare has started.

Flushed the res twice with plain water to try and get rid of the carbonates- the issue so far is that lower pH seems to dissolve more... but any GH ph down I add just makes more precipitate....

I've decided to ride it out, replaced with a nice stable new rez mixture. The new rez bubbled away in my bathroom, and kept a solid 5.8 pH with only using humic acids. perfect. But, once my rez and the nasty precipitates got involved, everything went south:



I'm trying to find any other ph down that won't add phosphates- its pretty hard so far.

The plants are pretty 'dug in' to the system, there's no chance of moving em and scrubbing the main tank, so I'm just going to flush often and see if i can get through this.

Roots look really healthy tho after the flush (water is a bit pink now that the nutrients are back in):


You can see some spotting from the precipitates on the bottom and side. Fun.

Right before the rez crisis, I FIM'd the plants. They had a really hard time after that with the rez problems and the mutilation they just went through.

Growth is pretty scraggly (2-3 days of flush, no nutes), but they're pulling out of it. Will probably fuck my nodal spacing pretty good:


 
Yesdog

Yesdog

Well-Known Member
ph nightmare has ended! Finally got some sulfuric acid (10%) and it has pretty much solved all my ph issues. I flushed and pH'd 2 nights ago, really low (about 4.8 ) and by the morning it shot back up to 7- but all my precipitate was gone! It finally dissolved the bulk of it- changed out the rez, phd, and its finally stable!

So word of advice from a newb: if you notice ph down (or any phosphoric acid based down) seems to stop 'working' as well, switch acids (even if you do a rez change, the precipitates will still be stuck to all of your rez equipment- pumps, stones, filters etc.). Technaflora ph Down is mostly nitric acid which is a great choice, but its kinda expensive. Battery acid (or in my case, i just got the reagent grade sulfuric acid) is another strong acid that will work great to mix it up.

Here's a fun sorted solubility chart (from most to least soluble, 15 deg C) that should help you avoid precipitates/lock-out:

Calcium nitrate 121.2
Magnesium nitrate 69.5
Magnesium acetate 53.4
Magnesium sulfate 35.1
Calcium acetate 34.7
Magnesium citrate 20
Calcium sulfate 0.255
Calcium citrate 0.095 (25 °C)
Magnesium carbonate 0.039
Calcium phosphate 0.002
Calcium carbonate (Calcite) 6.17×10−4
Magnesium phosphate 2.588×10−4

Notice where the phosphates are on the list compared to the sulfates and nitrates.

New pictures soon, the plants are really really sad looking right now, but the roots survived just fine (still pearly white) so they should get back into gear soon.

EDIT: other word of advice- be careful with citric/acetic acid. It works great and gets a fast response, and there's minimal precipitates, but it takes forever to normalize (may swing from low to high over several hours). I would suggest only using citric acid (sparingly!) in your initial mix, and definitely let it sit for a night or so to see where its at (maybe use it to drop only half a ph). Also from what I've research, citric acid is best used BEFORE mixing in nutes as its a natural (limited/weak) chelator for Calcium- this should also help keep it more stable in the final mix, while protecting your calcium from other reactions. Probably most applicable to tap water.
 
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