Ca deficiency?

[Mañ'O'Green]

Well, I'm only repeating the hype Advanced Nutrients sold me on about the ph. I was absolutely having huge ph swings before. Using a calibrated bluelab ph pen, my ph is going in at 6.5, drifting up to 7.0, which I know is not ideal, but the magic of chelates and buffers and blah,blah,blah. No point using ph perfect and trying to adjust the ph. Before, using Flora I was getting truly hammered with ph drops. Starting at 5.9, drifting to as low as 4.5 in 8 hours! Which believe me, I know is a problem. I'd bring it back to 6, but over 4 hours in an attempt to lessen the shock. Tds starts 700 ppm, dropping to 550 overnight. Gets as low as 380 (yikes), topped up with either full or half strength nutes, mixed according to manufacturers directions (other than being half strength (8ml/gal)). Reservoir changed at least weekly, and i know i should do it once ive added back half the water (even that is pushing it) but that only takes 2 days, and im not changing it every 2 days. Just not happening. AN says equal parts Micro Grow & Bloom. Doesn't seem right to me, but I figure they know better than I do. Previously, I'd blame most of my issues on ph swings. I'm going to put these nutes to the test and hope they live up to half the hype. Generally I aim for 5.9 in veg, 6.1 in flower, but let it drift from 5.5 to 6.5, then bring back to 6.0 But this overloaded dwc is basically unmanageable otherwise. I'm dedicated, but I can't stay home 24/7 to monitor ph. I definitely bit off a lot to chew with this rdwc and leds. Growth is phenomenal, but soooo touchy.

Mix up a 5 gallon bucket of your current weekly nutrients ~40% strength. Use this to top off your reservoir. Keep it aerated. The PPMs in the bucket should be about the same as you started with for that week.

When I ran DWC I adjusted the PH at least twice a day.

Hydroponics is not for a lazy grower.

 

[Jovinn]

How could adding 40% (or even full strength) bring my ppm back to starting? If I start at 600, it drops to 400, I add back 600 strength, it won’t bring it back and it will continue to go down. Adding back full strength has been leaving me around 350 by day 5.
Dwc is definitely not for the lazy. Although I’m dedicated, I can’t be home always. Hopefully the pH perfect will perform as advertised, although at half strength it’s starting at 6.6, ending up at 7. They claim they’re still absorbable, I guess we’ll see.
Aeration I’ve got plenty, and thanks to you guys I got with the hydroguard early. Definitely saved me there. And I shouldn’t have gotten greedy , and tried to jam 9 plants into a 50 gallon rdwc. The level drop between buckets is pretty bad. I really just wasn’t expecting them to get this big. 3rd day with calmag added. Nothing yet, but at least didn’t make it worse.

 

[Jovinn]

Well, after listening to the podcast with David from Green Sunshine, its obviously light stress. Never had a fucking calcium problem from the beginning (maybe the light stress messed with the Ca, which is why it looks just like it?). Which makes sense. I'm not using coco or RO water, I've never needed calcium in twenty years. Now all of a sudden? NO. It's because this is my first go with LEDs. It wasn't light "burn", maybe not phototoxicity, but absolutely, positively light stress. Not bleached, but with the lights on 22 hrs, I obviously blew past my DLI. Being from the world of HID, I've never been able to light stress a plant. Clearly leds deserve a bit more respect and care. The symptoms:
1: psuedo nute burn (which I was getting at like 350 ppm, and only on upper leaves. Made no sense, because it Wasn't over fertilization.)
2: yellowing. Which again was baffling, as it looked like N def, but then with tip burn?
3: spotting: which looks Exactly like CA deficiency.
Which was my original question.
And so now, the thrilling conclusion...... NO. It was NOT a Ca deficiency. It was TOO MUCH LIGHT. I believe when Man O Green shot that down, he was correct in that it wasn't Toxicity, just stress. The INTENSITY wasn't harmful, the total amount was excessive. I'm guessing that all that light causes it to grow until it hits some Minimum (perhaps calcium? Thus the spotting?), then suffers deficiency. Also explains the reduction of symptoms following the increase in Co2. All makes sense finally. This grow is probably a wash, but at least I'll be able to make a bunch of rope! Not sure if the awesome power of dwc helped them cope, or stressed them even more.But:
For next time:
1) DWC with pH perfect. I am addicted to the incredible performance of dwc. The pH swings were killing me. Hopefully this will at least help.
2) space them Way, way out, and top. I don't know what I was thinking, trying to cram 9 plants in a 4x4 footprint. Dumb.
3) respect the DLI. I've never in my life had More light than I could use. I was warned, but now that I've been personally bitten on the ass I will be ever vigilant for the signs of light stress. Although I have Co2, I don't use a dehumidifier, so I can choose high vpd or high Co2. I went with vpd. Should have reduced the light as well.
4) auto flowers are pretty awesome. Despite all my blunders, I'm very impressed. I can just imagine if I hadn't gotten in the way.
5) Never again bother with calcium. All I need is already in the nutes and tap water. Total red herring.
Well, problem solved! Thanks everyone for your input, and I hope this can help someone else. The take away: if you get spotting that kinda looks like Ca deficiency, and you're not using coco or RO, it's PROBABLY NOT CA deficiency. Could be too much light. Nice problem to have, once you're aware of it.

 

[Mañ'O'Green]

How could adding 40% (or even full strength) bring my ppm back to starting? If I start at 600, it drops to 400, I add back 600 strength, it won’t bring it back and it will continue to go down. Adding back full strength has been leaving me around 350 by day 5.
Dwc is definitely not for the lazy. Although I’m dedicated, I can’t be home always. Hopefully the pH perfect will perform as advertised, although at half strength it’s starting at 6.6, ending up at 7. They claim they’re still absorbable, I guess we’ll see.
Aeration I’ve got plenty, and thanks to you guys I got with the hydroguard early. Definitely saved me there. And I shouldn’t have gotten greedy , and tried to jam 9 plants into a 50 gallon rdwc. The level drop between buckets is pretty bad. I really just wasn’t expecting them to get this big. 3rd day with calmag added. Nothing yet, but at least didn’t make it worse.

Your plants should be using more water than nutrients if the VPD is correct. So when you add a 40% blend you are assuming the plant only used 40% of the nutrients from the reservoir but all of the missing water. We are adding more water back than nutrients so we do not exceed our starting PPM in the reservoir.

This is all fine and dandy but we do not know which nutrients the plant used? We are adding back in balanced nutrients but the reservoir can be getting out of balance. This is why we do weekly reservoir changes because we know exactly what is in the tank!

 

[Jovinn]

If they were using more water than nutrients, my tds would be going UP, not down. I’m no mathematician, but for simplicity:
Begin with 10 gallons 10 ppm.
Drops to 9 gallons, 9 ppm.
No way in hell you’re getting back to 10 ppm adding anything that’s not MORE concentrated. Adding a gallon of 4ppm would lower the concentration even more. I’m pretty sure there’s calculators online that figure it precisely, I’m just sticking with topping off with 100% unless the drop is drastic. I’ve realized the “pseudo” nute burn is really from light stress, so adding even 200% has been tolerated well. And changing res every five days. Yeah, I probably should do it even more than that, but I have to set some limits. The people trying to grow without changing their res baffle me. Balance is key. And yes, my vpd could be a bit better (though generally pretty good, 75-85F, 55-65 %rh), but I’ve been trading a bit for co2 supplementation. I’m just not going to run a dehumidifier, so if they eat more than they drink, so be it. Within reason.