Phosphorous deficiency, right?

[WooksGoneWild]

Hey guys, relatively new grower here and just would like a little confirmation on my hunch. I'm at work right now, and will update with a full plant picture tonight.

Problem: Suspected P deficiency

Medium/grow method: Rdwc

Feed: and supplements used: megacrop 1g/gal, sweet candy 1/4 tsp/gal, Hydroguard at recommended dosage.

water source: tap, dechlorinated

Strain/age: Forum Stomper, Mephisto approx. 3 weeks

light used: Spiderfarmer Sf2000, 30" above

Climate: 74F air temp, 65-67F water temp, 60% RH

Additional info: I suspect P def, just based on self diagnosis threads I've read - symptoms being reddish stems, blotchy rust spots, perhaps water temp too cold, thus slowing uptake of phosphorous.

I've since raised my water chiller temps to a range of 68-70F, and I've added an additional .5g/gal of Sweet Candy. I'm pushing nearly 2,000 lph of air through 10 stones, to 2 per bucket, and 2 in my reservoir. Have beautiful white roots, no concern there.

Base water TDS approx 90ppm
Base water PH approx 7.2
previous TDS 330ppm,
Current TDS 390
Highly stable PH of 5.8-6.2

thanks guys, I've lurked a long time here and read tons of threads. I hate that my first post is asking for help, but it is what it is and I'm glad to actually be joining the community.

 

[WooksGoneWild]

After 24h of upping my pk booster and raising water res temps, I am thinking this may actually be a cal deficiency.

Thoughts?

Update: Did a res change, figured I was under feeding and went with 2g/gal of Megacrop. Ph set to 6. No PK booster.

Update: Additional 24h later, Megacrop does is now about 3g/gal

PH 6.0
EC 1.0 / TDS 550

 

[Waira]

-- Wooks, it looks like P defc. to me too, maybe not the typical presentation I'd say,.... almost looks infected... Plenty of Ca in MC,symptoms don't match Ca defc. well either... Take a couple normal light pics for me when you can, COB/LED is lousy for assessment,...
Definitely light on feeds before, and MC is weak on P as is,.. You're pretty rich now at 3g/gal, pH is good,... no PK boosters yet you say? What do you have, Bud Explosion? You could swap some of that in, maybe even make a weak solution for a foliar spray. You'll need a wetting agent for that, or mild soap like castille, use just enough of it to stop the solution from beading up; this lets it coat and stick better... Also spray undersides of leaves, way more stomata there vs. topside!
Meantime let's see what the elevated ppm's do,...

 

[WooksGoneWild]

Thanks for reaching out Waira, this has been stressing me out for the past 2 or 3 days. Here's some good pics without my lights on.

I've got Sweet Candy, not Bud Explosion btw.

I didn't wanna go full strength in nutes because my other 3 plants in this rdwc system germinated 6 days slower than this girl so they're lagging way behind in growth and o was worried about killing them.

Also, MC is quite low in nitrogen right? Like, it's quite hard to burn plants with it period I think I read somewhere. And it's also quite hard to burn with PK, right? I'm going to see how they like the higher PPMs, and if it doesn't look good in the AM, I'm thinking of adding 1g/gal of Sweet Candy.

Again, thank you.

 

[Waira]

...have you checked her roots? I should have aske that first...
....I'm still thinking P defc., though Ca defc. can present similarly,... MC has plenty of Ca so I doubt it's a lack-of at least... When's the last time you calibrated you pH meter, BTW? If not stored in the right way, with proper solution, and calibrated fairly often, (never let dry out) it can be knocked of enough to give you very bad readings... in hydro, P availability is very bitchy...
SC has no P in it mate, read the label,.. a ton of K though... BE is their PK booster, but it too is very K heavy, so if you use BE and SC, you need to be very careful about total ppm's and the heavy K load... Also because of all the stuff that's in MC, it's ppm values are somewhat inflated compared to other nutes that are just the basics in primary, secondary and micronutes.... So, 400ppm of MC is not as rich in basic nutes as a more simple base nute formulation would be... Yes, you surely can burn with any synthetic nutes, organic too it's just harder...
No, MC is N rich, and too much for bloom phase IMO,.. no other brand of nutrients is even sorta of close to this amount... too much N makes for more leafy, airy buds than is typical for a given strain...
It takes some time for things to take affect, symptoms to slow and halt... give it a couple days, meantime really hammered leaves may croak out anyway...

 

[WooksGoneWild]

Really appreciate the breakdown Waira, I'm going to give it some time and see how she looks.

I calibrated my pen a few days ago, it's a blue lab ppm monitor, I just let it sit in my reservoir.

I'm gonna order some BE, just to be safe.

 

[Waira]

:smoking: Cheers Wooks!

Hmmm, I'd not let the TDS meter sit in such solution, it may shorten its life from potential corrosion, seepage into the non stainless tender parts! Bets to rinse with pure low ppm water and store dry...