DWC: Nutrient lockout or deficiency

I have some plants that are 9 weeks old that seem to be extremely vigorous in their nutrient needs. I record the PPM and the PH daily and have done some deep dives on this and everything I find is confirming that this is a phosphorus deficiency as I have some purpling of the stems, bluing of the leaves, brown spots followed by more intense leaf curling. The fan leaves most exposed to the light have the most symptoms though some newer leaves that are lower due to LST and receive less light show the same symptoms just less severe. Whenever I have increased my P nutes, the plants respond positively and the problem appears to stop for half a week after I religiously change the water every 7 days (using RO water with GH nutes, Hydroguard and CalMag). Last nutrient dose of N & P was 9ml/gal in a 5 gallon DWC and 6ml/gal of K, CalMag & Hydroguard. I've considered that this could be root rot but have examined the roots and they are not slimy and only appear to match pictures of being slightly tinted from nutrient water color. Root ends aren't as white tipped as I'd like but just at the far ends of the roots so I added another air pump with additional stones for more aeration despite each of the two DWC setups having a dedicated pump. It now holds 6 air stones in each bucket and is producing far more air bubbles for 3 days now.

Godfather OG
PH: 5.51
PPM: 2,360
Water Temp: 67F
Air Temp: 70-75F
RH: 30-50%

Chiquita Banana
PH: 5.51
PPM 1,990
Water Temp: 66F
Air Temp: 70-75F
RH: 30-50%


I feel like this could potentially be a salt build up simply due to the high PPM but every time I add another dose of phosphorus mid-week by 5ml/gal, both plants respond positively. Several days will go by and I will run into this problem again. It has been re-occurring for several weeks now and I don't want to harm my plant by flushing it if it's already deficient. Thanks!

UPDATE:

I ended up going with a flush for 48 hours and started the nutes back up again at 3ml/gal for NPK & CALMAG & 2ml/gal of HydroGuard with fresh RO water. The discoloration had stopped spreading and the plants look better, though they never did look terrible! PH for both reservoirs is now 6.22 with the PPM 450-500. Color looks great and plants seem to have accelerated growth!

Thanks for the great advice through other post on this site!

Due to the popularity of this post... J/K!! Just updating the pics, girls are doing great!! Switched to flowering a couple of days ago!

In hydro, flush and fresh nutes works ~95% of the time.

And normal ec level... good job turning it around

Thanks! First grow in over a decade and first ever hydro! It's pretty damn easy!

SnoopyDoo said:

In hydro, flush and fresh nutes works ~95% of the time.

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What exactly do you flush in hydro? Lol

Hollatchaboy said:

What exactly do you flush in hydro? Lol

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the bad juju from the reservoir. think he means emptying the res and starting new

firsttimeARE said:

the bad juju from the reservoir. think he means emptying the res and starting new

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Lol I know what he meant. I was just giving him shit.

Hollatchaboy said:

Lol I know what he meant. I was just giving him shit.

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I got that same treatment first time I said it. Lol

But all kidding aside, is not letting the roots sit in RO water without anything any it not flushing the plants? From what I've read, it removes the salt build up in the roots putting PPM back into the water flushing it away from the roots. If that's not flushing, what do you call it?

Alctrz8849 said:

But all kidding aside, is not letting the roots sit in RO water without anything any it not flushing the plants? From what I've read, it removes the salt build up in the roots putting PPM back into the water flushing it away from the roots. If that's not flushing, what do you call it?

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That's called starving the plants

DaFreak said:

That's called starving the plants

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Then there are a ton of people using the words "flush" for "starve" on this site then, I've only found "starving" now that I've done a search for it, but everyone in that thread calls it flushing too.

Alctrz8849 said:

But all kidding aside, is not letting the roots sit in RO water without anything any it not flushing the plants? From what I've read, it removes the salt build up in the roots putting PPM back into the water flushing it away from the roots. If that's not flushing, what do you call it?

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Pretty sensitive word around here,perhaps we need to come up with another term?
Like taking the ladies to the spa? lol.

Alctrz8849 said:

Then there are a ton of people using the words "flush" for "starve" on this site then, I've only found "starving" now that I've done a search for it, but everyone in that thread calls it flushing too.

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Flushing is a term misused all the time. Flushing is trying to wash out built up salts from a medium. If you have no medium then you aren’t flushing. But yes, there are tons of people who starve their plants.

myke said:

Pretty sensitive word around here,perhaps we need to come up with another term?
Like taking the ladies to the spa? lol.

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Hahaha!!! By gads methinks we have a winning phrase!!!

After I took my ladies to the spa, they never looked better!!

DaFreak said:

Flushing is a term misused all the time. Flushing is trying to wash out built up salts from a medium. If you have no medium then you aren’t flushing. But yes, there are tons of people who starve their plants.

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Ah, the technical info my mind craves!! Thank you!!!

Just thought I'd provide an update with pictures! All is well and I played Mr. Deville and got a close up of my ladies!

Look good. About 18 days? Or are they from seed?

How do you flush yourself when you are sick? Lots of pure water. Push toxins out. Eat later.