deficiency showing up week 6 of flower...under current

Ph is typically very stable as is drop in ppm when under 800ppm.

Room is 76* +- 4*
Rh is 46-55

Lights could be further if I had the height but don't think that's the problem, shouldn't be wind burn either as it happens on spots with little wind.

Im thinking it's either
Improper imbalanch of nutes (calmag/ A/B ratio)
Not enough calmag or a/b

@redi jedi says hes using 800 and under with no issues... Any idea what my problem could be man?

Like I said I use around 250ppm calmag on 0ppm water, and around 500/550 a/b

Is that ratio off? It seems like could be a deficiency from not enough a/b compared to the calmag issue

@redi jedi I change my res every 14 days but the guys at the shop or just telling me I should be changing it every 7 days and they think that's definitely my problem. How often do you change your res?

Thanks a million!

I change out once the ph reaches 6.3. In early veg that could be a little over a week. In late flower 4-5 days.

I dont correct ph at all during the week. I adjust it once after mixing a fresh batch and thats it.

So in late flower you change the entire system every 4/5 days is that right?!

Maybe that's exactly my problem, I'm going 3x longer (14 days) than you...

Do you use boost? Im assuming not because that would get pricy real fast changing the system that often...

Thanks @redi jedi im gonna start changing the entire system every 6/7 days to see if that helps!... You think that's my problem?

Slimjimham said:

@redi jedi I change my res every 14 days but the guys at the shop or just telling me I should be changing it every 7 days and they think that's definitely my problem. How often do you change your res?

Thanks a million!

Click to expand...

We change ours every week like clock work with a water top off every day veg and flower with Ph levels 6.0 and above.

We use a concentrate up and down which controls levels longer than the basic brands. Basic brands are made of a handful of different chemicals and breaks down much faster than concentrates especially in hydro system's.

Hmmmm so maybe the 2 weeks was too long... Again current culture says you can go 14-21 days before changing res's... Maybe bad info from them?

Im guessing maybe the plants took up more of some salts than others and made an unbalanced res that was locking things out after a week... or the soup just became deficient in some elements.

That's what I didn't get, how could I be deficient on such a basic mix of 250ppm calmag, and 550 ppm canna a/b....

Everything they want should be there but sounds like over time that changes...

Thanks, you guys think we figured it out? If so I would be beyond happy!!!! Im guessing you guys change the nutrients weekly for a reason!

Though plants always look great till week 5/6 flower so maybe they just don't have so much demand on the nutrients in the res till week 5, then weekly changes are a must as they are way more p,k hungry? Does that sound right?

Our ph levels change due to uptake. As the plant eats the ph levels change accordingly, ph chemicals used to adjust also break down and then there is always evaporation which doesn't take heavier salts.

I would suggest water/nute changes every week through the entire grow, and finding a nute system that has enhancers designed to stimulate growth at different stages of both veg and flower. Your plants will reward you for it.

Slimjimham said:

So in late flower you change the entire system every 4/5 days is that right?!

Maybe that's exactly my problem, I'm going 3x longer (14 days) than you...

Do you use boost? Im assuming not because that would get pricy real fast changing the system that often...

Thanks @redi jedi im gonna start changing the entire system every 6/7 days to see if that helps!... You think that's my problem?

Click to expand...

Yes, fresh nutes weekly...approx.

It very well could be your problem. I'll get minor issues(necrosis/rust spots) if I Iet the ph go over 6.3

The only additive I use is pk13/14 and I only use it for the one week...as the directions recommend.

Is it only the buds right under the lights?

Are you running the undercurrent in sealed room? what are your Co2 levels?

Roots have and always were in great shape.

Whay I found worked best was only topping with RO water, changing the tank weekly.

Ppm starts at 400, dips close to 200 by changeouts every week..

This solved the issue... so thinking it's prob just that I need to run super low Ppm in my system...

but switching everything over to rockwool... it's a plant count killer but im able up get much higher quality with less input from myself it seems

Keeping the undercurrent systems to Veg mothers! It's great for that!!