Potassium Deficiency?

HYDROPONICS

How long has this problem been going on? Maybe a week, about when I switched to flower
Are you growing in a PVC grow tent? (example: Hydrohut or any other non brand tents)No, panda film tent over pvc frame
What system are you running? (DWC? Ebb flow? Aero? Water Farm? Flood Tables? and so on...) 3x6' flood table
What STRAIN are you growing?16 Chem D and 11 OG Kush
What was the establishing technique? (Were the seed or clone?)Clone
What is the age of your plants?4 1/2 weeks of veg and 1 week of flowering so far
How long have they been in there mixture they are in now?5 weeks(coco,soiless etc..)
How tall are the plants?Uneven canopy ranging from 2'-3'
What PHASE are the plants in? (seedling, vegetative or flower) are the plants in?Second week of flowering
What Technique are you using??
What substrate/medium are you using?(Hydroton, RockWool etc.)6" rockwool cubes sitting on hydroton
What is the Water temperature?60 degrees
What color are your roots? White? Brown? Are your roots slimy?From the ones I can see they look really white
What Nutrient's are you using?(If growing soiless)General Hydro 3-part
How much of each nutrient are you using with how much water? *Knowing the brand is very helpful* 350ml Botanicare Cal/Mag+, 325ml GH Grow, 650ml GH Micro, and 975ml GH Bloom to 70 gallon reservoir
How often are you feeding? (If using soiless) 3x per 12 hour light period
How often are you giving nutrients? (If using soiless) Drain reservoir once per week
If flowering, when did you switch over to using Bloom nutrients? Switched to full bloom-nutes yesterday, used transition phase formula for the previous week
What order are you mixing your nutrients? (example: veg nutes 1st, bloom 2nd ect) Micro first before giving a stir, then in random order
What is the TDS/EC/PPM you are using? Currently at almost 1500 ppm
What is the pH of the "Tank"? 5.5ph
Are you sure your calibration is correct on your equiptment? Ph calibrated daily, ppm calibrated once per month
When was your last watering? 7 am this morning
What is your water temps?60 degrees
When was your last feeding change? (ie. grow-bloom-micro-additional) Switched to full-bloom nutes yesterday
How often do you clean your system: example: Flush out water replace with clean water and nutrients? 1x per week
What size bulb are you using?1000w Hortilux HPS
What is the distance to the canopy? 10-20"
What is your RH Factor(Relative Humidity)? 71%
What is the canopy temperature? 72 degrees
What is the Day/Night Temp? (Include flucutaion range) 72 degrees day/62 degrees night
What is the current Air Flow? (cfm etc.) 449cfm Vortex 6"
Tell us about your ventilation, intake exhaust and when its running and not running ?Due to low temps when the fan runs constantly, I adjusted so that the fan only runs for 15 min/hour
Is the fan blowing directly at plants? Oscillating above the canopy
Is your water HARD or SOFT? IDK
What water are you using? Reverse Osmosis (RO)? Tap? Bottled? Well water? Distilled? Mineral Water? Tap water with 60ppm to begin
Are you using water from a water softener? No
Has plant been recently pruned, cloned off of or pinched? No
Have any pest chemicals been used? If so, What and When?Yes, had spidermite problems at week 3, sprayed neem/pyrethrin mix and hung a No Pest strip
Are plant's infected with pest's? No sign of spidermites or pests in over 2 weeks. Using neem 1x every 2 weeks to make sure they don't come back

The main problem is that it looks like I am having a potassium deficiency after looking through the Grow Bible. The plants look fabulous other than some yellowing and spots on some of the older leaves and it is not spidermite damage. Here are some pictures:
http://www.icmag.com/ic/picture.php?albumid=13323&pictureid=315952
http://www.icmag.com/ic/picture.php?albumid=13323&pictureid=315953

If its just the bottom old fan leaves they may just be too old. Leaves do get old and die after all, with some strains behaving different then others. You may never know what the problem really was/is.

Other than that the water may be a little cold for them.

Think about the shock that they may be feeling every time they get watered. The roots go from being 72f then have to drop a full 12 degrees when the table floods. I would add a heating element the bring the water temps up to 66f at least.

Have your feet to do that, and tell me how you like it.

Be well & good Luck

attila76 said:

If its just the bottom old fan leaves they may just be too old. Leaves do get old and die after all, with some strains behaving different then others. You may never know what the problem really was/is.

Other than that the water may be a little cold for them.

Think about the shock that they may be feeling every time they get watered. The roots go from being 72f then have to drop a full 12 degrees when the table floods. I would add a heating element the bring the water temps up to 66f at least.

Have your feet to do that, and tell me how you like it.

Be well & good Luck

Click to expand...

That is an odd recommendation since a lot of other people on here have told me to remove my rez-heater, and the problems seem to be happening since then. A lot of people have told me that rez-heaters decrease dissolved oxygen because of waters ability to hold oxygen decreases as temperature increases. I'm starting to think that there must be a middle ground that I need to find. And no, I do not enjoy dipping my feet into a chilly pool either hahah. Anyone with any second opinions? Thanks guys

Cheers!!!!

Yes, 60 degrees is too cold for ebb and flow. It will work, but will
slow down the growth and possibly cause other issues. It is true
that water has more dissolved o2 when it is cold, but that is not as
important if you're not keeping your roots submerged in the water
for too long, like in DWC or SWC. Throw an air stone in there or
another pump to circulate the water, if you want. Just by reducing
the surface tension you will increase o2. Hell, just the water moving
to the top res will create more o2. I keep my res at around 68-70 F,
uncovered the whole grow without changing my res and all that is
on the bottom of the res is fallout from the organic nutes they
receive.
A lot of people will tell you different things, you just have
to sort through all of it and figure out who's technique is closest to
yours and can offer the best advice. A lot of people would say I'm
crazy for never changing my reservoirs and keeping them
uncovered, but it works for me and that's what matters. I pull
about 750g's per month per 600W HPS per 8 plants in an E/F
using hydroton. Nutes are botanicare PBP, EWC tea, Magi-cal
only. Veg time is 12-14 days, LST.
Why would i change a res when the plants look fine? I don't
understand it. Big time waste of money and time. (A little off topic I know)

jim_browsky said:

Yes, 60 degrees is too cold for ebb and flow. It will work, but will
slow down the growth and possibly cause other issues. It is true
that water has more dissolved o2 when it is cold, but that is not as
important if you're not keeping your roots submerged in the water
for too long, like in DWC or SWC. Throw an air stone in there or
another pump to circulate the water, if you want. Just by reducing
the surface tension you will increase o2. Hell, just the water moving
to the top res will create more o2. I keep my res at around 68-70 F,
uncovered the whole grow without changing my res and all that is
on the bottom of the res is fallout from the organic nutes they
receive.
A lot of people will tell you different things, you just have
to sort through all of it and figure out who's technique is closest to
yours and can offer the best advice. A lot of people would say I'm
crazy for never changing my reservoirs and keeping them
uncovered, but it works for me and that's what matters. I pull
about 750g's per month per 600W HPS per 8 plants in an E/F
using hydroton. Nutes are botanicare PBP, EWC tea, Magi-cal
only. Veg time is 12-14 days, LST.
Why would i change a res when the plants look fine? I don't
understand it. Big time waste of money and time. (A little off topic I know)

Click to expand...

Not off topic...very relevant. Thanks for the explanation, I now put my rez heater back in at about 68degrees. Hopefully there aren't any other probs as well.