Ph dropping, EC rising, water level dropping conflicting advice

[Cinejeff]

I am getting conflicting advice and could use some guidance.

I have a Kush in 4th week flower that is drinking close to a gal a day in a 5 gal bubble bucket. Plant stands about 5 feet tall, did some defoliation about a week into switch. Now I’m noticing that the PH is dropping daily, starts at 6-5.8, dropping to 5.2 or lower. I’m feeding her the Lucas formula - GH nutes (micro/bloom 1:2 ratio at 700ppm+ tap) and EC is rising (1200ppm+) in the remaining red water. No signs of burn or deficiency but I think I’m catching early enough. Been just adding regular water, tap is about 160ppm to start.

One group says increase EC as it is leaching nutrients from roots to reach equilibrium the other to add just water to lower EC as it is just drinking water and not needing as much nutes.

Plant seems happy, thoughts on which way to go?

 

[Airwalker16]

I am getting conflicting advice and could use some guidance. One group says increase EC, the other to add just water to lower EC.

I have a Kush in 4th week flower that is drinking close to a gal a day, PH is dropping (starts at 6-5.8, dropping to 5.2 or lower), feeding Lucas formula GH nutes (micro/bloom 1:2 ratio at 700ppm) and EC is rising (1200ppm+). No signs of burn or deficiency but I think I’m catching early enough.

Plant seems happy, thoughts on which way to go?

Rdwc, flood and drain, drain to waste?

 

[Cinejeff]

In a 5 gallon bubble bucket, about 5 feet tall. Roots look great, massive root ball, two air stones

 

[Airwalker16]

In a 5 gallon bubble bucket, about 5 feet tall. Roots look great, massive root ball, two air stones

It's because you're dealing with such a small volume of water.

 

[Aqua Man]

Water doesn't leech nutes from the roots and it's possible you need to lower your nutrient concentration.

I would suggest a res change. Ph dropping could indicate some root problems but first can you post info on nutes and how you do water changes, top ups and mixing?

But before doing anything there are several reasons so let's start narrowing it down.

Please add some pics of the roots of you can.

 

[Aqua Man]

When you add back water each day how much is your ppm going down after adding back just water.

I just reread your post. A little hung over today :/ . Im pretty sure your ppm are to high. I have no idea of the growing conditions you are in so can you please post that info also. It will give a good idea of what sort of ppm you plants would likely need.

 

[JohnDee]

Your EC is too high, case closed.

Yup...plant is using water faster then nutes...ec rises. Lower EC.
JD

 

[Cinejeff]

Here is a pict of the roots, they are stained a bit from the nutes, especially the raw kelp. I’m using lucas formula using GH flora bloom 15ml/gal, and micro at 7.5ml/gal to about 700ppm + tap. Start with tap water at about 150ppm. Use NPK Raw kelp, cal mag and silicon additives sparingly. I keep ph at 5.8 to 6 and change res completely every two weeks, top up daily with 700ppm nutes with about 1/2-3/4 gal. Lights are actual draw of 500w using led quantum boards. In veg it took it all, res ph would rise, ppm stable. At about 2-3 weeks into flower I noticed Ppms rising and ph dropping. Today at res change it was 1200ppms and ph 5.2. Did just water last two nights, ppms pretty much same story. Was 1400ppm two night ago

 

[Cinejeff]

Here’s a pict of the plant, it stands about 5 feet tall, maybe a bit more. It’s a blueberry x purple kush strain. Very fragrant, Uber fragrant actually.

 

[Aqua Man]

Yeah it over fed I would drop to max 800 ppm and top using 1/3 nutrient strength so like 250ppm.

 

[Cinejeff]

Did a res change last night, drank about a gallon, ppms dropped from 750ppm to about 600ppm, ph stable at 5.8. Added lighter nutes at 550ppm with a little NPK RAW kelp extract for good measure. Seems to be back on track, idk what what going on but I suspect maybe the lowering PH was licking something out. Going to run it closer to 6.0 with less Ph down to keep P lower, week 5 of flower so will prob feed a little extra K this and next week.

 

[Aqua Man]

Did a res change last night, drank about a gallon, ppms dropped from 750ppm to about 600ppm, ph stable at 5.8. Added lighter nutes at 550ppm with a little NPK RAW kelp extract for good measure. Seems to be back on track, idk what what going on but I suspect maybe the lowering PH was licking something out. Going to run it closer to 6.0 with less Ph down to keep P lower, week 5 of flower so will prob feed a little extra K this and next week.

Use your add back to steer the ppm and ph.

 

[MoodyShoes]

Res change, lower EC.

 

[fartoblue]

How did this work out for you mate? I know it is an old thread but I have been having similar problems.

I have gone with this advice from a UK forum, seems to make sense.

Here is a post from Woody J taken from a UK forum.

I think it can be very confusing what to do when you have what appears to be nutrient burn, the automatic response is to lower the EC. However, generally, this just makes things worse.

The key to understanding what is happening is the water levels as I mentioned. If they are more or less static when into flower, something is wrong. The issue then becomes what to do about it?
Increase or decrease EC?

Once you understand how plants roots work, the answer is obvious.
They work in a very similar way to an R/O machine. So nutrition will flow from the higher EC to the lower EC in a reverse osmosis process.
Which means, if your EC is climbing, you need to increase EC to a level that stops it rising.
If you have hard water over 0.4, it may mean feeding with an EC as high as 1.8-2.0. This is something I wouldnt normally advise in DWC.

However, if you keep in your mind that a "normal" EC of 1.2 usually brings decent results in DWC, this should be the nutrient level on top of background EC.

With both guys who have had issues who contributed to this thread having high background EC's, I think this is the source of the problems. So being brave will pay dividends.

Remember, the key to this is what is happening to the water levels.
Good luck guys.
W

 

[Cinejeff]

In my case I did a res change and that fixed my issue. I then fed it a higher ppm and noticed no burn, bumped up again and it loved it. Ran about 1200ppm right to flush. Got 320g of great bud off that one plant.

 

[Busternutt]

Similar story for me. My pH drops, EC climbs and I'm starting to get burning on leaf tips. I'm using an ebb and flow system. The plant is in perlite in a 15 litre pot and the reservoir is 15 litres. I have been changing the reservoir every week and since about week 3 of flower, have needed to top up the reservoir every second day and now, it's using around 2 litres per day. I am due to change the res tonight which will begin week six of flower.

What is the correlation between the amount of water "drunk" and the pH going down and the EC climbing? Is this the most likely cause of my tip burning?

 

[Airwalker16]

Means your over feeding. Add water to your res. Or if you're going to change it, nearly halve the PPM in the next batch to what it reads now.

 

[Busternutt]

Means your over feeding. Add water to your res. Or if you're going to change it, nearly halve the PPM in the next batch to what it reads now.

Ok, ta

 

[Renfro]

 

[Busternutt]

Thanks Renfro

I changed my res last night and while I didn't halve my EC, I did lower it substantially and also lowered the pH. Not quite 24 hours later, the plant has drunk a litre, the EC has risen a little bit and the pH is the same.