Dwc problem

[Akabudz]

Hi all, I am new here,
This is my first grow in 15 years. Setup as follows
Dwc 40ltr tote, nutes and water filled to 20ltr.
2 x white widow feminised from seed, scrog. Approx 8 weeks veg under cfls
Switched to 1212 under a 250w hps 14th April all was well when I started bloom nutes, fast forward upto 2 weeks ago and all my top fan leaves turned yellow,
Ppm 800-900, Ph 5.8-6.3
Temps 28oC, rh 25-40
I lost most top fan leaves as they turned yellow and brittle.
My problem is now for the last week they seem to have stopped growing. Please take a look at images below and let me know how you think they are doing.
Thanks

 

[Akabudz]

P. S in my 2x2 tent I have approx 28 main bud sites, and all colas are pretty much the same height at around 14inches

 

[Akabudz]

Would you go lower ppm? Maybe give a flush first?

 

[Akabudz]

Bump.

 

[CosmoGrows]

Hey @Akabudz, i grow in soil and have never touched DWC. I'm not the one to help in this case, but i know @Aqua Man is very experienced in DWC. Maybe he can provide you some help on the DWC side of things.

Best of luck man. Your plants do look good aside the issue you're having.
- Cosmo

 

[Akabudz]

Hey Cosmo, thanks for dropping in, I look forward to hearing from the dwc guys

 

[One drop]

Hi I think it’s a sign it maturing getting ready to be harvested but as the moderator said the other moderator man will shed some light on subject , where is that moderator man ..... Od

 

[Aqua Man]

Roofing today just seen this. Looks like they were previously overfed and the switch to bloom nutes likely cut a little to much nitrogen and may have a slight K deficiency. If using bloom nutrients I feel waiting until after stretch to switch to bloom nutes gets you closer to the finish you want.

how often are you changing the water and how much a day are they drinking? The K deficiency may have to do with an imbalance.

Source of water

600-700ppm should be plenty

 

[Akabudz]

Thanks for dropping in guys,
They get full res change every 5 to 7 days, I would say they are drinking 1 gallon evry 2 days, I checked ph and ppm last night and ph was 6.1, ppm 840 so they seem to be taking water and nuts approx at equal parts at the moment which they havnt done for a wile.
I use tap water, ppm straight out is around 190ppm, next grow I may go ionised water.
I will get some better pics this evening after work. I will also drop the ppm as suggested,
Thanks again for taking a look mate .

 

[Aqua Man]

Thanks for dropping in guys,
They get full res change every 5 to 7 days, I would say they are drinking 1 gallon evry 2 days, I checked ph and ppm last night and ph was 6.1, ppm 840 so they seem to be taking water and nuts approx at equal parts at the moment which they havnt done for a wile.
I use tap water, ppm straight out is around 190ppm, next grow I may go ionised water.
I will get some better pics this evening after work. I will also drop the ppm as suggested,
Thanks again for taking a look mate .

Keep ph 5.6-6.0 I find anything over 6.0 would start giving me some small issues. It's a 40litre system?

 

[One drop]

There you go moderator man on the mission ...

 

[Akabudz]

Keep ph 5.6-6.0 I find anything over 6.0 would start giving me some small issues. It's a 40litre system?

Yes it's a 40ltr tote, I will keep an eye on ph and drop a little when needed, thanks again bro.
Ohh just one more question.. Is 20ltrs in a 40ltr tote enough?

 

[Aqua Man]

Yes it's a 40ltr tote, I will keep an eye on ph and drop a little when needed, thanks again bro.
Ohh just one more question.. Is 20ltrs in a 40ltr tote enough?

I'm sorry I must have read it wrong. Water line just below the net pot. Once you add back 100% of the volume of actual water you need to do a res change if you go longer it can create a nutrient imbalance over time. As the plants get bigger they will need more water changes. So you have about 5 gallons of water, if they are drinking 1 gal a day you will need to do water changes every 5 days at the longest. If they are drinking more than you may need to even do them more often than that.

 

[Akabudz]

Thanks bro, would it hurt for me to add another 10 ltrs of water? There is quite a gap between water and bottom of the net pot, Or are the roots set to that depth now? Hope that makes sense?

 

[Akabudz]

I check ppm and ph daily, some times they take more water than nutes so I top up with PhD water, some times they take more nutes, then I bring ppm up again all Phd.

 

[Akabudz]

Just got in from a 12 hr shift, I will check them shortly

 

[Akabudz]

OK.. This is not good, just checked ppm 750, ph 6.0, adjusted to 5.8, then noticed all lower leaves are turning yellow as in image ((
All that changed is I added an extra 5 ltrs of water yesterday to bring ph up after I took it too low, so res was higher than normal, that is the only change I made, does raising the water/mute level effect anything? Have I covered air/oxygen roots up? If that is possible?

 

[Akabudz]

I'm sitting here going through my notes and just noticed my main top fan leaves went the same not long after I changed them from 2 x 10ltr buckets to 1 x 40ltr tote, again with a different water level... Could this be the problem I am having? Some sort of lockout as roots that were previously above water level now submerged? I have just dropped 5 trs of water out out of res just in case.

 

[Akabudz]

Any one?
Thanks

 

[Beowuuulf]

My first thought was ‘light burn’

Looks Nitrogen deficiency Pics on google