not enough nutes?

Never thought I'd be asking this one, but for once I think I don't have enough nutes rather than too much! My plants are about 40 days old from seed and I'm seeing yellow bottom leaves and necrotic crispy leaves on a few of the plants as well. The yellow leaves say nitrogen deficiency and the crispy/necrotic leaves say phosphorus deficiency. Plant growth also seems to have slowed down in the past 2 weeks.

This is a hydroponic DWC setup. I've been keeping nutes at 800ppm with an NPK ratio of 5 - 10 - 9. PH gets adjusted daily to 5.5 and creeps up to 5.8 every day. From what I've learned, if PH constantly rises the plants want more nutes. From what I've read here people are encouraging hydro growers to not use full strength nutes and this is the 1st time I'm trying that approach, but I'm getting the feeling that these plants are stressing and am trying to figure out why.

I have 2 strains going: Nirvana's Blue Mystic and Mandala Seeds #1. I have 2 #1's, which are the tallest and look very healthy other than yellow bottom leaves. The Blue Mystics are the short ones with necrotic/crispy leaves on the bottom (as well as yellow leaves). Some of the BM's are downright stunted-- 3 inches high when they should be at least twice that. I've not grown BM before, so don't know whether this is typical of the strain and if the stunted ones are just dwarfs or something. They're supposed to be similar to Northern Lights and either mostly or fully indica. The #1 is 75/25% sativa/indica and a real winner in my opinion from experience in past grows. Hardy, great yield and great smoke.

Anyway, here are some pics of the plants. Please let me know if you care to guess what the problem(s) could be!

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Hey man
Just raise down your ppm about 400 ppm ( your nuts should feed around 300 ppm nuts with out your water) ...
Your plants showed u by lower ph day by day and u did some wrong...
Use some Cal mag or epsom salt for your lowering leafs
Bst wshs

Thanks, not sure what" raise down your ppm 400" means, though (raise up the nute levels or lower them down? can't do both). I've done previous grows at 1400ppm while vegging without problems, so I'm sure these plants can handle higher nute levels if I need to go there. Haven't grown BM's before, but the #1's have taken those nute levels like champs in previous grows. I've had Cal-Mag problems in the past, it's just been a while so I don't remember the symptoms, just that epsom salts helped. I went ahead and added 1/2t of epsom salts per gallon in my nute solution. From what I've read that's about 1/2 the strength of what's recommended for hydro setups. This upped my TDS by about 300ppm, so I'm at 1260ppm now, which is higher than I'd planned, but again these plants should be able to take it. I'll just not add any of my regular nutes for a while until the TDS drops back to where I want it (in the 900's). If I continue to see problems I'll dump the nute solution and replace with a fresh batch. Let me know if you think 1/2t per gallon of epsom salts will be enough to see a difference if that's actually the problem.

you have multiple deficiencys...see the yellowing on top and bottom? that means theres an immobile, and a mobile deficiency...but seems like you have everything figured out.

Yo 40 days is almost 7 weeks that's a long veg stage,
How many ppms did you start'em with?
I'm thinking you been under feeding or something
hows the roots they cool. On the ppms this is
what I go by. It's Advance Nutes's chart but
the ppms are the same?

http://www.advancednutrients.com/hydroponics/nutrient_calculator_old/

All, thanks again for the feedback.

These plants are 40 days from the day I started the seed, some folks measure their plants' age differently . . . some start counting the day it pops up above the soil (or rockwool) and some give them an extra week or two as 'seedlings' before they start counting. Just to clear the true age of the plants up.

Either way, I agree that these plants are small and the only real thing different between this grow and the last is the lighter nute load. Last grow was same nutes and general setup but TDS levels of around 1200-1400 rather than 800. Roots are looking alright-- I have some old algae on the roots from before I light-proofed my DWC tub, but there is white root growth at the tips where the plants have grown out since then. Nute reservoir temp is 75 degrees, air temp is 85.

These plants started on nutes at about 2 weeks old, I worked up to about 800ppm over the course of 10 days. The plants have been at 800ppm since then. I'm using GenHydro macro and bloom at a 1:2 ratio (not using any grow nutrients). I just added 1/2t of epsom salts per gallon to add magnesium to the nutrient solution, which brought the TDS up to about 1200ppm. I'm guess I'll watch now and see if things improve with the magnesium. Not sure if adding more of the other nutes right now would be helpful or not, so I'll wait a few days.

It's not so much your PPM. Look at your NPK ratios. Low on N and probably Mag. Calmag them. Hurry. Hydro moves fast... including fuckups.

Alright, after stressing the hell out of my poor plants for the past few weeks, I've finally come to the conclusion that my ph has been too low, causing lockout and all the other problems my plants are showing. From what I'd read with the "Lucas Method", the target ph was 5.2, which is lower than I've ever run a grow before, so I was playing it safe and shooting for 5.5. I tested my PH meter out the other day and it had drifted a bit, so it was off by about .3 (so 5.5 was actually back at 5.2). I adjusted it and looked through notes on some of my old grows and found that my ph in those grows was usually between 5.8 and 6.2. I also changed out my nutes and went back to the "normal" Genhydro feeding schedule rather than the Lucas method. This increases N amounts slightly (2%), potash a bit more (6%) and magnesium (.5%). I also moved the plants to their larger DWC reservoir with about 25 gallons of nute solution rather than 2 gallons, so they have a lot more room and solution to work with. The plants' leaves have stopped yellowing and turning necrotic and falling off, and the healthy green leaves have gone from curling almost straight down to back to a horizontal position. Sad thing is that I noticed this leaf curl-- the start of my problems over 3 weeks ago and it took me this long to figure it out. Oh well, more experience for next time I suppose. Even though these plants are miserably scrawny, I'm planning to go ahead and flip the switch to start flowering them in a week or so. I'm hoping to get 2-3 grows in this winter and according to my original timeline I should have flipped these a week ago but was having so much trouble with them that I'd kept them vegging. Sure to get a sorry yield, but I'm hoping to take clones of the mandala #1 and will hopefully do better next time around! Moral of the story, ph 5.5 is too low (for me, at least) and the plants seem to like 6.0 much better.