HALP! brown spots and yellowing

setup:
400w hps w/ cooltube
temps are steady 75-78 lights on, 65-70 lights off
humidity 45-60% depending on the day. I get air from outside so it varies.
ffof soil+nutes
using distilled tap water I water every 2-3 days feeding every other water. I've flushed both plants a few times hoping to get rid of it.

only thing I'm unsure of is pH, I was supposed to get my tester today, didn't show up. anyway, on to the pics...

I call her little one, she's been pretty steady the whole grow, just now showing these spots on a lot of leaves.


this is my big bitch, I have a few problems here... brown spots, yellowing, leaf curl, some leaves only have 3 fingers some only 1, I'm not sure that's really an issue, but its weird.



heres the new growth, only a few tops are doing that. any ideas?

Distilled doesn't have any minerals and not all nutes contain those minerals. So your plant isn't getting everything it needs. Either add some Ca/Mg supplement or just go with some straight up tap or rain water for a while.

you think switching back to regular tap water will help both problems?

Cal mag and or potassium maybe. http://forum.grasscity.com/sick-plants-problems/1115722-diagnose-your-deficiencies-here-easy-learning-table.html

i'd take care of the ph issue first and go from there. that one pic of the "very" yellow plant looks like an n def. really hard to diagnose a problem until you take care of the ph issue. ph is pretty up there on the importance chart, lol...

what size pots are those in?

the ph/cal/mag thing should be easy to solve with a little dolomite lime. probably a good idea to use the grow it looks like it needs some n/k.

also how close is the light, easy to tell if the yellowing on top is from lights some will have green shadows on them.

the big bitch is in a 3gal and the little one is in a 1.5gal. I keep the light about 10" from the top of the canopy

looking at that chart it seems the spots are only caused by Mn

and the plant is LST'd so would upper still only mean the leaves around the actual top of the plant or would all the branches that are now tops be the top of the plant? chart says yellowing at the top is S and Fe.

got my pH meter, but I didn't even think about that it's for soil only, so it's useless to test the pH of the water I'm using.... guess I'll have to buy a ph up and down kit too.

That is calcium deficiency for sure.

The fact that you are using distilled water makes it even more clear.

You need to add a calcium & magnesium supplement to your water before you add your base nutrients.

Or just use tap water.

that makes sense because I was actually using just tap water up until right before this all started. thanks guys, I'll try this.

ok bumping this thread since it's still on the same issue...

got my pH meter and my pH for the little girl is pretty good I think, 5.5

the big bitch however is a bit low I'm thinking, reads 5.0 on the meter but I've read that the meters aren't very good when the pH gets more alkaline so it could be more could be less I'm no scientist.

what can I add to safely adjust pH in soil??

If you want to get it up (pH) add lime to the soil. Really can't add anything to the liquid to do it that's good for plants.

Same exact problem im having with 2 of my girls... I just added lime to them yesterday and will hopefully see results tomorrow

They're looking worse now lol... im goin to try and flush then start nutes over again but i just watered recently so i gotta wait to flush >.< hope you're having better results.

well I haven't added anything yet... I'm probably going to give it a few days and re-test. I have one of the cheaper meters for sure, so I want to be as sure as I can about the actual pH before adding things.

Cheap probe pH meters are just that, cheap and inaccurate. Most studies on them have shown they aren't even accurate to the nearest point, which is suffice to say quite a bit considering that the next point up or down in the pH reading is 10x more acidic or alkaline.

What soil mix are you using? it's a good idea to amend peat based mixes with dolomite lime at 1-2 TBS per gallon of mix before you start. The lime not only helps buffer the substrate pH but adds calcium and magnesium to it as well. pH issues in the substrate aren't the easiest problem to fix in a short amount of time and really need to be measured accurately in the first place. Sounds to me like once you switch from tap to distilled water your issues started. I would go back to the tap water and check the new growth.

using fox farm's ocean forest. I added a bit of perlite for extra good drainage.

tested soil w/ meter again today, soil was pretty wet for first test, so I thought that might change the results. tested w/ dry soil today and took 2-3 readings per plant.

both plants seem to say 6.0 just about on the money... until I see something drastic change I'm not adding anything.

this is second watering back on just tap water. there isn't much new growth since they're so far into flower but they look happier in general since I've switched back.