Yellow spots badly dwc +pics

Yellow/rust spots eating away at leaves there in a dwc setup roots have not touched the bottom 71-75 room temp...18c res.....ph 5.5..... 1 ml 35 h2o2 per gallon <<< I think that might be it)......Just cleaned res due to white snot looking stuff and 75 temp.. This is my last attempt and then I'm thru. don't know whats wrong? I've read magnesium/calcium but I don't want to feed and screw it up worse nutes were gh 3flora series 100ppm before res change pics below

seriously 56 views and no reply's at all wow

First thing you need to do is get your water temps down. With a res temp of 75 you're going to keep having problems regardless of what else you do.

hydrogreen65 said:

First thing you need to do is get your water temps down. With a res temp of 75 you're going to keep having problems regardless of what else you do.

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I did the res is about 65 at all times..I doubt that's what is causing the leaves to turn rusty I think underfeeding or overfeeding/ph nutrient lockout could be the problem although the Ph is constantly checked for consistency its been about 5.6-6.3. I been doing everything by the way I am reading it on these forums with the same results/is there anyone that knows what the yellow rust spots mean early on sorry my camera sucks but the leaves have become worse. could using h2o2 have something to do with it?? because I use it all the time. I highly recommend soil for beginners if your reading this.

Only time iv eva had rust spots is tiny little ones caused by spider mite. But ud probably notice them as soon as u checked, little black dots underleaf.

Don't panic, they're very young, you have plenty of time. Flush them with ph'ed water (5., raise ppm's to 250. maybe foliar feed with horticultural epsom salts to counter any poss mag/def defs.

Why your last grow?

First off your Ph is low! Get the res up to and hold at 6.0 (5.8 - 6.2 is ok). Higher not good but lower IS worse!

Stop the hydrogen peroxide use now! Put an air stone connected to an air pump into your res. Better yet use a 2 line pump and use bolth. Peroxide just evaporates from the mix in less then 24hrs...

The plants show stress from low Ph and CalMag dif. The low Ph is contributing to the Cal Mag,,but you are low on that too. You don't need to flush just yet.
USE G&H CALiMAGic at 5ml per gallon of formula in res. !!!! (the CALiMAGic is low N and contains some extra iron and you need that right now too)
FEED THEM....don't get flustered by what they look like right now. You have along way to go and this is an easy fix!!!

Be aware that the old leaves will NOT repair themselves. What I mean is this; See a problem - make an adjustment - see results in new growth!
In soil it takes 5-7 days to show a correction.
In Hydro it takes around 3 days to show a correction.
You will only see the "fix" in new growth from the top of the plant.

Soil has it's own problems for a beginner, like taking longer to just show a problem and then longer to show the correction....
In hydro, if you start out with a proven formula you will have a better chance at your goal (in soil too).

A simple rule of thumb would be like.
Pick a nutrient and follow the manufactures instructions...ALWAYS ad a CalMag product. (It's easy to stop if need be) and a good zyme helps root health in hydro more then most think.

You and the girls will be fine. Trust me. Fix Ph, add a Cal Mag product (stay away from epson salts for now) and in about 5 days you'll see recovery!

Good luck