Day 23. 13/14 Early vegatation. Need some advice. I have already went through support and they said everything was fine and lined up with recipe. Plant is still growing. Leaves have developing spots and dying off within days. I have already trimmed off bottom two sets of leaves at the direction of support yet it still continues to be seen on new leaves. Temps have been steady inside box with light on around 75 degrees and humidity 45-50%. Water temps 69-71 degrees Fahrenheit. Distilled water used.Roots are white and plentiful,no signs of root rot. No signs of dampening off either. Only additive I am using is hydroguard. pH is steady at 6.0 with check and manual meter. Modifiers to environment are humidifier in room, tower fan on outside, supplemental fan inside, and second air stone in DWC. The pH probe has already been checked and is calibrated. Unit was also thoroughly cleaned and sanitized between grows too.The first two pics are when all this started and third one is today. Also root pic included. Any ideas? @chris_barfield @Todd.grobo @Russel_Richardson @Bplatinum9 @vegetato @SilverGrobo
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(All I can think of is the Extra additive might not be working with the dosage of Grobo nutrients):
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Given everything else you’ve checked, this appears to be a calcium deficiency – it’s either not drinking enough of it for some reason (aka “nutrient lock out”) or there just isn’t enough of it in the water for it to drink.
What do the fluid levels on your bottles look like, specifically bottle #5 – is it less full than #3 & #4, the hose isn’t kinked or something, is it?
If bottle #5 does seem to be dispensing also have a peek at bottle #3 & #4, are either of these two higher or lower than each other and what is their level in relation to #5 (there should be less of those two used if they were equal at the start of the grow). Marking the current fluid level with a marker on the bottle (regularly/weekly) might help to rule this out but it takes a few weeks to collect the data.
To add to that last response – doing another drain/fill might help, as it would let the unit take another shot at releasing the nutrients. If for some reason too much of bottle #3 or #4 was released or not enough of bottle #5 was released then a drain/fill (with new water, not the same water) might help to rectify that.
The first thing to do before assuming it’s not dispensing properly is to figure how much is actually being dispensed, so again mark the bottles with a marker and again an hour or so after each drain/fill (it takes the nutrients about 15-30 mins to dispense after filling).
How much hydroguard do you use?
I use 3 teaspoons in my fill water once a week.
Also like @vegetato suggested please do a complete drain and fill and mark your bottles before hand, keep posting so we can see the daily change and hopefully we can catch the problem. Dont give up yet!!! Let’s work together to see if we can save this grow!
I put 5cc Hydroguard which I left out in drain and fill yesterday and nutrients are dispensing properly. I always mark bottles with each drain and fill.
You seem to be doing everything right!
At this point I would recalibrate and refill to be safe.
Did you use a brush and cleaner to clean probes last time?
P.s. Try switching your water to 60% Reverse Osmosis & 40% Distilled.
It is calibrated and yes I used brush to clean probes
I say recalibration because often the probes can get clogged or dirty at any stage of your grow and need to be recalibrated.
I know how frustrating this can be so using process of elemination can sometimes save your grow. 
You may end up needing to consult with @Stephen, to see if recharge or extra cal mag needs to be added temporarily.
Can you post a pic of bottle 5?
By the way, I was using 12mL of hydroguard with each of my drain/fills. I don’t think there’s any harm in adding too much unless you’ve got the smaller-sized bottle and even then that’s probably still quite a bit for our purposes.
It is mentioned on the label that it should be used up within 6 months of opening, so 6 months of doing 1x drain/fill each week (and one dose of hydroguard) would mean that you use up 120mL in that period if dosing 5mL each time. I have two grobos, and still can’t go through a 960mL bottle in that time even when I use 12mL on each drain/fill. I’ve also used two bottles for a bit longer than 6 months and in both cases it did seem less effective once it got old enough.
I do wonder, though, if perhaps the hydroguard itself uses (read: steals) some of the calcium from the water. That’s beyond my current level of knowledge but would be my hypothesis if no other (more obvious) reason is determined.
Thanks, using distilled water it should have dispensed more than that at this point (typically it is almost even in usage with bottles 3 & 4). Wondering if there is a problem with your EC probe. I agree with @vegetato this looks like text book Cal. deficiency and the low usage of bottle 5 really backs that up.
Also, when are you adding your Hydroguard? Before or after the grobo dispenses nutes/cal-mag?
Adding hydro guard before nutrient dispensing. I have revive on hand if needed.
Hydroguard is to be added after nutrients and cal-mag (Same goes for all additives & beneficials aside from Silica which is to be added about an hour before you fill your reservoir to allow it time to “bond”). Go ahead and do a drain fill with plain water and then add your Hydroguard directly to the reservoir after grobo has dispensed bottles 3, 4, and 5. I don’t think this is your issue but it is worth a shot. Do you have a manual meter to check EC in your reservoir?
I don’t have a manual EC meter
I’d recommend ordering one from BlueLabs, great tool to have. Also, go ahead and administer 6mL of Revive prior to adding hydroguard.
Either your line is kinked or calibration is off as suggested earlier.
Your plant is only defecient because its not getting the cal mag from bottle five that it should be getting.
Calmag deficiency or lock out … flush her with water … unplug the nutrient bottles except for ph bottles and flush her overnight or atleast four hours … then request a ph adjustment to 6.0 …