fartoblue
Well-Known Member
Many thanks for taking the time to read this thread and giving such a detailed and informative response, it is really appreciated and apologies for taking so long to get back.
I will be putting some new plants into this system in a week or so and will implement everything you have suggested.
Nizza is correct! Control the res or buckets to under 70 but not below 65 F. This may have been a problem as I did take the aquarium heaters out and the res temps went as low as 55 F during lights off.
pH... STOP allowing that pH to drop to 55 - AS BEST YOU CAN... This is better controlled by setting the pH to 6.2 or 6.3 in the mourning.
I know many who like low pH in hydro BUT, it is easy for it to lead to issues...just like yours. ESPECIALLY SINCE THE pH SHOULD BE A CPL OF TENTHS HIGHER IN BLOOM! Your way to low for blooming cannabis in hydro.
Rule of thumb in hydro applications for pH values... 5.7 to 6.3 The common quality book scale is 5.8 to 6.2.....
Part of the above issue is likely a habit of not dumping and starting with fresh nutrient mix properly. The other side of that coin is how much in concentration your adding back to "top off" the tank or buckets... I do think PH fluctuations have been a big problem especially low PH and obvious (classic) signs of calcium deficiency. PH has always dropped and has been below 6 for most of the time. I did PH up to 6 most mornings but it would drop rappidly to as low as 5.4 overnight. I have had rot in the system but not this time (at least not in the roots but there may still have been pathogens lurking in the system)
Waste build-up from the plant effects the ability of the mix in the bucket to work properly.. I have been thinking about this and it could be the problem. The system recirculates but the inlet outlet for each tub is around 3 " from the bottom and the nutrient level 5" above.
I may put an elbow on the outlet from the tub so it pulls from lower down and increase the recirculating pump size to give it a bit more movement. Could some nutrients be heavier and sit in the bottom of the tubs unused??
I will also put a mesh filter on the outlet that runs into the epicenter. Maybe also flush more tap water through the buckets to mix with the residue in the bottom of the buckets and then drain again, realistically I have only been doing partial change outs maybe just over half.
Lets take a look at a simple solution to that. "The 33% add back rule"
This is an old school, original hydro rule that still works well today! This could also be a big problem I have been adding back at full strength or more although I do feed quite low 1.3ec - 1.4 full bloom with a 0.2 background, 3 feeds per day. I generally add back plain water for the last few weeks before harvest and amazingly the PH becomes stable. My most dramatic PH swings are at around 2-5 weeks into 12/12. This is also when the calcium deficiency shows up followed by dry crispy dead leaves all over the tops.
Fill your res/bucket with your 100% feed solution. Note how much in volume you filled it with.
Now as that res/bucket reduces in solution, you add back to top off,,,correct? Keeping track of how much your adding back..
You should be adding back a 33% concentration of that feed solution and not 100%...
To make a 33% solution: Simply take a gallon of the 100% solution and add two (2) more gallons of plain water to it. You now have a 33% solution.
Top off using that 33% solution.
Now here's the other important part. Remember I asked you to keep track of how much your adding back?
Now when the amount you would add back comes to equal the amount you filled the res/bucket with the first time.
DUMP AND REFILL WITH 100% SOLUTION and restart the whole topping off with 33% all over again. This really does make sense and it is something I have never heard of before. My plants seem to drink quite a lot then almost stop.. It is as if they are not transpiring and drying up yet my humidity (40 - 50) and temps (18 night - 24 lights on) are perfect with lots of air flow.
Do this in veg AND bloom!
Lastly: Mixing
Add each chemical after adding an amount of water.
EXAMPLE: Your making 3 gallons of 100% mix.
Add 4 cups of water to your mixing container.
Add the first chem by pouring the next 4 cup scoop over the measuring cup with the chem in it.
Rinse the measuring cup (I use a 60ml mini cup)
Now do the same for the each chemical you add. ALWAYS ADD THE CAL/MAG LAST.
Now pH your solution and use it. Most times I do it like this apart from I add the Botanicare cal/mag first to get my water to 0.5ec. Occasionally I add directly to the epicenter.
I get the distinct feeling your not dumping and refilling enough and are suffering from hydro waste build-up.. I do think you may be correct as everything seems to start off so well (12/12) and then go downhill.
This sure won't hurt you, so give it a big try out. I most certainly will, and will update with the results.
Good luck! And good luck to you my friend, many thanks.
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lol
Is it true what I've been reading that they're not really approved by your legal customers over there?