Here are many of the posts by cavadge that I found of interest from my hydro notes word doc:
CAVADGE:
Forgive me for not being more specific. I've posted most of this in the past, and perhaps foolishly assumed people knew what I was referring to. Allow me to clarify...
I use Milwaukee Martini PH and TDS testers, with a conversion rate of 0.5. The PH pen cap is partially filled with storage solution to keep the probe wet. I calibrate the instruments every 10 to 14 days with solution.
The ratios I referred to were N-P-K. I began with 3-1-2 veg and 2-1-3 bloom based on a very old thread on another board by the fatman. Once I got hold of the nutrient calculator, it became clear that the suggested formulations of GH 3 part solution were nowhere near these values. So the journey began...
At this point I don't use GH Bloom at all. Only Gro, Micro, HW Micro, Liquid Kool Bloom, Cal Mag Plus, and Epsom Salt. Each of these pieces contain a different enough mix of elements that I can mix and match to give a good range of adjustment of the six main components - N, P, K, Ca, Mg and S.
Micro is the primary source of N. The two micros allow me to put the Ca levels where I want them. Regular Micro is 5% Ca, while the hardwater version is 1% Ca. I use a lot of Micro in the veg mix, so blending them gets the Ca number where I want it. I don't use Cal Mag in my veg mix.
The Liquid Kool Bloom is P and K, at a 1:2 ratio. This plugs in better all around than Bloom, which is why I don't use it anymore.
Gro has a lot of K and some N, so I do use a lot of it as well.
Most of the sulfur and magnesium comes from Epsom Salt. I have seen a definite improvement in overall plant health since I began using it.
Cal Mag is Ca, Mg and trace elements. Micro also has the trace elements - I use Cal Mag in my bloom mix to raise the Ca levels, as I'm not using as much Micro.
The other ratio I'm following, courtesy of this thread, is K - Ca - Mg of 4-2-1. However, whether it's my grow systems, strains, or envrionment, I have found better results with ratios in the vicinity of 3-2-1.
Below are the numbers and formulations I'm following. Now I suppose I'm rather backwards in my approach; I began with fatman numbers and just diluted the mixture to get the desired strength. So the actual concentration should be multiplied by the percentage strength being used.
I have a true aeroponic medium pressure misting system in use with my aerobuckets, which uses timed very short mist cycles and is a drain to waste system, as opposed to the aeroflo, a recirculating system. As such, I use a slightly weaker nutrient strength with the buckets. I am still improving upon my feeding strategy with the buckets; on my third grow now, better than before, but much room for improvement.
If I've learned anything, it's that the first 3 weeks of a clone's life when transplanted from the cloner into the grow system are the most critical and will determine the end result more than anything else. This is the area I'm addressing with the buckets.
The pictured plants were grown at a higher concentration, with a TDS around 800 to 900, and I noted some plants were showing deficiencies - at one point Ca (rust spots) and and at another K (browning along the edges). The current grow is using the same balance of nutrients but at a lower strength, and the plants are green and strong and have no signs of any problems at all. Most of us are aware of nutrient lockout, where too much of one element can inhibit uptake of another. But I've never been more aware of how easily this can happen than I am now.
As soon as flowering begins, I see PH drops in the aeroflos. They can be quite significant, sometimes requiring PH up additions twice in one day. The current grow, with a lower strength, is showing much slower and less severe drops, requiring PH up perhaps every other day.
This is significant, in that I'm using much less K than before, yet the plants are doing better and not showing any K deficiency. I can only conclude at this point that using a higher strength mix resulted in some Ca lockout at one point, and K lockout later in the previous grow. I now view this as less is more.
I should mention that I use RO water. Tap water would be a different animal, due to the Ca levels already in there. My tap water is too unstable for use in my grows.
At any rate, here are the formulae and concentrations currently in use, which over the course of about 9 months, have shown the best results. I use the same mix for both the aeroflo and the buckets, only the concentrations are different.
Nutrients are listed as ml/gal, except for Epsom Salt, which is in grams/gal. To calculate the amount needed for the grow system, I simply take the res capacity, multiply it by the dilution rate, and the spreadsheet shows me exactly what I need.
For example, the aeroflo is filled with 35 gallons. I want to use a 35% strength, so in the calculator where you plug in the res volume, I entered (35 X 0.35 =) 12.25 gals. This is the easiest way to change the strengh, by just changing the res volume.
LKB = Liquid Kool Bloom
ES = Epsom Salt
CMP = Cal Mag Plus
VEG
35% strength for aeroflo (TDS about 640)
30% strength for buckets (TDS about 460)
Micro - 12 ml/gal
HW Mic - 8 ml/gal
Gro - 2 ml/gal
LKB - 7 ml/gal
ES - 3 gms/gal
Per the nutrient calculator, this yields, at 100% strength, the following ppms:
N - 275
P - 83
K - 224
Ca - 180
Mg - 81
S - 103
BLOOM
As mentioned, out of the cloner, 2 weeks on veg, then switch to bloom for the last 7 weeks.
30% strength for aeroflo (TDS about 640)
25% strength for buckets (TDS about 460)
Micro - 10 ml/gal
Gro - 16 ml/gal
LKB - 6 ml/gal
CMP - 6 ml/gal
ES - 2 gms/gal
Per the nutrient calculator, this yields, at 100% strength, the following ppms:
N - 248
P - 88
K - 364
Ca - 183
Mg - 92
S - 69
I hope that explains where I'm at. Be happy to discuss further. As always, your mileage may vary.
I will post the rest of those guys "critical posts" later when I have some more time to dig... gotta go!
