Good info
@skunkd0c, thanks for writing. I agree down to the canna recommendation (H&G is just a canna clone but ime slighlty better). The socalled cannabis specific nutes tend to be rip offs but only if you buy the entire line, a couple of bottles or jugs of the base nutes are relatively cheap and can last a very long time. I spend about $20 per run and don't get a gram less then when I spend 4 times that amount. Fun at first, being able to mix a soup with so many bottles but after a while AB becomes the obvious choice.
I should probably go back to grasscity some day and thank the guy who led me to lower ppms. Funny discussion, I was doing a pretty good job defending 2.0 EC and higher with haelthy plants to back it up but the dude was right in hindsight. Skeptic as I am it took me 3 runs to lower the EC from 2 to 1-ish, ended up doing a .72 run ( half from tap already) after that just to find the bottom of the range and still got very healthy plants with the usual results, just had to add nutes more often. Hence 0.9-1.3. Convenient, safe, and plenty. Heath, Lucas, and several other hydro guys here came to the same conclusion. Based on system difference and amount of leaves it can vary and slighlty higher may be neccessary. Eg when you remove leaves th plants transpire less (easily observable in soil pots too), thus drink less water. If the nutrient uptake remains similar but the water level drops less fast the EC of the rez will drop faster. I also think that the speed of the water flow plays a role. Up to a point recirculating faster should allow for lower EC while still having plenty of all ions available at a given moment. Similar to how proper ventilation can be better for refreshing the CO2 depleted zone around leaves than adding high amounts of stagnant CO2 in the air. The contents of tapwater plays a role too which is not used up in an amount equal to the nutrient portion of the soup. Lighting affects both water and nutrient uptake as well and all these factors is why a system like NFT requires some dialing in, even if they were all the same AeroFlo system.
Not using bloom boosters or other additives high on one or more elements, but instead base nutes with good ratio, in combination with a not too large rez size that allows you to top off a good amount frequently should indeed avoid ever running into major imbalance. I started out refreshing every week regardless of usage and freshness, then I figured out if I don't dump my rez full with nutes and water, basically run with a smaller rez contents, I top off enough to avoid a complete refresh. I do think a weekly refresh is good practice for the first run or two. Just preventative.
Probably everyone who has grown mediumless noticed the improved nutrient uptake after a refresh. I try to keep that going by topping off with water and nutes frequently. It was the key to running as low as 0.72ec (which was a test and not what I recommend) as with such low ec the imbalance became obvious faster. I.e. When dropped to 0.70 after three days it appearantly still had a similar EC but undoubtedly a completely different composition, a different ratio with some elements more depleted than others. Ideally we'd be able to measure the npk and other elements in the soup and steer the ratio similar to the total amount based on EC. See Hanna photometer, $200 buck per piece and pretty much per element.
That turned out abit longer than planned...
the kush x cheese plant i was growing, was in a 20liter res, it ended up needing 12 liters per day to keep the water level the same
this is over half the total res contents, not a good idea if you only want to check on the plants every few days, but i am here all the time so it does not matter
during the hot months this helps keep the res cool as i am constantly adding cold water
the ph and ec would be fluctuating daily from something like 1.3 to 2.3 when the water level drops
as i am adding new tap water daily the ph would of most likely been now lower than 6.8 for most of the grow
i always add nutes based on ec readings, but now i think i will not bother adding any food unless the plants seem to be growing slowly
or show any slight deficiencies, i find that the food additions are very irregular, even with this plant that appeard to have a very even growth pattern through all of its growing time
some weeks i will be adding food maybe 2-3 times in the same week as the ec constantly drops points, other weeks i will not feed them at all as the ec never drops
because i have been keeping the ec lower i have been adding phosphoric acid a little more often
i add 4ml or so almost a t-spoon full every other week or when i can remember, i know i could stop doing this, its just habit
at an ec of 1.5 the nutes are acidic enough to bring it below the alkaline threshold, which is enough to keep them healthy
my starting tap water is 7.4 ph at .2 ec , the recommendation for these systems when they first came out was ec 2.0 ph 6.2
i used to keep it like that all the time, adding acid all the time to keep the ph constant, i would also change the res every 2 weeks or so
but i found all these things have no benefit
allowing the ph to drift along with lower ec has given me the same results
i personally do not believe the food is that important compared to the other variables
its the hydro that i can most relay on to work, i do not worry about it too much, as long as the pumps keep pumping
i dialed the system in , round about 1997 i have been repeating what works
my main focus is selecting new genetics as this makes the biggest difference overall
i am not interested in trying a new food unless it saves me money, or a bud enhancer
the tiny amount of difference it could make is not worth the effort imo, and i do not like spraying anything on plants
i do not think weed plants are big eaters, giving them growth regulators / hormones will cause an affect perhaps,
but a change in diet i do not believe it will do much for the price on the bottle of bud candy or whatever
for yield and size and such, water is just if not more important, like with soil folk try to provide more drainage
so they can water the plant more often without rotting the roots, making the wet/dry cycle quicker makes plants in soil grow quicker
with hydo the plants can drink huge amounts of water, i think this is overlooked as one of the reasons why hydro tends to grow larger plants in the same time frame
all of that extra water allows the plant to stay cool in higher temps, which also speeds things up imo
peace
