To top off or to not top off the res mid week with TDS?

haole420 · Dec 3, 2012

devolv said:
really? can I get some links please?

basic plant psysiology from biology 101: osmotic potential, active transport, etc. google it. there's plenty out there.

unfortunately, this article doesn't have a lot of references, but the guy has a PhD and is a professor and retired genetic engineer. it's a good primer article to get your head wrapped around how root absorption works. while he talks mostly about soil, the principles are the same for hydro, as we're still growing a terrestrial plant.

http://plantcellbiology.masters.grkraj.org/html/Plant_Cellular_Physiology4-Absorption_Of_Mineral_Nutrients.htm

Murphio · Dec 3, 2012

devolv said:
for an 8 week strain it costs me including mid week dosing. about 160$ for a 15 gal res each week. putting in a 200gal res would increase my nuts costs proportionally. a 200 gal res with my nutes would run 1435$. big difference in money spent per cycle. If I was using a different nutrient then, sure, maybe. I like my nut line so i'm not going to be switching soon.
another thing. this whole npk in the res thing. you're assuming that the plants feed on npk at a constant rate. I don't think this is true. I think npk is consumed at independent rates. still just adding base back to it has the potential to cause one of the less consumed compounds to become in excess. thus causing lockout.

$160 each week!!!!! I hope that was a typo. And to clear up any speculation you may have, plants do not feed on any nutrient at equal rates. Topping off with feed water should not create that much excess of a specific nutrient to cause lockout unless your pH is way out of range, or your ppm"s are too high in which case you shouldn't be topping off with feed water anyway.

devolv · Dec 4, 2012

Murphio said:
$160 each week!!!!! I hope that was a typo. And to clear up any speculation you may have, plants do not feed on any nutrient at equal rates. Topping off with feed water should not create that much excess of a specific nutrient to cause lockout unless your pH is way out of range, or your ppm"s are too high in which case you shouldn't be topping off with feed water anyway.

Yeah that was per cycle. Sorry

To top off or to not top off the res mid week with TDS?

haole420

Active Member

Murphio

Well-Known Member

devolv

Active Member