Three different experiences (which I’ve known existed) already that will probably set the pattern for what may come in further posts. For now, I’ll add a few comments based upon each point that strikes me. I may skip some points to avoid creating a treatise.
I do plan to maintain high range 8-10ppm initial PO4, just to inhibit GSA, but continue to wonder what beneficial stability might mean in a high tech tank. Is it keeping +/- 2ppm (via dosing throughout the week) or is dropping by 4-5ppm (from a weekly dose) by weeks end harmless? In some areas (NO3) I am gravitating toward the PPS approach, but believe that my too-great fish load will limit me in other areas.
Thanks for the input. I’m probably going to try maintaining a stable +/- PO4 level, breaking with my weekly dosing of that nutrient, since uptake of that clearly is something I can counter. NO3 uptake does not keep up with fish organics, so I will continue not adding any N for now.
Deanna I love your style … this is gonna explode.
“K, Mg and Ca can be high and left there”.
K and Ca yes, but not Mg.
Some are preloading 5 - 15 ppm PO4 and on top add 3 x a week 2 - 5 ppm PO4 when saturated plants can take only 0.1 - 0.2 ppm PO4 a day, hmmm.
You are asking about weekly versus daily dosing. Low to medium light will do with weekly dosing, but high light works better with daily dosing, tested and nothing new.
First, you don’t believe in studies
It’s a little scary that you have a fairly good read of me. You’re right: I am highly skeptical of studies thrown about to support one position vs. another. I think there are severe credulity issues that are created from the Internet. Such studies usually send me out looking for corroborating experiences from people I develop a trust in. So far in this post, that includes everyone that has posted. You mentioned that you’ve tested the daily vs. weekly issue in high tech situations. Did you document that process in any of your postings or website that I can take a look through?
I’m taking Barrs’ comment “K, Mg and Ca can be high and left there” not to mean deadly high, but just that weekly dosing works for these three, the word “high” being relative. I believe that there are upper limits to all of these before they become detrimental. I’ve seen comments and studies (uh-oh) regarding Luxury Uptake dangers, but view these as no different from any potential toxicities …stored or not. I am guilty of front-loading PO4 in your assigned high range, but it is purely to inhibit GSA which, I’ve found, it does. I haven’t seen any reports that high levels (5-15ppm) of PO4 either are toxic or inhibit uptake of other nutrients. I know I can burn my lawn with too much N or P and have come to believe that NO3 is better for plants in the 5-10ppm area in my tank (used to be happy with 20-40ppm).
My NO3 now starts the week at ~5ppm and builds to about 10ppm by weeks’ end. As mentioned, PO4 starts high and ends low. No dosing of either after the initial PO4 dose. Although my interest in this thread was about PO4 stability, I’m wondering if my plants are growing better at the beginning of the week or at the end of the week and does the varying PO4 and NO3 level impact this? Rhetorical question and possibly unknowable.
So the idea here was to get a more stable level of ferts throughout the week. Front end loading keeps mine stable because I have a large fish load. So between the natural creation of N & P and plant uptake, my levels stay very stable all week.
And keep in mind this depends on what theories you subscribe to. For my tank, I keep everything well above non limiting nutrients. Others have more success with very low levels of nutrients. To each his own and there are plenty of ways to manage your planted tank. It's figuring out which one produces the best results in YOUR tank that's important.
This is, exactly, the conclusion I came to in my overly-crowded and high biomass tank. Also agree with the uniqueness of individual tanks that, I believe, is the butterfly effect that we create by our individual approaches. I do think that we curve-fit our additives/water params (CO2, ferts, minerals and substrate) based upon certain critical aspects such as 1) quality and intensity of light, 2) fauna load and food, and 3) plant types and quantity. If you had @Edward
s identical setup of these three criteria, I believe that his additives approach would give you the same results as he gets and that he could match your tanks’ performance if reversed.
I abandoned pure EI some time ago, but with an eye toward maintaining non-limiting supplies. I do think that, for a high tech tank, beginners should follow EI. I now gravitate more toward @Edward
s lower thresholds for N, which seems, to me, to be the best flywheel to use to maximize – or throttle – growth while maintaining full health, but I do push PO4 well above EI and micros at the higher levels you and @burr740
I’ve been front-loading everything but micros for years, but am now questioning if it is actually creating significant detrimental instability, mainly the PO4 (for now), although I may end up playing with N if I move the PO4 and see positive changes. Thing is, I’m happy with my tank, but always wonder if there is just a little more that I might squeeze out of it.