I think we all have that issue lol

Gerry,

I forgot to mention that P.S. is very sensitive to PO4 fluctuations as well.
When I kept this plant many years back it completely stopped stunting on me when I changed from pulsing PO4 every now and then to tiny daily additions!

Best regards,
Detlef

I have high PO4 and it has no issues.
I think running out of PO4/NO3 are two things that have strong stunting responses from fast growing weeds.

If you go from feast to famine levels, vs stable levels, whether they be small daily doses, or larger less frequent, but still high overall residual levels, then you have no issues.

This is true for most nutrients.

Maintaining low levels daily concentrations etc can be difficult for many, I think that maintaining higher levels is easier and more stable based on human habits.
It gives you far more buffer.



You can see you will have a more likely chance of dramatic growth related issues the closer you get to strong limiting values vs the wide range of optimal growth.

These ranges can be different for various species, not so much in the wide range of optoimality, rather, at those lower ranges of limiting growth(a and b).

It should also be noted, some slight limitation is not a bad thing is many cases, many aquarist want to limit growth. Limitation of growth is not an all or nothing response. Some plants respond with more tolerance than others. The shape of the above curve tends to to be more like this:



This is real data for corn and the application of N fertilizer on the foliar application vs soil uptake.

However, a far better and more practical method to do that is to simply reduce ligh time or intensity which can be adjusted far more easily and maintained at that level than nutrients ever can be. If stable levels of nutrients is truly a goal, then incorporation of both water column and sediment based nutrients is the wisest solution.

This gets around some of the trade offs with dosing the water column. However, now there's few methods to directly measure the nutrients in the sediment and removal via uptake available to hobbyist.

So they cannot test the sediments for the inorganic concentrations really.

There are some basic methods to test whether a plant does well however on a sediment and with good water column dosing(or not). Do the treatments, then measure the biomass before and after.

P. stellata is a rapid growing weed and will grow faster at higher light effectively.
Then you measure the before and after biomass.

Some plants will not make any difference. Some will.
However, once you add the human factor in there, folks skipping the dosing here and there, then you start to see declines.........

Every single aquarist I know slacks off and forgets to dose here and there.
We all over look something at some point.


Regards,
Tom Barr

Detlef and Tom,

Yes, I am dosing EI a bit heavier lately as my bio-mass is increasing rapidly and the stellata appears to love the conditions

3 tsp N and 1.5 P 3x a week is doing well for me now. About 70 ml of TMG.......Running juicy as Tom says....

450 watts of MH about 20" about the surface.

With my c02 now adequate, I am experiencing excellent growth on all plants.

I doubt I could remember daily dosing lol

So far so good.

Will post if any issues, but anticpate NONE.

Thanks again for all of the great info!

Gerry, there is a good reason to do daily vs 2-3x a week mentally: you feed the fish daily right?

Same with the ferts.

Takes a second etc.

This works well if you feed your fish daily(which many do not, many do not even many fish in there). So you can tweak things a bit more this way.

If you want further tweaking with nutrients, then you add ADA AS or something similar with macros in the sediment as well as water column dosing.

However, as is the case 9X out of 10X, CO2 bumped up as plant biomass increases, helps.

Ask yourself why this might be the case with P stellata?

What habit does it have that would lend itself to rapid increases in CO2 that can be tapped out quickly?

Rapid weedy growth.

So as plant biomass increases exponentially............so does demand for CO2.
If you where adding say 20ppm at a rate of 4 bubbles a second , now after 2 weeks, you might need to add 7 bubbles a sec to keep the CO2 at 20ppm.

If you have high light under those MH's, then this plant will grow even faster.
Now ask yourself this same question with another plant, say Anubias coffeefolia?

Would you predict the same response to CO2?

No, I would not.

So large factors include : the species involved in the tank in question, the routine for pruning it back to maintain the same relative biomass over time, making sure the CO2 is constant for the biomass, and good current as more biomass and current and inversely proportional.

Now apply these changes through time with nutrients.
Will dosing say 1 tsp 3x a week give the same response to Anubias filled tank vs a stem plant tank? High vs low light? Poor CO2 vs high CO2? Fe limited vs non Fe limited? Low current vs high current? Pruning often vs not much?

Aquariums are not single variable systems and most have a really rough time isolating things to tell anything about single variables. Many things covary.
Our minds miss a lot of things that we think are not important, but when made are, appear obvious and logical.

Still, aquariums occur in time and space. Making sure the parameters and physical conditions stay the same is not always easy for our habits.

See if you can feed the plants on the same routine as the fish.
If not, go back to 3x a week. Also, setting up a set of powders or spoons etc that are easy to access and use daily is wise.This makes the likelihood that you will dose etc more probable.

Same deal with a water change system. Some folks have sets that they can dial their cell phone and do a water change while in another state. I like easy to use semi automated systems.

I like to be involved but lazy. Automated weed whackers are hard to design and make though I guess I'll have to hire a kid to prune

Regards,
Tom Barr

Tom,

All that you say makes sense.

Due to a recent substrate change, I have been doing 50% wc every other day for the last 4 weeks. I have also been concentrating on good c02, current/flow, adjusting lighting, etc as I have been re-reading dozens of threads

and I have BEEN DOSING every day as well as a result, since N and P on wc day and trace the next......

I forgot about that in my excitement (and pleasant surprise) that the plants were doing so well. DUH!

Like, no wonder the growth is suddenly magical.........

So, my results support the daily dosing and your comments here:


I intend to continue dosing on a daily schedule, as I can clearly see a difference.

Question: Can I dose daily, but keep a weekly water change? I can go twice a week if I must, but that is more than I want to do. It's the same amount of nutes I am dosing, just spread out over more days, no?

I am also really seeing that you have to really pay attention to the overall BALANCE of light, current, fish load, plant species, nutes, etc.


Where can I get one on those??? lol

Mine is a bit manual, but not too much effort...

As always, thanks for taking the time to respond and teach.

Gerry,

Not sure what they sent me, but it wasn't PS, as far as I can tell. Looks like a hygrophilia with leaves that are green on top and purple on bottom (leaves are shaped like h. angustifolia). I thought at first it might just be the emersed form of PS, but I really doubt that -- it looks like a totally different plant.

Anyway, I'll see if the LFS can order it for me.

Ted,

I understand that the plant my look different based on collection locale.

Give it a bit to grow and should be easier to id.

Yeah, I'll give the new plant a try ... once it settles in, I'll post a pic here and hopefully someone can ID it.

Two types, a broad leaf type that Dave Wilson collected from a natural system in northern Australia, then a narrow leaf type that's fairly common. I like the narrow version.

You can do the daily dosing + weekly water changes, most fall into that routine.
I do after the tank stabilizes. If I want to whip a tank into shape, I might do 2-3x a week water changes and stay on top of things and clean everything , even if not needed, fluff the tank's dead leaves or mulm etc, add some Excel, add more ferts than normal(since I'm doing more water changes).

You can also do what I call "mega dosing".
Basically you bomb the tank with 3-4 ppm of PO4 and 20-30ppm of NO3 the day before you do a 70-80% water change. You can do a similar thing with traces as well.

Regards,
Tom Barr