aquabillpers;31600 said:
Why don't aquariums overdosed with nutrients via EI develop algae? I don't know. Maybe the amount of excess nutrients has to reach a critical mass before the algae can get a foothold, and the EI approach, with water changes, doesn't let it get to that point. I wonder what would happen, algae-wise, if the dosing continued without water changes?
I do note that some of the posts here and at other places by people who use EI are about algae problems.
Vaughn, what can I do to convince you that in some cases excess nutrients do cause algae? With what in this post do you disagree?
Bill
I'll take Bill's side and play devil's advocate for a bit here.
Some examples gleened from the research are some Danish lake studies and Florida lake studies(Both shallow with and without plants).
In each case, it is where there is a relatively low % of sediment coverage where algae dominated. So, if you have about 20-30% of the lake's area infested with aquatic weeds, then it typically will have low algae if the system is stable(no hurricanes, draining, sewer inputs etc).
Here are two good comparative papers:
In Florida:
http://fishweb.ifas.ufl.edu/Faculty Pubs/CanfieldPubs/macrophyte.pdf
And in Demark:
SpringerLink - Journal Article
Note where they suggest top down control is more imprtant EXCEPT where submersed macrophytes are present.
So it is the plants that define the systems, where present, not the nutrients.
This is the focus many aquarist try to tell many new folks or those having issues, focus on the plants, not the algae. Do not orry about the nutrients being "too high".
With non CO2, things take longer, but like any planted tank, a stable tank and good adaptation will account for successes.
I think we also need to be specific, which nutrients? We cannot say "all nutrients" or just nutrients in general. That does not tell us much or what we need to know.
As far as no water changes and EI, you start to get salt stress in plants and dead fish/shrimp. Same for Hydroponic solutions that keep evaporating too much without water addition and replentisment/change out.
As far as EI and algae, there is no single dosing method that avoids algae, there will always be folks that get algae using each and every method.
This is due to factors other than nutrients cause algae, this is the old tunnel vision with nutrient issue.
Lookat good meaure for light, look at good measure for CO2, or provide good stable CO2 conditions and the time to adapt.
CO2 wrecks havoc in every dosing method.
I'd say to the point it causes more algae, more fish death etc than anything else.
So why the fixation with nutients and not CO2? What drives CO2 demand in plants? Light, so why add more light and assume it is better?
These are not new concepts and new information. Yet folks wander off time and time again. I've been a nag about this well over a decade ago and still today.
This has not changed.
More evidence for it has however.
As long as there are enough nutrients for a given rate of growth for plants, things should be fine with any dosing method. Changing light and/or CO2 changes that and folks need to adjust the CO2 and nutrients to account for it.
Most do not.
Then have issues, mild medium or serious depending on how far off they are
Non CO2 methods are nice since they start with low light, easy dosing, no CO2 issues and hopefully lots of plants and few floating leaves, algae eaters etc.
So that takes out about 80% of the issues many have staring out with. But the rates of growth are slower, some like it, some love the CO2 gas and pearling like mad and seeing the plant growth day to day.
So there are some trade offs.
Still, algae issues will hapen in every method because of human assumptions ans failures, not the method itself, each can and should work well, you might not like the trade offs, (WC's, Testing, lower light, more CO2 etc etc), but you reall shoukd work with the assumption that they can and do work.
Once you prove that to yourself, then you get a better idea about algae, nutrients and how they interelate. Clearly each method works within some parameters.......just accept that it it does, just not for you.........at least for now...because you keep failing at it. Hopefully you learn from those failures.......that's how we learn, we make mistakes and try different things.
So that is part of the process, not evidence that a method does not work.
We already know and acept the assmption that it does faced with many observations.
I've never stated PPS does not work nor sediment based ferts.
I have stated trade offs, and why they work, and also that the underlying notion that excss nutrients in the water column are not a risk as proponents of either/both methods have both claimed.
I base my argument on logic, basic common sense, evidence and observation. Not belief, poor testing methods and poor assumption. Neither PPS or sediment folks have meaured the light or CO2 critically.
We use only sediment ferts at the lab and measure light, depth, O2, pH, EC etc, they get nasty algae rather fast in every case even with flow through continuous water exchange. But the light is pretty high also, but not that high compared to planted tanks, we shoot for about 200 micromol.
Regards,
Tom Barr