Differentiating between nutrient deficiencies and problems caused by fluctuating nutrient levels.

[Sb1415]

Actually, it's entirely the opposite, the APT3 tanks run much more stable than the EI approach. Over the years, our customer base has self moderated over time, and APT3 outsells our APTe almost 10 to 1. [When we first started the ratio was 1:1, but most customers did not manage to make the Ei system work].

Thanks Dennis this makes so much sense. I think the plant adaptation part and the slow speed of change seems like the key for the lean dosing system.

 

[Dennis Wong]

Thanks Dennis this makes so much sense. I think the plant adaptation part and the slow speed of change seems like the key for the lean dosing system.

Not only that, but lean water + rich substrate can really grow almost any plant (include pretty "difficult" stuff such as sp chai or Red Erios) as easily as rich water column tanks, but with less catastrophic outcomes if algae spike occurs. Growth speed is traded off for all-round stability.

Entire chai patch was grown from 2 stems. Tank was run in zero-bound approach, nitrates in water column never rising above 5ppm.


Same approach as above, but with Pantanal instead - aged aquasoil, but enriched with root tabs:


In new tanks, when the soil is fresh, and the tank isn't over crowded by older growth, the lean water, rich substrate method provides an easy route to success. Most of its difficulty comes in the long term - what to do when aquasoil depletes, and how to handle plants that are heavily dependent on substrate feeding when the rootzone gets compacted etc. For folks that start with high water column nutrients, the difficulty is upfront - failure at balancing nutrient levels or managing tank maturity leads to much heavier algae spikes in new setups. This approach is very penalizing to newbies.

Imagine managing this tank as a less experienced aquarist :

Would you believe if your "expert" friend tells you that if you focus on plant growth it'll pass ? Or will the newbie likely panic and do something else drastic? This algae outcome is rare for tanks that start out with lean water column, rich substrate. Its easy to hit if you start with high water column nutrients, and haven't done enough steps to prevent it from happening/spreading.

On one hand, it is absolutely true that a tank with high water column nutrients, but with high plant mass, plant dominance, can be stable and algae free and with good horticulture technique, be algae free in quite a stable way.

On the other hand, most aquarists are inconsistent in some way due to either limitations of time, equipment, experience, or knowledge. Algae spikes do happen, and their runaway effects are much much more severe in high water column nutrient tanks. The average aquarist out there would be okay living with imperfect growth, and controllable, small amounts of small algae - but many of them cannot deal with more severe algae spikes. This is highlighted by Josh sim's interview. Even for someone thoroughly vested in the aquascaping game, he chooses the lean water, extremely "conservative" nutrient dosing approach for the same reasons [and every commercial shop out there operates this way as well].

I think folks here have loftier goals than just growing easy plants painted on pretty hardscape. However, if any of you guys have been juggling high water column nutrients for a long time without producing picture perfect plants. Maybe it is a good time to see if the slower, but more stable method might produce easier outcomes.

 

[Sb1415]

Not only that, but lean water + rich substrate can really grow almost any plant (include pretty "difficult" stuff such as sp chai or Red Erios) as easily as rich water column tanks, but with less catastrophic outcomes if algae spike occurs. Growth speed is traded off for all-round stability.

This really ties it all together!

After reading the part on accumulation and the real world rates "In this above example, accumulative nitrate levels keep below 5ppm consistently with some room for error. This is an example of a system where there is slight excess, but nitrates availability never rise enough for plant-reprogramming to occur." Is targeting < 5 ppm a good thumb rule for lean dosing as long as plant growth is good without algae ?

Thanks Dennis for clarifying many concepts on this nuanced subject! much appreciated.

 

[Dennis Wong]

This really ties it all together!

After reading the part on accumulation and the real world rates "In this above example, accumulative nitrate levels keep below 5ppm consistently with some room for error. This is an example of a system where there is slight excess, but nitrates availability never rise enough for plant-reprogramming to occur." Is targeting < 5 ppm a good thumb rule for lean dosing as long as plant growth is good without algae ?

Thanks Dennis for clarifying many concepts on this nuanced subject! much appreciated.

It depends on the current state of the tank. Lets say we have a typical nature style tank (like below) where say the normal uptake rate is 2ppm NO3 per day. I could dose 2ppm NO3 a day and get 0ppm residual NO3, or I could dose 0.5ppm NO3 a day and also get 0ppm residual NO3. However, the second tank will be in deeper deficit so to say. Aquariums that are grown in deep deficits over a sustained period start to get plants into a starved state - growth/metabolism slows and plants get delicate. Many ADA style systems get into this state long term. For such aquariums, even small nutrient spikes can trigger algae blanket across the plants - even though the plants may eventually adapt and grow better/stronger, the sudden availability of nutrients will cause an algae spike. In such a scenario you need don't to exceed 5ppm NO3 in this scenario to get an algae spike. I've seen this happen with many of 2hr Aquarist's customers that switched from ADA dosing system to APT3. It is funny, because depending on who you ask, APT3 might seem to be a "lean dosing" method [that kinda aims to be zero-bound stable for many tanks], but its rich enough to trigger said reaction from the switch from ADA dosing.

In most tanks where dosing is not too far off from the zero-bound (meaning that there is some residual in the water column), there is far greater flexibility. I think 5ppm is a very conservative level. If your plant selection is easy, one might not see much reaction from most plants till 10-15ppm + NO3 spike from zero bound.



I find it interesting that even in forums with relatively experienced folks whenever Green spot algae is seen, the default advice is "INCREASE YOUR PHOSPHATES !". GSA on older leaves is one of the most common symptoms of a short term nutrient spike. Depending on whether you meant to upshift nutrient levels to a more elevated state or not - this might be an expected outcome that needs no further action except to replant new growth, clip old growth. If one did not intend to shift up nutrient levels, then the corrective action is in fact the opposite - to do large water change to reset levels to the lower equilibrium point. Old leaves still need to be clip - the damage that is done doesn't heal, but the plant could well grow normally, algae free there after.

This is why diagnosing algae issues is much more complicated than looking at single picture. Depending on the history of how the tank got into the state matters a lot.

 

[Pepere]

that kinda aims to be zero-bound stable for many tanks

Dennis could you explain the term “zero-bound stable;” or direct to a page that discusses it in detail?

 

[Dennis Wong]

Dennis could you explain the term “zero-bound stable;” or direct to a page that discusses it in detail?

Its in the article link in the first post

 

[Sb1415]

I find it interesting that even in forums with relatively experienced folks whenever Green spot algae is seen, the default advice is "INCREASE YOUR PHOSPHATES !". GSA on older leaves is one of the most common symptoms of a short term nutrient spike. Depending on whether you meant to upshift nutrient levels to a more elevated state or not - this might be an expected outcome that needs no further action except to replant new growth, clip old growth. If one did not intend to shift up nutrient levels, then the corrective action is in fact the opposite - to do large water change to reset levels to the lower equilibrium point. Old leaves still need to be clip - the damage that is done doesn't heal, but the plant could well grow normally, algae free there after.

Thanks again! This has been my confusion for a while and glad for it to being clarified. It is good to know that I can agree with both "phosphates don't cause algae" and "phosphates can cause algae" !! nuanced topic indeed!

I've seen this happen with many of 2hr Aquarist's customers that switched from ADA dosing system to APT3. It is funny, because depending on who you ask, APT3 might seem to be a "lean dosing" method [that kinda aims to be zero-bound stable for many tanks], but its rich enough to trigger said reaction from the switch from ADA dosing.

In this same line as before, do you think it is because the ADA system does not have phosphates while the APT 3 does ? Was the rationale to add phosphates because of the same long time growth issue seen with the ADA system ? I have read and even heard Tom Barr mention that phosphates tend to bind in the aquasoil and while nitrates often deplete others accumulate in aquasoil. Could you speak about this as well. Thank you!

 

[Dennis Wong]

Thanks again! This has been my confusion for a while and glad for it to being clarified. It is good to know that I can agree with both "phosphates don't cause algae" and "phosphates can cause algae" !! nuanced topic indeed!


In this same line as before, do you think it is because the ADA system does not have phosphates while the APT 3 does ? Was the rationale to add phosphates because of the same long time growth issue seen with the ADA system ? I have read and even heard Tom Barr mention that phosphates tend to bind in the aquasoil and while nitrates often deplete others accumulate in aquasoil. Could you speak about this as well. Thank you!

I think ADA is just anachronistic in its approach, borrowing back from the days that phosphates was the main blame for algae - their systems are phosphates limiting by design. For folks with good access to well run ADA shops/systems, its worth studying those systems to get some insight as to what really happens when a system is PO4 limited long term (does GSA always occur? heh). APT3 adds more PO4 because it aims to be N limiting - by design, N has to be lower. However, there are many other considerations when designing a commercial fertilizer - impact to average users vs impact to the 1% that makes for good marketing, time to see results, long term accumulation etc.

The main thing that depletes in aquasoil substrates long term is nitrogen content. Most folks dose quite a bit of excess K, so aged aquasoils tend to have a lot more K than fresh aquasoils. I think whether PO4 accumulates or not depends on the dosing approach

 

[Noahspapa]

Question - what is considered a desirable phosphate level as measured by API test kit? I am using only APT3 dosed daily via Sentia doses. No extra ferts. I believe another way to see spike in phosphates is over feeding?

 

[Noahspapa]

These are my water test results across my tanks. I have been “dialing in” my co2 after switching to horizontal reactors. I believe I was basically starving them so to speak.

 

[Naturescapes_Rocco]

I have had the best success with 6-9ppm PO4 in the water column. This is for high energy tanks with lots of macros in the water column.

Basically, anything other than 0-1ppm, or my tanks instantly get stunted growth and algae.

I've been aiming to at 0.3ppm PO4 for every 1ppm NO3.

This is with large (70%WC) each week.