Best Dosing Methods: Planted Tank Aquariums

April 03, 2022 4 min read 0 Comments

What are the best planted tank aquarium dosing methods? The adage goes, ‘’There is more than one way to skin a cat ‘’, with the aquatic plants hobby it can equally be said, ‘’There is more than one way to dose a tank’’. This is especially true considering the myriad of parameter combinations from tank to tank.

Things like, substrate, plant choice, plant mass, livestock, co2 level and injection, lighting, local water parameters et al., all play a role in nutrient level demands in a planted tank. Some methods may be more suited to ones particular setup than others, each with their benefits and shortcomings, or specificity of use.

Most of the common aquarium plant fertilizer dosing methods have developed from each other and been adapted as new information regarding plant husbandry and care has improved over the last 30 plus years. 

Poor Man’s Dupla Drops (PMDD)

One of the first of the popular methods of aquarium fertilizer dosing for aquarium plants was created in the late 1990s by Paul Sears and Kevin Conlin, Poor Man’s Dupla Drops (PMDD). Formulated as an attempt to replicate a popular commercially available aquarium liquid fertilizer from Dupla, PMDD was in many ways an improvement, especially in the ability to adapt the mixture according to demands.

PMDD helped establish the complete nutrient dosing strategy, by methodically supplying plants with all the necessary nutrients for healthy growth. This is not to say that complete fertilization was not used before, but PMDD certainly helped solidify it as a method in the control of the hobbyists.

One significant aspect of PMDD was that the original recipe had NO phosphates added, under the assumption that fish wastes would provide enough to provide plant needs while limiting, what was erroneously assumed at the time, to be algae blooms from excess nutrient phosphates. This notion has been shown in recent years to be far overstated and misunderstood, and led to the development of EI and PPS methods. 

PMDD is a method which applies small amount doses everyday in an attempt to keep levels as stable as possible to try and stave off any potential deficiencies in interaction from any single nutrient running out. Proper dosing levels, of course are subject to the variables listed above. To try and account for this and to develop a consistent or reliable dosing level, nitrates and iron are tested over a period of weeks in repeating patterns as plant growth increases and nutrient demands shift.

This is one one of the downsides to this method, the need for constant testing. To complicate this, many Nutrient Testing kits, available reasonably to hobbyists, do not provide the consistency or detailed resolution to properly establish dosing levels.

Perpetual Preservation System (PPS)

This same issue with testing is apparent with Perpetual Preservation System (PPS) however there were some improvements over PMDD.

The PPS-Classic added Phosphates where PPMD had none. This is not to say that PPS was simply a clone of PMDD with added phosphates, because there was a lot of testing and experiments which went into PPS as well. But, ultimately, it did build upon the ground work first established by PMDD in that it was a method of daily dosing to attempt to supply what plants required without going into deficiency or excess. 

One of the plusses to PPS was that, whereas PMDD had a single base model to work from, PPS had a wider range of considerations of lighting and other variables built in so that it was even more easily adaptable to a variety of tanks, with more groundwork readily available to the hobbyist. However, similarly to PMDD, PPS required constant testing and measure early on on application to fully zero in on dosing levels. PPS-Pro became a bit more of a catchall method as opposed to Classic…in that it required less testing, and came closer to what is understood as an All-in-One style solution.

Estimative Index (EI) method

From the groundwork established by PMDD also came Estimative Index (EI) method. Refined and argued for by Tom Barr, EI Method also came from the starting point of providing a complete nutrient set for plant needs. However, unlike its predecessor, EI was not built on a principle of balancing between ‘’too much’ or ‘’too little’.

EI is based on the foundation of Liebig’s Law of the Minimum which, simply put, means that plant growth is not controlled by the total amount of nutrients available, but rather by the most limited nutrient available. Meaning that the least available nutrient will be the determining factor as to how well a plant can grow.

To overcome a system of least available or potential limitation, EI prescribes providing all necessary nutrients in amounts in excess of ‘’required’’ amounts so as to allow them to have continual access to their needs without falling into deficiency. This removes the need for constant testing and guessing. A further difference is that EI suggests a 50% weekly water change to reset values of nutrients in a tank, so that the user can be confident that no single nutrient is used up, leading to deficiency, or built up leading to imbalance. 

What is the best dosing method for your planted tank aquarium?

Of all the dosing methods, EI is by far the most accessible and easily applied for any level of expertise in the hobby. Although often thought of as only of use in High Light, Co2 Injected systems, EI can be dosed in a more lean fashion to suit less demanding tanks, while still providing a complete nutrient set. EI, above the other methods focuses on watching plant response and health rather than testing repeatedly.

Thrive All-In-One Liquid Fertilizer

Thrive All-In-One liquid nutrient dosing is based very firmly on the principles of EI dosing. It provides a complete nutrient set for multiple tank setups without having to worry about falling into any single limitation or imbalance. Thrive provides the convenience of consistent, non limiting dosing, without the need for the average hobbyist to measure dry fertilizers.

If one wishes to have a little more control over their desired dosing method, or if they have the smaller percentage of plants which may require specific dosing levels, then Nilocg dry planted tank fertilizer packages can provide all the necessary requirements for customization of any of the above described methods.