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Planted Aquarium Substrate Guide

This post is an abbreviated form of the 2hr aquarist article available on their website Here

Aquaticdog will soon have the full line of 2hr aquarist products available to help you create a successful planted aquarium.. stay tuned..

Click Below for another post about maximizng the potential of your planted aquarium!

What is subtrate? What does it do?

The substrate is base layer of material in a tank where plants can root and grow. It also a home for bacteria bio-film and microbes which serve as a food source for detritus feeders such as shrimp. Bacteria bio-film also binds small particulate matter together and the substrate serves as a capture point for this. In the substrate, organic debris is broken down further into nutrients that can be uptake by plants. 

Substrate can also change water parameters - for example, most aquasoils contain peat that softens the water and reduces the pH. This makes the tank environment more condusive for soft-water fish and plants. Other substrates made of carbonate minerals may raise water hardness instead - Aragonite is often used in aquariums to raise water hardness/alkalinity for Cichlids. Most plants with the except for a couple of species prefer a neutral or slightly acidic substrate

Inert Substrates

Inert substrates are composed mainly of sand, gravel, and baked clay and remain mostly unchanged over time. Most are neutral and do not change water parameters over time. They are the easiest planted substrates to manage as they have relatively low levels of nutrients and require fertilization in other forms to achieve maximum plant growth potential. Meaning less trimming and replanting is necessary to prevent overcrowding. Replanting and rescaping is easy with inert substrates, such as Seachem Flourish. Aquaticdog carries the full line of Flourish Substrates.

Many of these planted tank substrates are beneficial in that they have good porosity, and come in attractive colours & textures. Some will contain trace amounts of micro-nutrients but still require supplementation in other forms such as APT Jazz.

Seachem Flourite Review

Seachem Flourite (Above) Comes in two grain sizes and several colors. It has an attractive texture. It is also lightweight and easy to plant in.

This tank uses a nutrient rich aquasoil underneath the planted areas and an inert sand for the cosmetic feature in the center.


Aquasoils are a go-to for many aquarists these days.

Commercial Aquasoil is made from soil baked into small hard granules. This makes it much easier to manage compared to raw soil, which is easily stirred up. Many aquasoils are spiked with ammonia & other nutrients, which is great for plant growth. However, the soils do break down slowly over long time. The organic matter & porosity also provides a superior bed for bacteria colonization. The grains creates significant pore spacing which prevents compaction and overly anaerobic conditions. 

Over time the nutrient value of aquasoils will deplete, and need replenishing in the form of root tabs/additional of new soil. However, the benefits of organic matter & porosity will last a long time (years). Plants generally root better in soils than plain sand, many difficult/picky plants grow more stable in aquasoils. Having a rich substrate also means less effort need to balance water column dosing, this offers a tremendous edge in growing difficult species

Factors to take into consideration when choosing a substrate:


Grain size - Grain size of about 2mm will work well. Sizes between 1-3mm are generally usable. Avoid planted aquarium substrate sands that are superfine (such as very fine grain silica sand), which compacts more easily. Fine sand is also stirred up too easily by livestock. Pea gravel on the other hand is a bit too coarse - smaller plants with fine root systems will not root well in it.


Very light planted tank substrates are hard to plant in. This is especially so when dealing with plants that are small/delicate or with short roots. This is a small detail but cannot be ignored.


Choose sands that match your aquascaping goals. Layered aquariums often require planning ahead; a blackwater tank may look better with a mix of earth toned naturalistic mixed grain sands. A dutch style scape may choose black sand for high contrast against coloured plants. The substrate should also match the hardscape; if you have black/dark rock, white/grey sands match better than brown for example.

Seachem Flourite Black

Factors to consider when looking at Aquasoil

NUTRIENT CONTENT ​Ammonia/nutrient content/organic content - Some aquasoils are heavily spiked with ammonia (ADA aquasoil) while others are not (Dennerle). Soils heavily spiked with ammonia need frequent water changes during first couple of weeks and/or pre-cycling the tank for 1-2 weeks before planting.

BUFFERING STRENGTH Most aquasoils contain peat which reduces KH and buffers pH down. Different brands will state different buffering levels. The majority will aim to drop the pH to slightly below 7. This softwater environment is preferred by many plant species.

GRAIN HARDNESS Depending on how they are baked, and their ratio of clay to organics, some aquasoils are harder while some are softer. Hard baked soils can be more brittle. Soft soils may be easier for delicate root systems to penetrate and attach.

CONSISTENCY This refers to the size of grains, and the amount of other debris present. Some brands are more uniform than others. Small grain sizes are good for planting small delicate foreground plants such as HC or hydropiper. Coarse grains compact less easily over time. Aquasoils with more differentiated grain sizing may look more natural.

Ultimately no matter how rich in nutrients a substrate is, it is no substitute for proper water column dosing when optimizing plant growth.

We have been getting great results with the APT 3 Complete fertilizer, even our fittonia (nerve plants) growing out the back of the aquariums have been lush and pink!

Click Here to read the 2hr aquarist article on creating slopes with your planted aquarium substrate!



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