You won't want to add a cap after plants have gotten established- you'll just bury them and it might even rot stems.
You do have lots of good options, though- any of those will work, so it really boils down to the positives and negatives of each one (all substrates have positives and negatives) and which you like best.
Personally I'm not a big fan of layering since layers almost always end up getting mixed over time anyways. Only time I layer in my tanks is when there's a very lightweight substrate that really does need to be "held down" with a cap, like Mineralized Topsoil or Miracle Gro. Otherwise, I go ahead and just mix everything all together from the getgo, so you get a more uniform appearance in the tank.
I understand. My purpose for capping with Flourite Black or Black Sand "after" the plants have had time to get established is primarly for appearance sake, wanting that look. I realize overtime, layers will get mixed up, with the finer materials settling and the courser materials surfacing. Also the finest of particles end up in the water column, hopefully in some short time, either settling out, doing so faster without water flow which tend to keep them in a suspended state, or removed with mechanical filtration with water flow. If, or more accurately "when", the Flourite ends up in the layered mix, great, or so what, it is an acceptable to great substrate by itself.
Capping, in this case, is a way to stretch the dollars spent on subtrate.
Not having a master plan, the substrate could end up having little surface exposure or none at all. Meaning natural rocks, natural driftwood and live plants, including maybe carpet plants might cover most if not all of the substrate. What the substate looks like than, doesn't matter if it is covered by something. Capping would not hinder established plants, only applying it to bare and exposed substrate, between natural decorations and between plants.
Originally Posted by Seattle_Aquarist
Hi Jeff (Dacotah7),
I use both Soilmaster Select (SMS) Charcoal and Turface Pro League Grey and can tell you that they are basically identical in weight, color, grain size, and their effect on water chemistery. My plants grow like crazy with either substrate. The weight is about the same or a little heavier than ADA Aquasoil. A 50# bag covers six square feet (6 sq ft) to a depth of about 3.0" and costs about $20 at our local John Deere Landscape location. I have been told by individuals that have used both the Soilmaster Select Charcoal and the Aquariumplants.com Black Diamond, that they are very similar.
Soilmaster Select (SMS) Charcoal in 30 Gallon
Unfortunately SMS is no longer available and Turface has discontinued the "Grey" color in the "Pro League" product line. As a result, I will probably try the Turface Pro League Heritage Red
color when I need to buy a new bag.
That sounds great. Well, except the discontinued products and the resulting search for available equivilents.
The John Deere Landscapes' salesman, got all wrapped up with the aquatic aspect. I told him, forget that I will be growing plants submerged. For the sake of this converstation plants are plants. They all need macro (NPK) and micro nutrients, (iron & minerals) and of course light, water, O2 & CO2. He got hung up with, or was focused on my "wet" plants, while my questions related to his dry "dirt". LOL! ...a bit of a communication disconnect.
Further compounded by their companies' focus is on sports applications and the problems it eliminates or solves on the sports playing fields, with little or no data on the material composition, or its suitabilty for plant growth. A well groomed baseball field has no plants where many of their products were designed for.
I really don't need the data sheet of the chemical composition. What I need I am finding on this forum and in this thread from others with experience:
- It grows plants like crazy, (with proof in the photos)...
- The pros and cons of the material - particle size and weight...
- Works great, no longer available; But this other product is a suitable replacement with the same characteristics... etc.
$20 for 50lbs, covering 6 sf at a 3" depth is most desireable. My tank is 9 sq ft (1.5' x 6'). Two bags, or one bag plus some other inexpensive yet desireable material, should provide enough depth. Anything leftover can go in the vegetable, herb or flower garden.