Capping Dirt (Sand or Gravel?) Poll

[Rich Guano]

OK my friends. It's time to weigh in on whether Sand or Gravel is a better top cap to MGOC Potting Mix.

I like the look of Sand, with a handful of gravel strung across its surface. And sand is an excellent top cap, maybe to good. Does sand prevent organics and nutrients from returning back down into the soil? Can this be overcome by the addition of snails and worms? (which i already use)

I am thinking long term here. I am in the process of converting over all my tanks to dirt. I am already convinced on the benefits of nutrient rich dirt, I am just trying to get the longest possible run on any given installation of dirt. (I don't want to re-scape the tanks "ever" if possible).

What are your thoughts? Any pros/cons I have yet to ponder?

[mitchfish9]

I also was thinking that sand would not let the fish waste down to the dirt and the roots, but I am convinced that if you have a fish like cories(probably even without them) that the waste is eventually broken down enough and makes it down to the dirt to use. Because the nutrients will become smaller even than grains of sand. I would use malaysian trumpet snails, even though some people get overrun with them. Just try not to over feed. If you do gravel it should be a fine pea gravel. My gravel is too big and I believe it is having a negative effect on the water quality.

[wkndracer]

At this point can't really say which I think would last longer because none have failed to date here. The oldest dirt tank started with slightly over 1" of MGOCPM covered with what is now more than 1" of flourite original. More cap was added after the organics collapsed to maintain depth for a rooting base. That one was started in 1999 and still grows thick crypt beds without additions or changes except random doses of trace after water changes so 4yrs wet in April.

Mixes of sand and flourite original, flouite, PFS, Eco-Complete, EC and black coal slag and coal slag alone here but all are doing about the same. Different light intensity and CO2 injection might make a difference but not sure on the cap really being a factor. (not voting)

[dusted]

I'm not sure if this is a common issue capping with sand but when I did it my amazon swords root system started to rot. This all happened about 4-6 months after setting it up and then all my root feeding plants started to melt. I got pissed and went out and picked up a 50lb bag of pea gravel from menards and the tank is doing great now.

It could be to much of a sand cap but it was 1 inch of dirt mixed with small clay chunks and 1 inch of sand cap.

[SouthernGorilla]

I didn't vote for either. I've become convinced we aquarists spend too much time debating "either or" and ignoring the middle ground. Why not make the cap a mix of sizes? Sand, aquarium gravel, even a bit of river stone mixed in. That way you get a variety of textures for visual appeal and the various sizes will create tunnels for nutrients. Whichever you choose I definitely second the recommendation for trumpet snails.

For what it's worth, I'm seriously considering experimenting with using a leaf bed as a cap on my next tank.

[wkndracer]

came back to the thread and voted sand LOL

[darthmilmo]

I voted sand. I usually do 2 inches of dirt (shrinks/compacts over time) and 1 inch of sand. I have tried more than 1 inch of sand, but it actually makes it hard for the plants to reach the dirt, so 1 inch will do.

The problem with gravel is that it makes it a nightmare for foreground plants like HC, dwarf-grass, glosso, etc. It's harder for these plants to put a foothold. Nevertheless, gravel does serve it's purpose if all you want is bigger stem/root plants.