How to use Play Sand as a Substrate?

I intend on using play sand as a substrate in my planted tank because I want the best habitat for my corydoras. What I'd like to know is how do I grow plants like amazon swords, sagittaria platyphylla, Vallisneria spiralis and Myriophyllum mattogrossense which I understand are for the most part heavy root feeders, when Play Sand has no nutrients in it. Root tabs are great but placing root tabs under plants like sagittaria platyphylla which spread and carpet seems like a daunting task and an expensive one as I'd need a lot of root tabs. Any advice on using play sand in general would also be appreciated.

Have you thought of dirting the tank? This is when you add a layer of dirt to the bottom of the tank, then a layer of sand which keeps the dirt out of the water column. The plants feed off the nutrients in the dirt and you shouldn't ever have to use root tabs or, depending on the lighting, liquid fertilizers either.

These are my dirted tanks, I don't dose liquid fertilizers in the 10gal, but I do for the 29gal (work in progress).

Demeter32 said:

Have you thought of dirting the tank? This is when you add a layer of dirt to the bottom of the tank, then a layer of sand which keeps the dirt out of the water column. The plants feed off the nutrients in the dirt and you shouldn't ever have to use root tabs or, depending on the lighting, liquid fertilizers either.

These are my dirted tanks, I don't dose liquid fertilizers in the 10gal, but I do for the 29gal (work in progress).

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Would ADA aqua soil with sand on top work?

I do not recommend dirt for two reasons. First, the "nutrients" in it are limited, and likely not all present anyway, and the dirt will be completely exhausted of any nutrients within a year, at which time it will be comparable to play sand after a year as far as nutrients go. And second, there are some serious detrimental issues with dirt during the first six months, primarily increased ammonia (this can be lethal to fish) and nitrates. Many dirt-substrate authors suggest a dry start for six months to avoid the latter problems, but you still have the former. The only real benefit of dirt is the high level of CO2 immediately. In a new tank, it takes a few months for the detritus to establish in the substrate, and the breakdown of organics (detritus) by bacteria in the substrate is the primary source of CO2 for plants. Obviously there will be CO2 from other sources, like the water itself (tap water often has lots of CO2), and respiration of fish, plants and some bacteria species.

As I was typing, post #3 occurred. I tried one of these so-called enriched substrates in one tank, but it did nothing I could see for the plants. You really do not need this anyway, as I will explain.

Aquatic plants take up all their nutrients from the water, via roots and leaves. The nutrients in the substrate must dissolve into the water in order to be taken up by the roots of the plants (this is the same in terrestrial plants). So this means you can use simpler methods to get the nutrients into the water, and the normal circulation of water through the substrate will allow the plants to extract the nutrients. The nutrients taken up primarily by leaves will come from the upper water obviously. So a comprehensive liquid fertilizer will provide this.

Substrate tabs are good for large plants like swords; I use these for my large swords (Echinodorus sp., not the pygmy chain swords which technically are in the genus Helanthium), Aponogeton, and red tiger lotus. I find this simpler than dosing excess liquid fertilizers which can cause algae issues, plus they get into the fish more; substrate tabs like Seachem's Flourish Tabs do not have either problem because they only release nutrients as the plants need them.

I have play sand in all my tanks now; previously I had fine gravel (except the one with Flourite that was a failure).

The plants you mentioned in post #1 will thrive in play sand. The only one I have not myself cultivated is Myriophyllum mattogrossense which is a stem plant and thus liquid fertilizers in the water will benefit this plant more anyway, as is the case with most stem plants.

Byron.

Thanks for the well detailed reply. Helps a lot thanks