Does sand collect nutrients?

[lectraplayer]

I'm new to sand and am starting a planted tank. I put the sand in with soil underneath. I keep noticing dark spots in the sand as I do my cleaning the top quarter inch with this soil being two inches down. I know everything sinks, but are these dark spots a collection of nutrients? Will the sand collect nutrients like this rapidly enough for the plants? 29g lit with dual 40's...

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[BBradbury]

Sand and Nutrients

I'm new to sand and am starting a planted tank. I put the sand in with soil underneath. I keep noticing dark spots in the sand as I do my cleaning the top quarter inch with this soil being two inches down. I know everything sinks, but are these dark spots a collection of nutrients? Will the sand collect nutrients like this rapidly enough for the plants? 29g lit with dual 40's...

Sent from my ALCATEL ONE TOUCH Fierce using Tapatalk

Hello lec...

The bottom material doesn't collect nutrients. The decaying plant and fish material will settle to the bottom and eventually dissolve. The nutrients are in the tank water.

B