I have found a guy who is willing to sell 43 lbs of Eco Complete Substrate for $10. He said it has been used for 6 months. He claimed it never goes bad. Is this right?
In a sense. There's two things to look at here - the initial nutrient content of the substrate, and it's CEC (cation exchange capacity).
The nutrient content will eventually run out, so in that manner, it can "go bad". How fast it depletes depends on a variety of factors - how many plants you have, how fast they're growing, etc.
The other thing is the CEC - this determines how well the substrate can capture and hold nutrients from the water and transfer them to plants. Eco-Complete and other specialized plant substrates have a higher CEC than regular gravel, so even after their initial nutrients run out, they're still more useful than gravel for this reason. CEC doesn't "go bad".
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In a sense. There's two things to look at here - the initial nutrient content of the substrate, and it's CEC (cation exchange capacity).
The nutrient content will eventually run out, so in that manner, it can "go bad". How fast it depletes depends on a variety of factors - how many plants you have, how fast they're growing, etc.
The other thing is the CEC - this determines how well the substrate can capture and hold nutrients from the water and transfer them to plants. Eco-Complete and other specialized plant substrates have a higher CEC than regular gravel, so even after their initial nutrients run out, they're still more useful than gravel for this reason. CEC doesn't "go bad".