Seachem Flourite Substrate

[jefft]

Does this stuff need to be replaced after a certain time period? I've had it in my tank for a little over 3 1/2 years and my plants are doing worse and worse over time, and I'm wondering if the minerals and iron have been reduced over the years due to cleanings, etc? I never did have much light (1 watt/gallon) so I finally upgraded to over 3 watts/gallon thinking that would do the trick, but it did nothing for the plants. I do weekly water changes and use fertilizer as well.

Any advise/help would be appreciated.

Thanks.

 

[Lateral Line]

If you've not got enough light - no amount of CO2 of fertilizers are going to help. Bear in mind that 3 Watts/gallon is marginal for some high light plants like Cabomba sp., but should be adequate for most.

Once the light is right, CO2 becomes the next limiting factor. The light enables the plants to photosynthesize CO2 into sugars/starches which can then be used to build more plant. If there is enough light, but not enough CO2, this cannot happen. No ammount of fertilizer will help.

Once you have enough light and enough CO2, there are some other nutrients required for metabolism and further synthesis, nitrates, phosphates, iron etc. It is not uncommon for the bio load, (fish/bacteria), in the tank to provide just about all of that apart from a few trace elements, which is where your fertilizers come in, i.e. right at the end - if needed.