Will the filter filter out plant fertilizer?

Question

I have a filter that has activated carbon and I was planning to buy some fertilizer for my plants. I was wondering if the filter (bag + sponge) + the carbon will filter out the fertilizer. If yes, will a filter running without activated be less effective than one with carbon in it?

Answer 1

It's possible that the carbon will remove some of the iron and trace elements from the fertilizer, especially if you use a liquid type. Depending on the types of plants you have (and how they get their nutrients, from the roots or leaves), there are also pelleted fertilizers you bury at the plant roots which would be less affected by the carbon.

If you use a fertilizer (and usually only trace elements are necessary, and only at around 1/4 the suggested amount - the fish and their wastes produce most of the nitrate and phosphate needed unless you have a heavily planted tank and run CO2) you can run the tank without the carbon. I only use carbon in tanks where I need to remove medications or if there are fish or corals that may produce toxins (I keep fresh and saltwater), and it's not really necessary to use it all the time.