Does using activated carbon reduce or eliminate the need for water changes?
No, water changes still remain an essential part of maintenance.
Are all carbons designed for aquarium use ?

No, usually quite the opposite. Most carbons are destined to be used in the chemical industry and air purifiers. Many are treated with phosphoric acid, which carbons for phosphates by introducing a few fresh 10 minutes, test the water with a phosphate test kit. Those carbons revealing no phosphates are to be recommended.
Can a good Quality activated carbon help restore flagging sessile invertebrates?
Yes in many cases, especially with a 33% high quality water change.
Does the use of carbon eliminate the need for a protein skimmer?
No. Skimmers and carbon remove different pollutants and one can only complement the other.
You have just read another great aquarium blog post by iQuatics. If you would like us to blog about a specific subject or have your own aquarium blog content you would like published on our website, get in touch. Together we can help grow the iQuatics aquarium blog into a vast resource full of combined industry knowledge.