Many hobbyist just entering the hobby will have “sticker shock” when they see the prices for good quality live rock. Sometimes this will result in just trying to find the cheapest approach to filtration. This is the wrong approach to take. Cutting corners on your filtration will always result in long term difficulties. Let me explain…
You have a few different options when it comes to providing proper filtration for your marine aquarium. Here are the common approaches to filtration in marine aquariums as well as the pros and cons. Before reviewing these, you have to also consider the three categories of filtration that you need address – biological, chemical and mechanical. Each has a slightly different purpose in your aquarium.
The term biological filtration refers to the process of lie bacteria converting organic waste in the form of ammonia and converting it into nitrates and further converting that into nitrates. This is also referred to as the nitrogen cycle. The two most common approaches to biological filtration are to use either live rock or a filter with biological filter media (like you would find in a fresh water aquarium).
I have always had the best results using live rock for biological filtration. Times that I had tried using a canister filter with biological filter media, I struggled to obtain close to the same results as the live rock would always provide me. However, I have very high personal standards when it comes to the water quality in my marine aquarium so to each their own.
Chemical filtration in a marine aquarium refers to using a filtering media which absorbs certain unwanted elements or certain pollutants out of the water. One of the more commonly used chemical filter media is the use of carbon to remove toxins from the water when or if some of your corals release toxins as a defense mechanisms into the water which can harm the rest of the marine life in your tank. Other popular chemical medias include phosphate removers like Rowa Phos and carbon based media like Chemi-pure. You can use chemical filtration in a filter, a media reactor or passively in a sump provided the flow is correct for the media being used. Just remember to check the manufacture’s recommendations for proper use and follow those instructions.
I always prefer to have at least some chemical media in my set-ups as a precautionary measure in case any toxins are released into my aquarium. That is why I will use a carbon based media passively in the first compartment of my sump. In the past, I also used phosphate removing media in a media reactor so I could control the flow to match the manufacturer’s recommendations. Although I have not used any phosphate removers in a long time, I always have carbon based media in my marine set-ups.
There are a few different ways this is achieved. Among the more common ways is to use a filter pre-sponge on a filter or skimmer intake, using filter socks on a drain line or in a sump, or using sponges between two sections of a sump. Some people do not even use any mechanical filter media in their marine aquariums at all. As I have sumps on my marine tanks, I choose to use filter socks for mechanical filtration. I prefer a 100 or 200 micron filter sock which seems to be fine enough to catch and filter out most partials from the water while not becoming clogged to fast. Many people will use 200 and 300 micron filter socks to filter out all partials from their water, but I have found the finer material will clog up too quickly. Mechanical filter media does require frequent cleaning in order to prevent nitrates from being produced and placed into the water. The exact frequency of the required cleaning will depend upon your set-ups as this can vary greatly between different aquariums.
Nitrate and Phosphate Removal
This is the one area that hobbyist can spend the most effort on. Higher levels of nitrates and phosphates can lead to problems such as nuisance algae growth or even stressing your fish and corals if the levels get high enough. This can be done in a few different ways – live rock, algae scrubbers, macro algae, carbon dosing, water changes, deep sand beds and refugiums.
As with most aspects to filtration, more is usually better. That is why I will always use a combination of a few different ways to remove nitrates and phosphates from my water.
They remove organic waste / proteins (solid and otherwise) from the water before these substances have a chance to break down and eventually result in nitrates. As a skimmer does this mechanically, it will not nicely fit into one of the above mentioned categories. That is why I did not mention a skimmer under any of the above headings as it can be included in more than one category. This is only one of the many reasons that I will always have a skimmer on my marine aquariums. I like to have a skimmer that is rated for a higher water volume as compared to the set-up I am placing it on.
By following these multiple approaches to proper filtration in your marine tank, your water parameters for ammonia, nitrites, nitrates and phosphates should all remain undetectable by test kits. Overall, it’s recommended to hire a knowledgeable aquarium service company if you are new to the hobby, lacking knowledge on proper tank maintenance or just don’t have the time to dedicate to your marine tank. Not properly caring for your aquarium will result in costing you more money in the end, which is why good service and maintenance is a must.
Information shared by Reef Aquarium: Your Guide To A Thriving Reef