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Saltwater Aquarium Filtration - Mechanical Filtration

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Last updated on November 23rd, 2023


Saltwater Aquarium Filtration - Mechanical Filtration

What is Mechanical Filtration for Saltwater Aquariums

Mechanical filtration is the use of saltwater aquarium filter media to remove debris from the water before it can break down into nitrate and phosphate. Some common examples are filter socks, filter floss, protein skimmers, or any other aquarium filters and aquarium filter media that remove debris from the water before it can break down.

Reef aquarium mechanical filtration is the first line of defense between nutrients and your aquarium. Mechanical filters are one of the most basic and fundamental concepts in maintaining a reef tank. When you feed fish, there is food that does not get eaten. The food that does get eaten will eventually be converted to waste (yup, we're talking fish poop). Both of these will eventually break down, or rot, and increase the nitrates and phosphates in your reef tank. If left uncontrolled, this will lead to poor water quality, illness, algae, cyano, and possibly death in your tank.

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Mechanical aquarium filters remove waste before it breaks down and causes parameter swings in your tank. Though there are other layers of filtration such as biological and chemical filtration that can help remove the nutrients after they are in the tank, mechanical aquarium filters will remove the waste before it becomes a problem and help reduce the dependency of other saltwater aquarium filters. When thinking about mechanical filtration, think of it as "An ounce of prevention is worth a pound of cure". By preventing the nutrients from even entering your aquarium, you won't have as large of problems that need to be fixed.

Types of Saltwater Aquarium Mechanical Filtration

Filter Socks

Filter socks are one of the simplest forms of mechanical aquarium filtration available for reef tanks. Filter socks are placed in the sump, usually over the overflow drain pipe. Any waste that goes through the overflow will get caught in the filter sock and will be removed by changing the filter sock. There are a variety of sizes of filter socks, but picking the best one for your aquarium is simpler than you'd think. Filter socks have a variety of pore sizes, but for the most part, 200 micron filter socks will handle most of the waste in the water without clogging too fast. For finer filtration, 100 micron filter sock and even smaller options are available if needed. Beyond this, choose the width and length of filter sock that best fits your sump.

For filter socks to remove waste before it breaks down, the socks need to be replaced roughly every other day, or better yet, daily if you can. That said, you can probably get away with replacing filter socks a little less frequently, every day you wait is more waste broken down and added back to the tank. Changing these socks takes minutes at most and the only reason not to do so is not having enough filter socks on hand. However, at the low cost of this reef aquarium mechanical filtration method, there is little reason not to purchase at least 8 to 10 of them to have on hand.

Cleaning Filter Socks

Some people throw away filter socks after one use, this gets very expensive because if you were to replace the filter socks every other day, you will spend nearly $1,000 USD per year. This is a lot when all you really need to spend is $50 - $60 per year if you just wash your filter socks.

To wash the filter socks, simply turn them inside out, rinse out any debris in the utility sink, and toss them in the washing machine. You can use a small amount of bleach to remove the coloration and smell. Make sure you wash the filter socks in hot water. After the wash is done, I like to do one more hot water wash, though most agree it only needs an extra rinse cycle. Then simply let the filter socks air dry and they're ready for use again! A word of caution though, DO NOT wash filter socks with any detergent or other chemicals, and do not wash them with anything else. No clothes, towels, rags, anything. You do not want any gross fish and coral poop/toxins to mix with the other laundry or chemicals to mix with the filter socks, etc.

DIY Aquarium Filter Socks

You can make your own filter socks using felt from most fabric supply stores. There are a variety of templates and how to articles online that will help you make your own filter socks. This can save you even more money and further reduce the cost of successful reef keeping. If you are like me, and do not know how to sew or simply don't trust the quality of do it yourself filter socks, you can order these filter socks as a simple, cheap solution.

Automatic Filter Roller

Filter socks are the simplest, cheapest solution to reef aquarium mechanical filtration. The downside is that you need to change the filter socks every day or two for them to work the best. Most of us don't want to change filters daily, even though it only takes minutes. That's where the automatic filter roller comes in to save the day.

Automatic filter rollers have all of the benefits of filter socks for reef tanks, with the added benefit of not needing daily maintenance. The automatic filter roller will roll up the debris filled pad as it gets clogged and then you simply need to replace the roll as it gets used up. This filter has a higher cost up front, but the replacement filter pad rolls are fairly cheap. So if regular maintenance and time are concerns of yours, check out the Automatic Filter Roller to save yourself some time with daily maintenance.

Protein Skimmers

Protein Skimmers are a cone shaped filter that has tank water flow through it and a large amount of microbubbles pumped into the cone, mixing with the tank water. The microbubbles cause waste to rise to the top of the cone and remove it before it can break down.

An additional benefit of the protein skimmer is that it helps force oxygen into the water. The microbubbles used for removing the waste will provide oxygen that may have been depleted by the fish, coral, or other organisms. Providing oxygen to the aquarium helps to stabilize the pH of the reef tank. This is why protein skimmers are the most popular filter for saltwater aquariums. Though it is possible to run a saltwater aquarium without a protein skimmer, it's more difficult and there are not many, benefits of doing so.

There are both AC pump and DC controllable pump varieties for protein skimmers available. The DC pump options are much more advance and allow you to control both air and/or water input for tuning of waste collection. Dc Pumps are also much quieter than the AC Pump options Though DC Protein Skimmers are typically a better option, they are often much more expensive. For the majority of us, the AC pump protein skimmers work perfectly fine, but if you have the ability or need, the DC pumps are much nicer.

Canister Filter

Canister filters are a very common aquarium filter in the freshwater aquarium hobby, but not as common for saltwater aquariums. This is because there are other options to provide the same filtration that is easier to maintain. Most canister filters have a sponge or filter-floss layer, an activated carbon layer, and maybe an area for biological filtration. The reason the canister filter is less popular is because most reef tanks have sumps, meaning you have better options for these filtration media.

The filter floss and sponge layer is replaced with filter socks or rollers, the carbon layer has other options such as a media reactor, and the biological layer used refugiums or other biological filter media. It makes more sense to keep these separate because they need to be changed at different times. With the difficulty of maintenance, usually canister filters don't get the attention needed and lead to more nitrate and phosphates.

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About the Author

Reef Stable Founder John Krenzer

John is a Software Engineer with a passion for saltwater aquariums, as well as the founder and president of Reef Stable. He started in the aquarium hobby as a child with a 20 gallon freshwater aquarium. His interest in aquarium life grew and in 2008, John set up his first saltwater aquarium.

Today, John maintains an over 300 gallon reef tank system, consisting of a 120g reef and a 210g reef. These large tanks are contained within the same system, sharing a sump as a means to reduce total maintenance and increase total water volume.

John writes articles for the blog as a means to learn about more reef aquarium topics. These articles act as a reference for the readers as well as himself. John updates these articles frequently to provide additional information or make corrections as new information becomes available.

If you would like to request an article, tank tour article, or to collaborate, let me know via the Contact Me Page!

About Reef Stable

Reef Stable was initially founded in 2019 as a reef tank parameter log to fill a need. Reef Stable quickly grew, becoming a location to solve all of your reef tank problems as well as a place to learn.

Reef Stable now provides a Reef Blog, Reef Aquarium Guides, Coral Care Guides, Identification and Solutions for Pests and Algae, and Reef Dosing Calculators, in addition to the original Reef Parameter Log.

Reef Stable continues to grow, striving to provide a single location for all your reef tank needs!

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