Micro Bubble Scrubbing in the Reef Aquarium

What is Micro Bubble Scrubbing?

Micro bubble scrubbing, also known as the bubbling method or micro scrubbing bubbles, appears to have originated by Elegant Corals in 2015. The concept itself is quite simple, allow a large number of micro and nano bubble to enter the aquarium, and the bubbles will handle the rest. There are a variety of possible benefits, though there are always concerns as well.

Micro bubble scrubbing is not widely utilized in the saltwater aquarium hobby at this time, as some of the benefits are difficult to measure and there is a large amount of concern for many aquarium owners about introducing bubbles to the aquarium. Another concern is that it can be difficult to see, or even measure many of the benefits, as they are focused around prevention and optimizing ph, which changes frequently thorough the day. Though the original concept was based on maintaining stable PH in reef aquariums, there have been additional benefits as well.

What are the Benefits of Micro Bubble Scrubbing in Saltwater Aquariums?

To start determining the benefits of Micro Scrubbing Bubbles for Reef Tanks, we should look at the benefits published in the original post by Elegant Corals.

Facebook - Elegant Corals, LLC - July 22, 2015

Elegant Corals "Micro Scrubbing Bubbles" Technique for the Reef System... :)
Allows the corals to release excess slime and waste...
Allows the coral membrane to breathe and allow for better osmosis and ion exchange with the water column...
Oxygenates the water and de-gasses excess CO2 in the water column out of the system. (Skimmers and a little ball of chaeto is not sufficient... sorry...)
We recommend 8 to 10 hours a day counter cycle for the first week, then 2 to 3 hours a day counter cycle to the display tank lighting to maintain a more consistent and stable pH level.
The correct pH greatly improves the calcification rates of all hard corals...
Oxygenation also assists in higher beneficial aerobic bacterial loads as well as decrease the bad anaerobic cyanobacteria that many hobbyists struggle with.
The micro bubbles also get under (with proper tank flow) dinos and the cyanobacteria and carry them to the over flow to be removed by an efficient skimmer.
Not just for gas exchange or CO2 degassing... part of the nutrient cycle/export system, as well... excellent water flow is needed and vital to prevent the mucus from a neighboring colony to suffocate or burn another. Quick removal with a turkey baster is suggested for stuck on stubborn mucus.
NOTICE: NO FILTER SOCKS IF YOU HAVE A TRUE WORKING REFUGIUM!!
If fighting dinos, cyanobacteria, or other Reef Tank Pests, we will be adding it to our "NOTES" section in the near future!
CHEERS!

The primary focus was CO2 degassing, though this is the largest benefit of micro bubble scrubbing in reef tanks, this is just the beginning.

Micro Bubble Scrubbing Benefit 1:

- PH Stabilization & CO2 Degassing

As mentioned by Elegant Corals, the first of the major benefits of micro bubble scrubbing method is removing excess CO2 from the water. CO2 is created when the fish, invertebrates, and other aquarium life exhales; very much like how we humans exhale CO2. The major difference is the CO2 from your fish is trapped in the aquarium. This would be like being trapped in a small room for a long period of time, eventually the air quality will decline if you don't introduce fresh air. If we take our air quality so seriously, why don't we do the same for our aquariums? It is our pets' home after all.

Dr. David Koweek conducted a study while working toward his PhD. using bubble scrubbing in the ocean's reef and found benefits on a large scale as well. He also found that the CO2 concentration would increase after the sun set for the day. This means that just before the sun would rise, the CO2 concentrations would be at their highest levels for that day.

Okay, I get it, we don't often measure CO2 in Saltwater Aquariums, or do we? Higher concentrations of CO2 will cause the reef tank's water to become more acidic, meaning a lower PH. Many advanced reef keepers and coral propagators try to keep their aquarium PH around 8.0 - 8.4, if the water becomes acidic, the ph will decline. This poor PH level could cause coral growth to slow, as well as possibly lead to health issues for fish and invertebrates.

Let's summarize the CO2 and PH benefits before moving forward with more benefits of micro bubble scrubbing. Fish and coral exhale CO2 in the water at night. High CO2 concentrations in the water leads to a decrease in the aquarium's PH levels and can inhibit coral growth, and even become toxic for aquarium inhabitants. Micro bubbles blasting through the reef tank helps remove the CO2 from the aquarium and helps stabilize PH in your reef tank.

Even if the only benefit were CO2 degassing, the simplicity and low cost of micro bubble scrubbing makes it worth the investment.

Micro Bubble Scrubbing Benefit 2:

- Removing Waste from the Aquarium

CO2 degassing is not the only benefit of micro bubble scrubbing in saltwater aquariums. Another benefit of the micro scrubbing bubbles technique that it helps remove waste from the aquarium. When filling the aquarium with these micro bubbles, uneaten food and other fish waste in the water column will bind to the bubbles and float to the top. This fish waste gets carried to the overflows and caught in your filter socks, refugium, protein skimmer, and/or other filters. The micro scrubbing bubbles technique works very similar to that of a protein skimmer, using your entire tank. It won't replace your protein skimmer as there is a much lower bubble density, but bubble scrubbing will help remove some of these nutrients from your aquarium.

To supplement this nutrient removal, you may need to increase water flow to help move the waste from the sand bed and rock surfaces in to the water column where the micro bubbles can remove it. This is a common flow profile in the Ecotech VorTech wave makers, known as the nutrient transport function. Simply put, this mode moves the waste from where ever is settled back to the water column where the bubbles can help remove them.

Micro Bubble Scrubbing Benefit 3:

- Coral Mucus Removal

Corals produce a mucus to protect themselves, however this can trap debris and even remain on the coral after its beneficial use. Even worse, the mucus can contact nearby coral colonies and either suffocate or sting them, causing damage or death of the coral. Similar to the nutrient removal benefits mentioned above, the micro bubble scrubbing method can assists in the export of this mucus, enhancing coral growth potential and overall health.

What are the Negative Effects of Micro Bubbles in Saltwater Aquariums?

Just like anything else, with any benefit, there can be negative effects.

Micro Bubble Scrubbing Risks:

- Coral Trapping Air

Corals can trap the bubbles in their polyps, within the colony, or even under larger corals such as montipora caps, leading to die off in those areas as it can be similar to removing that section of coral from water. Though you can't prevent this risk entirely, there are ways to minimize the risk. The simplest of these is by just having strong water flow, preferably with a varying wave pattern, to remove the bubbles. Running the nutrient transport flow profile in the Ecotech VorTech wave makers for 10 to 15 minutes after the bubbles are turned off can remove the majority of bubbles that get trapped.

- Fish and Coral Irritation [MYTH]

Though in extreme cases, it is true that fish and coral can be irritated by micro bubbles, an article by Reefkeeping Online Magazine reminds us that "Small bubbles are very common in tumultuous reef environments, and areas where waves break are often dense with both reef life and small bubbles.". The reality is that though it is possible that there is some risk, it seems very unlikely that a few hours of bubbles per day will cause unhealthy irritation to your aquarium. This is especially true if your fish have ample places to hide and sleep.

How to Set Up Micro Bubble Scrubbing in Saltwater Tanks

The setup for Micro Bubble Scrubbing in Reef Tanks is rather simple, and quite inexpensive. Here is a list of what you will need:

• Wooden Air Stone
• Air Pump
• Airline Hose
• Airline Check Valve
• Outlet Timer
• Glass, Plexi, or Acrylic tops for the Tank

Step 1: Wooden Air Stone

Start by connecting the wooden air stone to the air tubing. Then place the air stone under the inlet to the return pump. Make sure to attach it to the pump, rock, or other fixed object using a zip tie or magnet to keep the air stone from getting sucked in to the return pump while forcing the bubbles to go enter the return pump. If you don't have a sump, or have an all-in-one tank, you can attach the air stone to the underside of a powerhead or wavemaker within the tank.

Though most air stones will work, wooden air stones tend to produce finer, smaller bubbles. Since the goal of micro bubble scrubbing is to utilize the smallest bubbles possible, the wooden air stones are a better tool for the job. If wooden air stones are not available, however, a standard 1 or 2 inch air stone will work until you can get a hold of a wooden air stone.

Step 2: Connecting the Air Pump

When connecting the air pump, I HIGHLY recommend placing the check valve just past the location where the airline comes out of the sump or tank. The check valve prevents flooding if a siphon were to occur. I know what you're thinking, I didn't think this would happen either. Let's just say if you don't use a check valve, you'll need a mop, or more likely a wet-vac. When the airline forms a siphon, there will be a lot of water lost and a lot of damage. So for less than $3, this will save you a lot of damage, money, and coral loss as well.

After the check valve, just connect the air pump and test it out! Your tank should be blasted with small bubbles. If the bubbles are not being sucked in to the return pump, you may need to adjust the location of the air stone until it sucks in all of the air.

Step 2.1: Fresh Air for Optimal PH Balancing

The reason I encourage something like the Aqua-Lifter is because it has an inlet that lets you connect an air hose to decide where you want the air to come from. Though you are not required to connect the second air line, it is nice to have if you find that the air is not as fresh near your tank as, say, outside. If the outdoor temperature is not too high or too low (Ideally in the 70-80 degree range) you can pull in fresh air to better remove CO2 and lead to better PH levels in your saltwater tank. If this is not the case (like most of us) then you can run the line to a different part of the room or even another room to pull fresh air from a different part of the house. If you do not plan to do this, any other strong air pump should work, as long as you size it appropriately for your tank size.

Step 3: Set up the Timer

The final step is setting up the time to turn on the bubble scrubbing. The best time, the point in which the highest CO2 concentration is in the water and therefore most available to be removed, is the 2 to 3 hour window before the aquarium lights turn on. Initially you should aim to run the micro bubbles for at least 2 hours before the light come on to remove the CO2 from the tank. If it doesn't bother your fish or corals, I would even recommend running the stone for 15 minutes per hour while the lights are off. This will help keep your reef parameters more stable throughout the night.

FishOfHex - Setting Up Micro Scrubbing Bubbles In A Reef Tank

If you don't want to take it from me, and Elegant Corals, then I will add another well know saltwater tank influence, FishOfHex, who also utilizes micro bubble scrubbing for his reef aquarium.

BONUS: Remove Extra Waste

If your powerheads have a nutrient transport or cleaning mode that pulls waste off the bottom of the tank, rocks, and/or sand, pairing it with bubble scrubbing will benefit your aquarium even more! If you do the nutrient transport cycle at the same time as the bubble scrubbing, the first benefit is that the bubbles can help bring more debris to the top of the tank and into the sump where the filter socks or protein skimmer can remove it. Additionally, it can remove the CO2 more uniformly from the tank. Finally, doing this helps SPS corals shed their mucus better, leading to healthier corals.

Other Considerations

In addition to using a check valve to prevent flooding, there is one other major consideration. When using micro bubbles to clean your reef tank, there will be a lot of spray from the bubbles rising to the surface. This can lead to water or salt damage on the light or nearby walls, as well as higher humidity and things from the tank to become airborne. How do we fix this? Simple. You will NEED glass tops on your tank to prevent any damage from the water spray and salt creep. You can purchase glass, plexi, or acrylic sheets from a local hardware store relatively cheap.

Conclusion

As we covered in this guide to micro bubble scrubbing for saltwater tanks, there are a variety of benefits to implementing bubble scrubbing for the long term success in your reef tank. From CO2 degassing and PH stability to fish waste and coral mucus removal, micro bubble scrubbing is one of the many hidden gems of the reefing community. The benefits far outweigh the risks, and the risks are minimized much further by coupling your micro bubble setup with strong flow. For the low cost, I highly recommend you go to the list above and implement micro bubble scrubbing for your reef tank today!

References:

• Elegant Corals - Facebook - Original Post
• Advanced Aquarist - Air Bubbles To Improve Reef Water Chemistry

Recommended Reading:

• Saltwater Aquarium Lighting Guide
• Saltwater Aquarium Filtration Guide
• Determine Flow Rate in the Reef Tank
• 5 Best Filters for Saltwater Tanks

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About the Author

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 a 120 gallon mixed reef aquarium as well as a 210 gallon aggressive species aquarium. 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.

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