Flatworms can devastate a reef tank. Polycladida is a highly diverse group of marine organisms, which include beautiful species, on down to the nasty little creatures known for consuming acropora colonies. Flatworms all found all throughout the ocean, from around deep-sea hydrothermal vents to coral reefs. In the wild, flatworms associate with corals, clams and mollusks for several reasons, sometimes for food and sometimes for protection from predators. There are lots of them in the ocean, and often they arrive on live rock and embedded within coral colonies. While good husbandry practices (quarantining and dipping new coral arrivals) can help prevent a flatworm infestation, for average reef keepers, sooner or later we are likely to discover the little worms crawling around our tank.
Sadly, it’s often not the intensely colored individuals featured in oceanic documentary films, but very bland and tiny species, that appear like little moving specks sliding along the aquarium glass. If you see groups of flatworms on the aquarium glass, then it’s without a doubt they are living in and around your corals as well. The order Polycladida is split into two sub-orders, Cotylea and Acotylea, based on the presence of a cotyl (or sucker). Of the two suborders, Acotylea is the most prolific and also a major predator of sessile marine invertebrates, including our beloved corals. These flatworms are dull in color and cryptic in behavior, most likely to be spotted at night as the lights are going out. It’s likely if flatworms are encountered in the aquarium, they are in-fact of the Acotylea sub-order and being voracious coral predators, they must be eradicated.
Flatworm exit and Brightwell Aquatics Carbonit X-3:
Most aquarists confronted with a flatworm infestation turn to Sailfert’s Flatworm Exit. It’s inexpensive, easy to use and considered reef safe if proper protocol is followed. Using Flatworm Exit is a multi-step system, and in order to protect your aquarium’s life, it’s best to error on the side of caution. When flatworm’s die, they emit a toxin. Considering most flatworms are almost invisible to the naked eye, a few dying is unlikely to release enough toxin to effect other life within the aquarium. When hundreds or thousands of flatworms die, it can spell disaster.
Damage control when dosing Flatworm Exit involves both removing as many dead flatworms as possible, and completing a large scale water change (around 35% of total system volume). It also involves vigorously running activated carbon to absorb as much toxin as possible. Usually, if I treated my tank with Flatworm Exit, I would fill a fluid reactor with Rox-8 grade carbon and also lace a filter sock with carbon. This way flatworm laden water passing into the sump was filtered through carbon, and water returning to the aquarium was passed through a carbon reactor. In the sump’s middle, the protein skimmer is removing organics and hopefully flatworm toxin as well.
A while back, I stumbled upon Brightwell Aquatics Carbonit X-3. It’s advertised as a “next-generation, enhanced activated carbon, offering superior filtration over traditional activated carbon.” Brightwell also claims it’s triple action removes ammonia, chloramine and any latent organic material. Furthermore, it’s said to enhance oxidation reduction potential (ORP) by effectively stripping the water of organic matter. Sounded like powerful stuff, so I picked some up to run in my usual carbon reactor. Upon firing the reactor loaded with X-3 up, I immediately noticed a quick rise in ph. Not a minimal rise, but ph running from 8.23 to 8.77 within a half an hour. I shut the X-3 reactor down, and called Brightwell Aquatics. After several days of playing phone tag, I finally got in touch with one of their techs.
In additional to other contaminants, X-3 rapidly removes CO2 from the water, thus raising the aquarium’s overall ph. It’s not intended for constant use in a reactor, unless an aquarium is overloaded with CO2, to the point the ph is remaining consistently low. According to Brightwell, when used for just 45 minutes a day, X-3 can accomplish what traditional carbon does running all the time. It’s powerful stuff, and likely not something any aquarist needs running 24/7.
However, a few days later when I noticed flatworms sliding across my aquarium glass, I found the perfect use for Carbonit X-3.
Using Flatworm Exit with X-3:
The first step to using Flatworm Exit to kill off a Polycladida infestation, is having around 35% of your aquarium’s water volume mixed up, ready for a water change. During treatment, you’ll be acting quickly to remove flatworms, which in turn removes a lot of water. I recommend keeping an extra, empty reactor and pump on hand, that can be loaded with X-3 and easily hooked up, in the event you’ll need to treat for flatworms (you will likely be treating for them, sooner or later). Get the reactor loaded up and ready to switch on, and make sure the mixed saltwater is ready for action.
When starting treatment, I turn everything off except circulation pumps and the main system pump. You want the sump loaded with Flatworm Exit as well, since it’s likely worms are inhabiting it as well. Flatworm Exit is dosed by drops, and usually after the entire dose, within five minutes’ flatworms start dying. As soon as flatworms are floating around the tank, kick on the protein skimmer. It’s now that the breadth of infestation will be obvious, as often flatworms are floating everywhere in the aquarium. Work quickly, using a siphon hose to remove as many dead flatworms as you can. I work until I’ve filled a 30 gallon container with water, then pump that water out and see if the worms are still dying. If they are, keep working to remove them. If not, do a partial re-dose of Flatworm Exit, just to clean up any stragglers. Usually at this point, you would kick on an activated carbon reactor to begin removing toxin, which also removes the Flatworm Exit. Since the reactor is loaded with X-3, you can hold off and allow the Flatworm Exit to have maximum efficiency.
After another round of siphoning out flatworms, it’s time to kick on the X-3 reactor. It’s likely you will notice the same ph increase I did, as along with toxin and Flatworm Exit, the X-3 is pulling out CO2. According to Brightwell, the rise in ph shouldn’t concern aquarists too much, unless you are running X-3 constantly, which is something they seemed to advise against. However, Brightwell did say that after 24-48 hours and upon the carbon reaching saturation, the ph rise will taper off and drop back down. X-3 is also said to raise ORP levels in the aquarium, as it rapidly absorbs organics from the water. I didn’t notice any ORP improvements, however I run ozone on my reef, so the ORP is already elevated to begin with.
Once X-3 is running and has had enough time to turn over the volume of water left in the aquarium at least once, the water change can be completed. I recommend running the X-3 reactor for a few hours afterward, to pull out any toxin absorbed as flatworms may continue to die.
It seems apparent that Brightwell’s Carbonit X-3 has an advantage over traditional activated carbon, when it comes to removing organics, treatments and toxins from aquarium water. It may be that the product is too strong for use in a continuous carbon reactor, and could possibly pull out any trace element or needed additive. Another use for X-3 I am experimenting with, is maintaining the water clarity and appropriate ORP of mixed saltwater. I often mix saltwater in a 70 gallon drum and then use it as needed, for water changes and anything else. Even when the water is constantly circulated with powerheads and heated, it seems like after a while it loses its clarity. Using a powerhead with an attached quick filter and carbon is handy at keeping mixed water clear. The X-3 might be an even better option, as the water would retain a better than average ORP. However, it will take a fair bit of testing to determine if the X-3 pulls out any valuable elements from newly mixed saltwater.