Chemistry Behind Pax Bellum ARID Algae Reactor

What is the A.R.I.D. system? If you just asked yourself that you’re not alone. A.R.I.D. stands for, Algae, Remediation, Illuminated, Device and is the culmination of more than a decade of research and development, resulting in both a US patent 9388372 and international patents pending. What does the A.R.I.D. do? The A.R.I.D. has the capability to drive down phosphate to levels required for vigorous SPS coral growth without the need to constantly buy and replace chemical media.

Biological Stoichiometry

This biological filtration system works on the principle of what Pax Bellum LLC like to call “biological stoichiometry”; the balance of products and reactants in a biological system by use of a biological medium as a nutrient export, in this case algae. The A.R.I.D. is capable of targeted nutrient export by growing macro-algae. In the reef aquarium the main concern is balancing the nutrients N:P:K:C, with the goal of limiting phosphate (P). Potassium (K) and carbon (C) are usually never in short supply.

 

However, nitrogen (N) can become depleted by the growth of the algae, causing its growth to stall. To keep the algae growing, the aquarist should dose the nitrate solution that is part of the A.R.I.D. system, maintaining the NO3 level at around 100:1 ratio to phosphate (example 3ppm NO3: 0.03ppm PO4). This will allow the Chaetomorpha or macro-algae of choice to continue to grow until phosphate levels are depleted.

Balance is everything.

Maybe you caught that we previously said the A.R.I.D. system requires the dosing of nitrates from time to time. We hear it often; “dose nitrates? Are you kidding? Don’t I want to get rid of nitrates; I mean that’s what I’ve been told time and again, right?” Well yes, and no, nitrates have earned a bad reputation through guilt by association. When food is introduced into an aquarium it is an added source of phosphates, nitrates and carbon compounds. Nitrates in the past were all aquarists could test for accurately to determine nutrient build up. Aquarists in the ‘90s and early 2000s didn’t have the accurate phosphate tests available today.

 

So when nitrates rose in reef tanks and coral growth slowed or worse, nitrates were blamed when in fact it was elevated phosphate and/ or organics levels disrupting coral growth. Reef aquarists want to keep nitrogen, as with all nutrients, in a constant state of cycling with emphasis on holding a specific ratio not so much a specific concentration. The key to a healthy reef is balanced ratios of these nutrients and constant flow of the nutrients in and out of the system with organisms’ as reservoirs for these nutrients.

Limiting the Carbon Source for Algae

In a refugium the algae is pushing through the water meniscus and interacts with atmospheric CO2. The A.R.I.D. limits the carbon source for the algae to mostly that which is respired by the organisms found in the tank. This regulates the growth of the algae and organics that the algae leak into the water leading to water yellowing often associated with refugiums.

 

Compounds that algae leak include sugars (polysaccharides) that aerobic bacteria consume. These bacteria can be found colonizing the surface of the Chaetomorpha, and will play a role as a nutrient export when they are rinsed away during the maintenance procedure. Polysaccharides additionally benefit the aquarium by functioning as a flocculent, binding to organics to precipitate them out of the water column, resulting in water that is crystal clear.

Breathe Easy

The A.R.I.D.TM acts like a lung for your reef tank. Unlike a skimmer that equilibrates the O2 and CO2 levels to that of the surrounding room, (a room that is often much higher in CO2 levels than found above a natural reef). The A.R.I.D. supersaturates the tank with O2 much like phytoplankton does in the surface waters of the ocean. Another benefit from running the A.R.I.D. on your reef aquarium system can be realized by running the light cycle reverse to your tank lighting (reverse daylight cycle). Reverse daylight cycle will balance the day/night ph swing, and maintain dissolved oxygen levels throughout the night when your main
tank lights are switched off, and photosynthesis has ceased.

Other Facts About the A.R.I.D.

Hot stuff….All A.R.I.D. models utilize a heat pipe and heat sink to extract excess heat from the LED light assemblies. This does much more than obviously keeping excessive heat from entering your systems’ water. Likely at some point you have looked at an aquarium heater and noticed it is encrusted in scale. This is because as temperature rises carbonates precipitate out of solution and deposit on the surface of the hot heater element. Without adequate cooling the light tube would become encrusted like a heater in a few days blocking a large amount of light from reaching the macro-algae. A light tube without cooling would require weekly scraping or an acid bath to remove the scale. Who wants to deal with that? Heat will also burn any algae in direct contact with the light tube, and should the pump flowing water through the chamber fail the water temperature would rise rapidly to cook the algae contained within.

We’ve Tried it All

Having reduced the temperature of the light assembly the A.R.I.D. can use polycarbonate for a light tube in place of fragile quartz sleeves. Anyone that has run a UV sterilizer has eventually had an incident where they broke a quartz sleeve during maintenance, or worse it broke at the seal when the temperature gradient became too high due to a pump going down. Broken glass in water is never fun or safe to clean up. Polycarbonate on the other hand can handle a service temperature of 220F and handle impact and flexing. Polycarbonate will not last forever and does have its disadvantages. The polycarbonate light tubes of the A.R.I.D. should be replaced at least once a year due to scratches and aging from thermal cycling and oxidation. Even with a limited life span, polycarbonate will fail slowly and not abruptly like shattered glass. Signs of thermal fatigue will be noticed long before complete failure. Replacement tubes are available here and include replacement seals for the lid.

High Design

At Pax Bellum LLC we believe form follows function. That doesn’t mean the form has to be unappealing. Function is inspiration for the many forms throughout the A.R.I.D. product line. One example is the unique gear shape of the flange and lid. The gear shape is more than simply an aesthetic design choice; the shapes are made to facilitate easy one- handed opening of the chamber. Another example: Instead of just having the water enter the base through a crude hole drilled into the side wall of the chamber, the base of each model is made to appear to levitate above the floor hiding the plumbing that enters directly through the bottom center of the base. Not just an appealing illusion of levitation, this arrangement forces water entering the chamber to first be deflected off the cap on the bottom of the light tube, spreading the water pressure evenly 360 degrees under the first baffle plate and creates a laminar flow as it pushes through the algae.

 

If the water was to enter from the side it would shoot straight across the chamber hitting the far wall creating a high pressure zone on one side of the chamber. Water would then flow up the high pressure side of the chamber faster creating a low flow, low pressure zone around the inlet port. Algae in the low flow, low pressure area would not grow as well or even possibly die off. These are only a few examples of form following function found throughout A.R.I.D. systems.