Tenji is pleased to present a series of exclusive articles for Reef2Reef members. We will be delving into the various aspects of reef keeping, focusing on tried and true methods that can be implemented by aquarists of all levels.

Choosing your display aquarium is the most important equipment decision you will make. If the display fails, everything else is all for naught. The two basic material choices we have for aquariums under 500-gallons are glass or acrylic.

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Tenji installation in a private residence.

Generally speaking, glass aquariums under 180-gallons will be me affordable than acrylic aquariums of the same size. Of course, there’s more than just cost to consider here. Acrylic tanks are much easier to scratch, but scratches can be removed. Glass tanks are significantly harder to scratch, but if they are, you’re pretty much stuck with it. Glass tanks are generally heavier than acrylic tanks which can be a logistical and structural concern once you reach larger volumes. There’s a rumor floating around that acrylic tanks are stronger than glass tanks, however, historically we have not found that to be true for aquariums under 500-gallons. We have seen tanks of both materials fail. Longevity ultimately comes down to the bonding process and thickness of the material used. A properly built glass tank will greatly outlast an improperly built acrylic aquarium.

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If you’re looking at a glass aquarium you’ll get into the age-old debate of regular glass versus starphire glass, or low-iron glass. While starphire is more clear than regular glass, it can scratch easier and costs quite a bit more. We’ve never seen a stunning reef aquarium and shunned it for not being starphire; a stunning tank is a stunning tank no matter the material. More often than not we’ll lean towards standard glass, especially for ½” or thinner material.

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No matter your choice, the thickness of the material should be your main concern. The thicker the material, the more surface area for bonding is available. Thus a 180-gallon aquarium built with 5/8” thick glass will be stronger and last longer than a 180-gallon aquarium built with ½” glass by the same manufacturer. Of course, the thicker the material the higher the cost. We highly recommend avoiding tanks built with the minimum recommended thickness.

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Hybrid aquarium from MRC.

We’re faced with a few more options when it comes to bracing. Note that the purpose of trim is to protect the glass from chipping, and ourselves from getting cut (most glass is not beveled/polished under trim), and to prevent panes from bowing if material thickness is lacking. Most standard tanks are braced with molded plastic trim. Step-up from that and we begin to see acrylic, PVC, aluminum, and steel braces offered. My personal favorite is dubbed a hybrid aquarium, which is a glass tank that has CNC’d channels in a PVC bottom and acrylic top that the glass panes fit into. Not only do the one-piece top and bottoms provide phenomenal support, but the CNC’d channels lock the panes in place and allow silicone to bond to three sides of the panes. Rimless tanks are built with thicker material since there is no bracing, and glass edges are beveled or polished for safety and aesthetics, creating a higher price point than their braced counterparts.

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Commonly offered "reef ready" tank with ABS overflows without tops and undersized bulkhead holes.

Finally, we get into the overflow and bulkhead choices. We greatly prefer acrylic overflows since we can choose colored acrylic to help hide the boxes against a matching background. Textured overflows, such as those made from ABS, require frequent cleaning to keep them looking good since a scraper won’t bring it back to life if neglected, although if you plan to let animals or coralline grow on it ABS might be preferred. Glass overflows generally leave some plumbing exposed, which causes our eyes to twitch. Most off-the-shelf reef ready tanks come with undersized bulkheads, and none of them allow for SCH80 bulkhead installation which should be standard for those in it for the long-haul. Furthermore, mass-produced tanks frequently miss simple things like having the overflow come up to the top to prevent trapping fish (see image below), or even including an overflow top to keep said fish in the tank.

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This wrasse was trapped between the screen top (not pictured) and overflow top.

At the end of the day, structural integrity should be your number one concern. A seemingly cheap tank will likely be constructed of thin material that probably won’t end well long-term. We commonly hear to purchase the largest tank you can afford. We say cut that size in half, so you can get into a quality tank and have funds left for quality equipment. A well-built life-support system will cost the same, if not more, as your display aquarium.
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