A traditional layout with a complete equipment package
Red Sea REEFER MAX 425 G3: My 91-Gallon Saltwater Aquarium Build
If a peninsula aquarium does not appeal to you, or you do not have the room to enjoy both sides of one, I would take a look at the Red Sea REEFER MAX 425 G3. You get a larger display in a more traditional layout, with almost the same equipment package as the Peninsula 350 G3.
I still prefer a peninsula, but that does not mean it is the right choice for every home. This is how I would put the 425 G3 together and the extra gear I would buy. It is a proposed build, not a tank I am claiming to have personally set up.
My verdict
The one I would choose if a peninsula does not fit
The main reason I would choose this over the Peninsula 350 is the layout. If you want a more standard reef tank against a wall, or just do not have space to make use of a peninsula, this is a great system to consider.
You get a roughly 91-gallon display and a lot of good equipment. There is not much to complain about here beyond my usual preferences for an acrylic sump, an external overflow, and a different lighting combination.
What comes with the aquarium
A lot of the expensive gear is included
The tank, cabinet, sump, plumbing, and main equipment arrive as a matched package. Compared with the Peninsula 350, the big changes are the traditional display shape, extra water volume, and separate light mounting arms.
Red Sea REEFER MAX 425 G3
The display measures 47.2 inches long, 23.6 inches wide, and 21.7 inches tall. It holds 90.6 gallons, with a listed total system volume of 114.4 gallons. That is about 17–18 more display gallons than the Peninsula 350.
- Aquarium and matching cabinet
- Sump and pre-glued plumbing
- Two ReefLED G2 115 lights
- Two separate mounting arms
- REEFER DC 600 protein skimmer
- Two ReefWave 45 gyre pumps
- ReefRun G2 6000 DC return pump
- ReefRun controller
- ReefMat 500 fleece roller
- ReefATO+ auto top-off system
- Slide-Out Control Panel 60
The freshwater reservoir, heater, and general-purpose Wi-Fi AC outlets are not included.
What I like
A great system in a more familiar shape
Equipment-wise, there is very little separating this from the Peninsula 350. I would make the decision based mainly on which shape works better in your home.
A traditional reef tank layout
If you cannot make use of two long viewing panels, there is not much reason to arrange your room around a peninsula. The 425 gives you a wide front view and a familiar rectangular footprint.
No ceiling-mounted pendant
Both systems come with two lights, but the 425 includes a separate mounting arm for each light. You do not need to hang and center a pendant from the ceiling, which makes installation simpler.
Controllable pumps and filtration
I like that the package includes a DC return pump, a DC skimmer, two gyre wave makers, and a fleece roller. These are good products, and I do not have to choose all of them separately.
A matched Red Sea system
Red Sea makes a good product. You are buying equipment designed to work together, with the compatible smart gear managed through ReefBeat. That is a big part of the appeal of this package.
What I would change
My usual preferences still apply
None of these would stop me from recommending the aquarium. They are just the things I would choose differently if I were building everything from scratch.
I would add bar lighting later
The two ReefLEDs are good lights and will work fine. They are just not my favorite style for this tank because puck-style lighting can cast shadows as corals grow. I would prefer a combination of puck lights and strip lights. You can always add that later.
I prefer an acrylic sump
The included glass sump works with the equipment supplied. I personally prefer the lighter weight and layout options of acrylic sumps, but there is no need to replace this one just to get started.
I would rather have an external overflow
I am not a big fan of having the overflow box take up space inside the display. I would prefer an external overflow, but this internal design is part of the system and is not a deal-breaker for me.
The full setup costs more than the tank
The package comes with tons of gear, but it does not come with everything. You still need a reservoir, heating and testing equipment, water-making supplies, sand, rock, and the smaller items below.
ReefBeat control does not mean Wi-Fi outlets are included
The included Red Sea smart equipment works through ReefBeat, and the ReefRun controller operates compatible pumps. The package does not list a ReefControl Pro or ReefControl Power 8. The slide-out control panel is a mounting surface for electronics, not a controllable outlet strip.
I would start with the Inkbird to control the heater. Later, I would consider ReefControl Pro and Power 8 Deluxe for additional monitoring, controllable outlets, and coordinated feeding and maintenance routines.
Other items you will need to purchase
The rest of my shopping list
You do not need to buy another light, skimmer, return pump, wave maker, fleece roller, or ATO system. Here are the other items I would add. Choose the size named on each card when the product page offers multiple versions.
Innovative Marine Aqua Gadget 15-Gallon Hydrofill Reservoir
For a system this size, I would choose a 15-gallon reservoir. I like the pull-out refill drawer and the easy-to-see water level. It measures 18.2 × 12.2 × 23 inches. Measure the available cabinet space, door opening, and refill-drawer clearance before ordering; I have not confirmed an inside-cabinet fit for this reservoir.
View the 15-Gallon Reservoir at BRS
BRS 300-Watt Titanium Heater Element
The 300-watt element carries over from the Peninsula shopping list, but check the sizing before buying: BRS rates it for up to 100 gallons, while this system is listed at 114.4 gallons including the sump. Actual water volume and room temperature matter. Confirm the appropriate wattage with BRS; pair the element with a controller and keep it fully submerged.
View the 300W Heater at BRS
Inkbird ITC-308 WiFi Dual-Stage Temperature Controller
This controller switches the heater on and off to maintain your chosen temperature. It also has high and low temperature alarms, WiFi monitoring, and a separate cooling outlet if you add a fan or chiller later.
View the Inkbird ITC-308 WiFi at BRS
Refractometer with Calibration Fluid
Use this to mix new saltwater and confirm the aquarium stays at the right salinity. Calibrate it with the included 35 ppt solution before relying on the reading.
View the Refractometer at BRS
Python 2-Inch Large Pro-Clean Gravel Wash
Choose the Large version with the 16-inch gravel tube, not the Medium with its 10-inch tube. I would use the longer tube for water changes and sand cleaning in this deeper aquarium. The BRS page lets you select the size.
View the Gravel Wash at BRS
Flipper EDGE Max Magnetic Algae Cleaner
The front glass is approximately 12 mm (0.47 inch), but the side panels are approximately 15 mm (0.59 inch). The EDGE Standard is rated up to 12 mm, so I would choose the Max, rated up to 24 mm, to clean both the front and sides. Both EDGE sizes have dual blades; I like that design for quicker cleaning. Keep the blades away from silicone seams.
View the Flipper EDGE Max at BRS
HelloReef Stick-On Thermometer
This simple thermometer stays outside the aquarium and gives you a quick temperature check every time you walk by.
View the Thermometer at BRS
API Saltwater Master Test Kit
Testing ammonia and nitrite tells you when the nitrogen cycle is complete and it is safe to begin adding animals.
View the API Test Kit at BRS
Dr. Tim’s Ammonium Chloride
This gives you a measured ammonia source for a clean, fishless cycle. Follow the label carefully and confirm the dose with your ammonia test.
View Ammonium Chloride at BRS
Dr. Tim’s One & Only for Saltwater
Add the nitrifying bacteria after dosing ammonia chloride. Choose a bottle sized to treat the full water volume of this approximately 114-gallon system, including the sump, and follow the label.
View One & Only at BRS
BRS 4-Stage Value Plus 75 GPD RO/DI System
For this build, I would buy a full RO/DI system. It gives you clean water for mixing saltwater and for every future top-off.
View the RO/DI System at BRS
Tropic Marin Pro Reef Salt
This is the salt mix I would use for the build. Mix it with RO/DI water and use the refractometer to verify salinity before adding it to the tank.
View Tropic Marin Pro Reef Salt at BRS
CaribSea Original Grade Ocean Direct Live Reef Sand
I would plan on about 80 pounds—four 20-pound bags—for this aquarium. You may use less if you prefer a shallower bed. Add the sand to the depth you actually want, rather than feeling obligated to empty every bag.
View the Live Sand at BRSCheck the reservoir and heater before ordering
The 15-gallon Hydrofill reservoir is my preferred capacity here, but confirm its 18.2 × 12.2 × 23-inch dimensions against the actual cabinet opening and available service space. Do not reuse the Peninsula cabinet measurements for this tank. Also confirm heater wattage using the full working water volume and your coldest room temperature.
Rock and aquascape
Give the animals room around the rockwork
I would buy around 80 pounds of Original LifeRock and add a couple of arches. The smaller options below are just that—options. Try the design outside the tank first and do not pack every piece into the display.
CaribSea LifeRock Dry Live Rock — 40 Pounds
I would start with two 40-pound boxes, giving me 80 pounds to choose from. You could buy up to 100 pounds if you want more choices, but do not use extra rock just because you bought it. Leave room for swimming, cleaning, and coral growth.
View LifeRock at BRS
CaribSea Arches LifeRock Dry Live Rock
I would work a couple of larger arches into the design. This product is sold as a 20-pound box, typically with four arches, so one box gives you pieces to choose from. Use the two that work best and save the rest if you do not need them.
View LifeRock Arches at BRSOptional smaller pieces
CaribSea Nano LifeRock — 10 Pounds
Optional: one 10-pound box gives you smaller pieces for filling out the aquascape and creating little nooks and crannies. I like having those choices, but you do not have to buy this as well as every other rock option.
View the Nano LifeRock at BRS
CaribSea LifeRock Nano Reef Kit
Optional: this kit includes two nano arches and a small piece of Original LifeRock. It is another way to add smaller shapes to the aquascape without committing to another large box of rock.
View the Nano Reef Kit at BRS
CaribSea LifeRock Nano Arches
Optional: the four smaller arches in this pack give you more ways to create caves and swim-throughs. Choose this or the Nano Reef Kit if you want smaller accents; neither is required to make the main aquascape work.
View the Nano Arches at BRSSecure the aquascape
Super glue and coral adhesive
I would buy both of these before assembling the rockwork. Build and test the structure outside the aquarium, and let the joints set before moving it into place.
BRS Extra Thick Gel Super Glue — 10 Ounces
I would use this extra-thick gel to secure small rock contacts and attach coral frags. The 10-ounce bottle gives you plenty to work with while building the aquascape. Start with a stable structure rather than relying on glue to hold an unsupported pile of rock.
View the 10 oz Super Glue at BRS
Tunze Coral Gum Instant — 400 Grams
Choose the 400-gram version. This fast-setting, two-part coral adhesive is useful for securing small aquascaping pieces and coral mounts. Mix and use it according to the instructions, and check that each joint is secure before moving the structure.
View the 400 g Coral Gum at BRSOptional upgrades
The controller setup I would consider later
These are not purchases I would make right away. Once the tank is running, I like the idea of having more of its monitoring and power control together in ReefBeat.
Red Sea ReefControl Pro
An optional way to go deeper into the ReefBeat ecosystem. This package includes a pH and temperature probe and supports additional compatible sensors. It does not include an AC outlet strip; pair it with ReefControl Power if you want it to switch mains-powered equipment.
View ReefControl Pro at BRS
ReefControl Power 8 Deluxe with Control Panel
This adds eight controllable AC outlets and physical buttons for maintenance. For automatic heater control, you also need a compatible temperature-reading setup, such as the ReefControl Pro and its included probe. Power 8 can also use a separately purchased ReefSense Temperature Probe directly.
View Power 8 Deluxe at BRSKeep heater control in place. ReefControl Pro does not have general-purpose AC sockets. To control the titanium heater through Red Sea, you need the appropriate power hardware, a compatible temperature-reading setup, and correctly configured settings. The Inkbird remains my straightforward starting choice.
Plan the full cost
This is a premium 91-gallon build
BRS lists the aquarium package at $6,399 as of September 5, 2026. That is before the reservoir, heating equipment, RO/DI system, testing and maintenance supplies, salt, sand, rock, adhesives, and animals.
The package saves you from choosing most of the major equipment separately, but this is not an inexpensive build. Price the complete shopping list before buying, and keep the optional controllers and smaller rock accents separate from your starting essentials.
Compare before you decide
Would a peninsula suit your room better?
I personally prefer a peninsula when there is room to enjoy both long sides. The Peninsula 350 G3 has a smaller display but nearly the same major equipment. Compare the layouts, or explore all seven builds before deciding.
