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  • Eshopps Power Flow Hang-On Overflow Box
  • Eshopps Power Flow PF-300 hang-on overflow box for 30 to 75 gallon aquariums
  • Eshopps Power Flow PF-800 hang-on overflow box for 75 to 125 gallon aquariums
  • Eshopps Power Flow PF-1000 dual intake hang-on overflow box for 125 to 150 gallon aquariums
  • Eshopps Power Flow PF-1200 dual intake hang-on overflow box for 150 to 200 gallon aquariums
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  • Sku: 89014
  • Vendor: Eshopps

Eshopps Power Flow Hang-On Overflow Box

$129.98 USD
Shipping calculated at checkout.
Model: PF-300 (30 to 75 gal)

Product description

The Eshopps Power Flow is the classic way to run a sump on a tank that was never drilled. It hangs on the back rim, a U-tube siphon carries water over the glass into the external box, and gravity sends it down a 1 in bulkhead to the sump or refugium below. Four sizes cover everything from a 30 gallon reef to a 200 gallon display. Browse the rest of our sumps, skimmers and filtration, plus the return pumps and plumbing that complete the loop.

No drilling and no tank swap. Every Power Flow ships complete with the in-tank pre-filter box, the clear external box, U-tube siphon, foam cylinder, 1 in bulkhead and mounting hardware. Add a return pump and a sump and your heater, skimmer and media move out of the display.

How It Works

The black pre-filter box sits inside the tank and skims water from the surface, where oils and film collect. A foam cylinder inside it keeps fish and debris out of the siphon. The smoke-tinted U-tube arches over the rim into the clear external box, which hangs on the outside of the glass and drains through the bulkhead. Once the U-tube is primed it stays full as long as the return pump runs. If the pump stops, the tank level only drops to the pre-filter box, the siphon holds, and flow resumes on its own when the pump comes back.

Features on Every Model

Only 3 in of clearanceThe external box is 3 in deep on every model, so the tank can sit close to the wall.
Slim pre-filter boxThe in-tank box is noticeably slimmer than older overflow designs and takes little room from the display.
Smoke-tinted U-tubeTinted acrylic hides algae film and blends into the tank better than clear tube.
Recessed coverThe external box lid sits flush to cut splash and keep the drain quiet.
Quality acrylicClear external box and a black pre-filter box from a company that has built aquarium filtration for over two decades.
1 in bulkhead includedStandard 1 in bulkhead fittings connect to 1 in PVC or flexible drain line.
Complete kitFoam cylinder, nylon screws and wing nuts are in the box, ready to hang.
Fresh or saltWorks on any sump-based system: reef, fish-only marine or a large freshwater setup.

Choose Your Model

Select a model in the tab section below for its full spec sheet.

Spec PF-300 PF-800 PF-1000 PF-1200
Tank size 30 to 75 gal 75 to 125 gal 125 to 150 gal 150 to 200 gal
Max flow 300 GPH 800 GPH 1,000 GPH 1,200 GPH
Intake Single Single Dual Dual
U-tubes 1 1 2 2
1 in bulkheads 1 1 2 2
External box (W x D x H) 6 x 3 x 10 in 8 x 3 x 10 in 9 x 3 x 10 in 10 x 3 x 10 in
Item number 89014 89024 89034 89044

Detailed Model Specifications

Click a model below to view its full specification sheet.

PF-300 · Single intake · 300 GPH

The compact choice for 30 to 75 gallon tanks running a modest return pump. One U-tube and one 1 in drain handle up to 300 GPH, which suits most nano and mid-size reefs and smaller planted sump builds.

Specification Value
Item number 89014
Tank size 30 to 75 gal (up to 284 L)
Max flow rate 300 GPH (1,135 LPH)
Intake Single, one U-tube
Drain One 1 in bulkhead
External box 6 x 3 x 10 in (152 x 76 x 254 mm)
Clearance behind tank 3 in
Material Acrylic, clear external box, black pre-filter box
In the box Pre-filter box, external box, U-tube, foam cylinder, 1 in bulkhead, nylon screws and wing nuts

PF-800 · Single intake · 800 GPH

The step up for 75 to 125 gallon tanks. It keeps the single intake footprint but the wider box and drain path move up to 800 GPH, enough for a 4 foot reef with a mid-size return pump.

Specification Value
Item number 89024
Tank size 75 to 125 gal (up to 378 L)
Max flow rate 800 GPH (3,028 LPH)
Intake Single, one U-tube
Drain One 1 in bulkhead
External box 8 x 3 x 10 in (203 x 76 x 254 mm)
Clearance behind tank 3 in
Material Acrylic, clear external box, black pre-filter box
In the box Pre-filter box, external box, U-tube, foam cylinder, 1 in bulkhead, nylon screws and wing nuts

PF-1000 · Dual intake · 1,000 GPH

Built for 125 to 150 gallon tanks. Two U-tubes feed the box and two 1 in drains carry up to 1,000 GPH, and the second siphon adds a margin of safety if one tube ever loses prime.

Specification Value
Item number 89034
Tank size 125 to 150 gal (up to 567 L)
Max flow rate 1,000 GPH (3,785 LPH)
Intake Dual, two U-tubes
Drain Two 1 in bulkheads
External box 9 x 3 x 10 in (229 x 76 x 254 mm)
Clearance behind tank 3 in
Material Acrylic, clear external box, black pre-filter box
In the box Pre-filter box, external box, two U-tubes, two foam cylinders, two 1 in bulkheads, nylon screws and wing nuts

PF-1200 · Dual intake · 1,200 GPH

The largest Power Flow, sized for 150 to 200 gallon displays. Dual U-tubes and two 1 in drains move up to 1,200 GPH for high turnover on big reef and predator systems.

Specification Value
Item number 89044
Tank size 150 to 200 gal (up to 757 L)
Max flow rate 1,200 GPH (4,542 LPH)
Intake Dual, two U-tubes
Drain Two 1 in bulkheads
External box 10 x 3 x 10 in (254 x 76 x 254 mm)
Clearance behind tank 3 in
Material Acrylic, clear external box, black pre-filter box
In the box Pre-filter box, external box, two U-tubes, two foam cylinders, two 1 in bulkheads, nylon screws and wing nuts

Which Model Is Right for You?

PF-300 for 30 to 75 gallon tanks with a return pump moving up to 300 GPH at your sump-to-tank height.

PF-800 for 75 to 125 gallon tanks. Same single intake, wider box, up to 800 GPH.

PF-1000 for 125 to 150 gallon tanks. Dual U-tubes and two drains carry up to 1,000 GPH and give you a second siphon.

PF-1200 for 150 to 200 gallon tanks. Dual intake with up to 1,200 GPH for big displays and high turnover.

Size to the return pump, not just the tank. Look up the pump's flow at your actual head height, keep it under the overflow rating, and throttle the return with a valve if it runs close.

Installation Tips

Hang the external box on the back rim with the pre-filter box inside, then level it. Fill the U-tube completely with water, cover both ends and set it in place so no air is trapped at the top. Plumb the bulkhead to the sump with 1 in PVC or 1 in ID flexible tubing, start the return pump and watch the water line settle. Adjust the pre-filter box so the surface sits about halfway up its teeth. Check the U-tube for trapped air during routine maintenance and re-prime it if a bubble is growing.

Recommended Pairings

FAQ

Do I need to drill my tank?
No. The Power Flow hangs on the back rim and uses a siphon, so it works on standard glass or acrylic tanks with no holes.

What happens during a power outage?
The tank drains only down to the pre-filter box, then stops. The siphon stays primed and flow restarts when the return pump comes back. Leave room in the sump for that drain-down and for the water in the return line.

What size drain line do I need?
Each bulkhead is 1 in. Use 1 in PVC or 1 in ID flexible tubing to the sump. The PF-1000 and PF-1200 have two drains.

Can I use it on a freshwater tank?
Yes. Any sump-based system works, fresh or salt.

Can the siphon break?
Only if air collects at the top of the U-tube. Check it during water changes and re-prime if needed, and keep the foam cylinder clean so flow through the pre-filter stays steady.

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Eshopps Power Flow Hang-On Overflow Box

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