Active Aqua Grow Flow 5 gal System – Expansion Kit

The Active Aqua Grow Flow 5 gal System Expansion Kit adds 12 additional 5-gallon growing modules to an existing Grow Flow ebb & flow setup. Each kit plugs into the same controller unit and 55-gallon reservoir already running your base system, letting a single controller manage up to 24 sites total — without adding a second pump system or controller.

Active Aqua Grow Flow 5 gal System Expansion Kit Specifications

All specifications are drawn directly from manufacturer documentation for this expansion kit. The kit is designed to integrate with the Grow Flow complete system using the existing controller and reservoir.

Specification	Value
System Type	Ebb & Flow (Flood & Drain)
Growing Modules Included	12 × 5-gallon double-bucket modules
Module Capacity (media)	13 L of clay pebbles per module
Tubing Size	3/4 inch
Pump Voltage	120V (uses existing system pumps)
Max Sites Per Controller	24 × 5-gallon modules
Expansion Increment	12 sites per expansion kit
Weight	15 lb (kit, unboxed)
Warranty	3 years
Brand	Active Aqua / Hydrofarm

Why Choose the Active Aqua Grow Flow Expansion Kit

The Grow Flow Expansion Kit is purpose-built for growers who are already running the Grow Flow complete system and want to scale their canopy without adding a separate controller, reservoir, or pump line. Here is what makes it a practical choice:

• Doubles your plant count from one controller. A single 5-gallon Grow Flow controller unit can manage up to 24 growing modules. One expansion kit brings you from the base 12 sites to the full 24-site maximum, so you use every bit of controller capacity before adding hardware.
• Double-bucket design simplifies transplanting and harvest. Each growing module is built as an outer bucket with a fitted inner bucket. When it is time to move or harvest a plant, you lift the inner bucket — roots, media, and all — without disturbing adjacent plants or disconnecting tubing.
• Fail-safe overflow protection carries over to expansion modules. The existing controller’s adjustable float ladder and emergency shut-off valve protect the entire system, including any expansion modules you add. If the float valve fails, the LED indicator on the control panel lights up and the shut-off valve stops the pumps before water reaches the floor.
• Includes all fittings and tubing. The kit ships with the 3/4-inch tubing and fittings needed to connect the new modules to your existing manifold. No separate plumbing run to a hardware store before you can set up.
• Three-year warranty on all components. The same warranty that covers the complete system applies to expansion kit components, giving you consistent coverage across the full installation.

Best Uses for the Active Aqua Grow Flow Expansion Kit

This kit makes the most sense in specific grow room scenarios. The following situations are where growers consistently get the most value from adding a second set of 12 modules:

• Filling unused controller capacity. If you bought the Grow Flow complete 12-site system and your controller has been running at half its supported load, this kit lets you use the other 12 slots without buying a second controller or reservoir. You already own the infrastructure — the expansion kit puts it to work.
• Sequential harvest cycles. Running a perpetual harvest in a single room is easier when you can stage plants at different ages across 24 sites rather than 12. Growers using the expansion kit often stagger planting dates across the two banks of 12 so harvests happen on a rolling basis rather than all at once.
• Medium-to-large indoor grows using clay pebbles as media. The 5-gallon modules, each holding 13 liters of expanded clay, are well-suited to crops that benefit from good aeration at the root zone and a structured flood-and-drain cycle. Tomatoes, peppers, cucumbers, and larger cannabis plants commonly run in setups like this.
• Commercial hobby and small commercial operations. A full 24-site Grow Flow system — base kit plus one expansion — provides enough canopy for a serious hobby grow or a small-scale commercial operation without the complexity of a reservoir farm or NFT channel layout.
• Growers who want to add capacity without changing media or nutrient programs. Because the expansion modules are identical to the base kit modules, your media, watering schedule, and nutrient cycle stay the same. There is no separate calibration pass for the new modules. For a related upgrade that improves water quality before it enters the system, an inline water filter such as the Dilution Solutions 1-1/2 in. filter with 200-mesh screen is worth pairing with any expansion.

Grow Flow Expansion Kit vs Similar Products

Expansion kits for ebb & flow systems vary considerably in how they integrate with their parent systems. The Grow Flow Expansion Kit is designed as a true plug-in addition: the controller, reservoir, and pumps from your existing 12-site system handle the new modules without modification. Some competing expansion systems require a second pump controller or a parallel reservoir to support additional sites, which increases both the equipment cost and the number of failure points in the system.

The double-bucket module design also distinguishes the Grow Flow from simpler single-bucket ebb & flow setups. Single-bucket systems require you to disconnect the fitting and deal with the wet media directly when moving or harvesting a plant. The inner/outer bucket arrangement lets you lift a plant out cleanly. If you are considering a DIY expansion using individual components — separate buckets, manifold fittings, and bulk tubing — the expansion kit generally comes out cheaper once you account for fittings and the time involved in sourcing and assembling parts. It also ensures the tubing diameter and fitting specs match what is already running in your system.

If you need to monitor dissolved oxygen or run a dedicated aeration line alongside your ebb & flow setup, the Active Aqua air pump (1 to 8 outlets) pairs naturally with Grow Flow bucket setups to keep the root zone oxygenated between flood cycles.

Compatibility

The Active Aqua Grow Flow 5 gal Expansion Kit is compatible with the Active Aqua Grow Flow 5-gallon Complete System. The controller unit from that system can support up to 24 of these 5-gallon modules, so one expansion kit brings you to the full controller limit. The kit uses the same 3/4-inch tubing and fittings as the complete system, so no adapter pieces are needed.

The system pumps operate on 120V standard household current, which is the same voltage the two 250 GPH pumps in the complete system use. No new electrical work is required to add the expansion modules — the existing pumps, timer, and controller handle the increased site count within the rated capacity.

The 5-gallon modules accept 13 liters of expanded clay pebbles (hydroton or equivalent) as growing media. The modules are not designed for rockwool slabs or loose coco coir without a liner, as the inner bucket is an open-mesh structure sized for coarse media. If you are measuring the water quality going into your system, the Hydro-Logic Micro 75 GPD RO system is a compact option for pre-treating source water before it enters the reservoir.

This kit does not include a controller module, reservoir, or pumps. Those components must come from a Grow Flow Complete System purchase. If you are building a Grow Flow setup from scratch and want to start at 24 sites, you would purchase the complete system and this expansion kit together.

Usage Guidelines

The Grow Flow system runs on a timed flood-and-drain cycle. You set the fill duration and the drain interval on the controller unit, and the pumps handle the rest. Here is how to think about each setting when adding expansion modules:

• Fill duration: With more modules connected, the volume of nutrient solution flooding the system increases. Check that your fill duration is long enough to bring all 24 buckets to the correct flood level before the drain cycle begins. You may need to extend fill time slightly compared to what you used with 12 sites.
• Drain interval: Ebb & flow cycles are typically set based on the crop, media, and climate. Clay pebbles drain quickly and do not retain much moisture between floods, so most growers run 4–8 flood cycles per day under lights. Adjust based on the plant stage — seedlings and early veg generally need fewer floods than large plants in peak flower.
• Float valve and overflow check: After adding the new modules and running a test flood, confirm that the float valve in the controller module stops the fill at the correct level. Also verify that the LED overflow indicator on the control panel stays off during normal operation. A lit indicator means the float valve did not trip correctly and the emergency shut-off activated.
• Nutrient solution volume: The 55-gallon distribution reservoir in the complete system is sized to handle 24 sites. At full capacity, you will use the reservoir volume more quickly between refills. Top up EC and pH after each reservoir refill rather than waiting for the next scheduled maintenance cycle.

How to Install the Grow Flow Expansion Kit

These steps assume you already have a functioning Grow Flow 5-gallon Complete System with the controller module, 55-gallon reservoir, and two 250 GPH pumps installed and tested.

1. Drain and power down the existing system. Turn off the controller and pumps before making any plumbing connections. Drain the system down to the reservoir so the tubing and manifold are empty and at atmospheric pressure.
2. Unpack and inspect the expansion kit. Verify you have 12 outer buckets, 12 inner buckets, the required 3/4-inch fittings, and the tubing lengths. Check all buckets for cracks or warped fittings before assembling.
3. Position the new module locations. Lay out the 12 new double-bucket modules in your grow room. The modules should be on a level surface and arranged so the tubing run from the manifold to each bucket stays as short and direct as practical.
4. Connect the tubing to the existing manifold. Use the included 3/4-inch fittings to tap the new modules into the distribution manifold from your existing system. Each module gets an inlet line from the manifold and a drain line back to the reservoir. Tighten all fittings hand-firm; check the existing modules to match the connection style already in use.
5. Fill each inner bucket with clay pebbles. Add up to 13 liters of pre-rinsed expanded clay per module. Rinse clay pebbles thoroughly before use to remove dust and lower any initial pH spike from the media.
6. Run a water-only test flood. Restore power to the system and trigger a manual flood cycle using plain, pH-adjusted water (no nutrients). Watch each of the 12 new modules to confirm the flood reaches the intended level and drains fully within the cycle window. Check all new fitting connections for drips.
7. Check the float valve and LED indicator. After a successful test flood, confirm the LED overflow indicator on the controller panel stays off. If it lights up, the float valve did not operate correctly — troubleshoot before introducing plants or nutrients.
8. Adjust fill duration if needed. If the new modules at the far end of the manifold fill more slowly than the original 12, extend the fill time on the controller by small increments until the flood level is consistent across all 24 sites.
9. Introduce plants and begin normal nutrient cycles. Once the test flood passes without leaks and the float valve operates correctly, transfer plants into the inner buckets and resume your standard flood-and-drain program.

Sources & Further Reading