Install water pump and test run

It’s time to install the water pump, do the wiring, fill water into the tanks and do a test run to check for the aquaponics system operation.

Using tap water, filling this 1000 liters tank took around 1 hour plus
This 2000L/hour submersible water pump is connected using PVC pipe to the rest of the system.
Using leftover plywood and planks, I made this sort of electrical box, which is then covered with tarpaulin, to house the extension plug from rain.
Here’s the finished box, where I put also the timer for external lighting.
Water pump is installed inside the sump tank. Got some leaking at the connection, I used PVC male socket, layered with 15mm hose (orange color) and then clamped with the 1-inch connector hose (transparent).
Filling up the 3 DWCs. The water flow quite low here, even with the valve to the fish tank is closed. Maybe because of the leaking at the connection inside sump tank. It took a lot longer to fill the DWC to the desired deep (1 feet), so I just fill up to the stand pipe height (around 4-5 inch).
As the water inside the DWC rises it became apparent that it got some leaking. However, with the current design of the DWC, it’s quite hard to detect where the leaking is, because I can’t lift up the DWC and check underneath.
Among all of the causes of leaking, I think this is my biggest mistake. Silicon sealant doesn’t work on pipe connection, and it is harder to do adjustment because I need to wait for the silicon to dry. When the water inside tank rises even for a few inches, it creates water pressure which silicon sealant cannot contain.
So I disassembled two of the DWC and try to work with only one in fixing the leaking issue.

Currently I hit a roadblock in building this aquaponics set. First is the leaking issue. It’s like everywhere is leaking, due to my usage of silicon sealant at the pipe connection. I decided to use sealant because I couldn’t find suitable pipe fittings for the tanks:

  • there are no uniseal sold here, even the regular rubber seal only have size up to 1.5 inch.
  • bulkhead fitting is quite expensive, and I only can find it sold online
  • 2-inch PVC tank connector doesn’t fit with 2-inch UPVC

Another issue is the low water flow from the water pump. This probably cause by the leaking at the sump tank connection, and also maybe because of the head height (2 meters). Water from the pump is split to the fish tank and DWC. Pipe into the fish tank is around 90 cm height, so assuming the flow rate decrease is linear, at 0.9 meter, the water flow is theoretically 1100L/hour. Adding the split line to the DWC and all the elbows turn that add friction to the water flow, the value might be much lower. For now, I let the valve at the DWC slightly open and at the fish tank fully open, but only little flow is coming out to the fish tank.

Plumbing the aquaponics units together

Revised plan.

I changed the arrangement of the tanks, and solid filter drain outlet now connected directly to the sump tank, to reuse the water while filtering out the solid waste.

Overview of the arrangement of fish tank, then to solid filter, and then bio filter, and lastly to the sump tank in the ground.
Inside the sump tank. All water returns here, except for pipe from pump, which distributes back the water to the fish tank and DWC, and the overflow pipe (at 6 o’clock)
Pipe into the fish tank, with ball valve to control the water flow. It’s about 3 ft. (90 cm) in height.
Pipes to the DWC with ball valve each, and about 16 in. (40 cm) height.
And these are the stand pipes from the DWC back to the sump tank.

All pipe connections are glued, and the connection to the tanks are sealed using silicon sealant. This is far from complete, as I still need to do test run & check for any leaking. Also need to make sure correct water flow from the sump to the fish tank and DWC.