These pre-filters are the best way to move water from an aquarium to a filtration system without expensive modifications. They quietly skim up to six times more water than units with tubes. Can be hard plumbed with standard PVC pipe. (Does not include lid.) Use of Aqua Lifter Pump is necessary to prevent trapped air from the siphon. Combine with Aqua Lifter Filter, a suction-style floss debris filter, to maximize efficiency and use of the Aqua Lifter Pump.
Please click on "More Information" for instructions and size information.
To place your overflow into operation:
Before using the overflow for the first time, it is important to decide where to position the unit. It is best to have the overflow as far away from the inflow as possible to reduce turbulence. It is also important to check the capacity of your sump as well as the flow rate of your return pump on your filtration system to prevent possible overflow. It will be necessary to add water to the system after it begins running. The amount of water that you will need to add will depend on the sump size and design.
Assemble the bulkhead fitting as shown in the diagram on your instructions. Insert the pre-filter screen into the bulkhead and place the pre-filter sponge over the screen. Insert the vent tube into the hole at the top of the pre filter screen. The "O-ring" can slide up or down to adjust the height of the vent tube once the unit is operational.
Connect the bulkhead to the hose going into your filtration system. You should use PVC tubing inserted into the bulkhead. The PVC can be run directly into the filter or can be attached to flexible line using fittings. The fewer bends in the line, the quieter the siphon will operate. To prevent leaking from where the PVC inserts into the bulkhead, you should use PVC cement to secure it into place (this, however, will make the connection permanent).
Place the unit on the edge of your tank and allow the water to fill the front chamber. Adjust the lower adjustment screws so that the unit is parallel to the back of the tank.
Adjust the height of the unit with the two top adjustment screws so the water level is about 1/4" above the edge of the front chamber. Make sure that the overflow is level with the water surface, not necessarily the tank, as some tanks may not be perfectly level. If you have small fish, adjust the fish screen so that the fish cannot enter the overflow.
Using a container of water from your aquarium, fill the narrow chamber in the back of the overflow to the top. To start and maintain the siphon overflow, draw the air out through the nipple on top of the overflow by one of the following methods: a Venturi powerhead, plugging the air nipple, or gravity siphon.
When you initially start the siphon overflow, it will drain water from your aquarium down to the level of the front edge of the overflow box. The sump part of the filter should begin to fill with water. It may be necessary to add water to the sump if the return pump is not completely submerged. Make sure that the return hose is firmly attached to the return pump before plugging in the pump.
Plug in the return pump. Keep an eye on the water level in the tank to make sure the overflow starts its siphon. Water should start draining down the overflow. At this point, direct your attention to the sump to make sure the return pump is still completely submerged, or that the sump is not overflowing. It may be necessary to add or remove water from the sump at this point. Continue to monitor both the tank and the sump for a few minutes to ensure that the system is working consistently.
The water level in the aquarium can be adjusted by using the two top adjustment screws on the overflow. This is usually necessary once the overflow has been operational for a few minutes. By lowering the water level in the aquarium, you will raise the level in the sump and possibly overflow it. By raising the water level in the aquarium, you will lower the water level in the sump and the return pump could possibly burn out if not completely submerged. Add or remove water as needed.
At certain flow rates, there will be a flushing noise coming from the overflow. This noise is caused by air trying to escape back up through the bulkhead while the water is going down. The enclosed vent tube will help reduce the level of noise. Place the tube through the small hole in the pre-filter screen and adjust it up or down until you find the point where the noise is reduced the most. Slide the small "O-ring" down until it reaches the pre-filter screen, securing the position of the vent tube.
Your overflow will then be in operation.
Item#
Area
Behind
Tank
Bulkhead
Size
# of
Bulkheads
# of
Sponges
Gallons
Per
Hour
790065
4-1/2"
3/4"
1
1
300
790078
5"
1"
1
1
600
790091
5"
1"
1
1
800
790104
5"
1"
2
2
1200
790117
6"
1-1/2"
1
none
1600
Testimonial By:
Testimonial:
Christopher S North Little Rock, AR
Works well. I replaced the diaphragms after about 15 months of use and you will know when to replace them because the overflow chamber will have quite a bit of air at the top of it and flow will be greatly reduced, risking an overflow of your tank. I caught mine in time. My only complaint is that the screw (B) that holds the two pump chambers together should be included in the kit. After such a long time running with water going through the pump, the screw head was so eroded that I had to break the two pieces apart. Luckily I was able to find a screw that would fit for the new pieces. Overall I am satisfied with the product and have ordered two more kits to have on hand.
Nice product - highly recommend. Spend the few extra bucks to get aqua lift pump, had to come and order it as small bubbles were created in the free fall of water initial inside and traped in inner chamber. Watched this closely as recommended and discovered this - the aqua lift should fix the problem. I got the 800 gph unit. Wish there was a lid ontop like shown on youtube instructional video though.
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Please note: Return of electrical equipment to Foster & Smith Aquatics for exchange or refund is limited to 60 days from the date of purchase. Beyond 60 days, please contact the manufacturer for repair or replacement as covered by the manufacturer's warranty.
 "Continuous Siphon Overflow")
These pre-filters are the best way to move water from an aquarium to a filtration system without expensive modifications. They quietly skim up to six times more water than units with tubes. Can be hard plumbed with standard PVC pipe. (Does not include lid.) Use of Aqua Lifter Pump is necessary to prevent trapped air from the siphon. Combine with Aqua Lifter Filter, a suction-style floss debris filter, to maximize efficiency and use of the Aqua Lifter Pump.
