How to Extract Water from Reef Tank without drillings of holes

29 March 2017


Reef tanks will  need fairly high water flow rate and an external pump sump is usually required so as to install a large water pump as well as other equipment such as chiller,  filter medias etc.  Large amount of water  will have to be extracted from the tanks.  The conventional way is to drill larger holes on either the top side of the back glass panel or the bottom of the tank.   This article will try to introduce another method.

What's Needed?

1.   1/2 piece of 4 feet x 2 feet perspex sheet available from any shop that sells lighting diffuser for the lighting fitting;

2.   2 numbers of 15" 20 mm diameter PVC tube

3.   2 numbers of straight joint for aquarium air distribution pipe

4.   Industrial Liquid Thinner

How to Construct?

 a.  Overflow box 

1.  Cut the perspex sheet to form a box of about 10" x 3"; make sure one of the back sheet of the box is long enough for a bend to be formed to hang over the edge of the water tank;

2.  Use heat gun or oven to soften the perspex of the longer back sheet with heat good enough to bend the perspex to form the hanger;

3.   Cut the front piece to form a row of grooves or small opening to allow overflow water to flow into the box;

4.   Assemble and join the 4 piece together using the industrial thinner.  Allow enough thinner to run to and fro at the joint so as to seal the joints properly;

b.  Over Flow Pipes

1.   Heat bend the 20 mm PVC pipe in the center enough to form a U-shape tube as shown in the picture;  The U tube should have a bend radius large enough for it to be placed over the hanger of the box;

2.   A flexible spring or PVC tube is necessary to ensure a smooth bend.  I used one piece of chest expander spring;

3.   Drill a hole large enough to insert the air tube straight joint at the top of PVC bend to form the air nipples

How It works?

When water is pumped into the tank,  the excess water will overflow into the overflow box.  It will be sucked up through the U-tube continuously.

But before any water can flow through the U tube,  the tube must be primed and fill the entire tube with water.

Water priming is make simple by plugging up the open end of the U tube and then suck the air out from the air nipple.  As soon as the water has filled up the U tube,  plug the air nipple and water will flow continuously and naturally.

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