When I first filled the tank and ran the sump return pump to test for leaks and to test the sump, the noise from the drain pipe was too loud for our (me and the wife) sanity. Tweaking the ball valve at the drain pipe didn’t help much. It reduced some sound but there were various side effects:

• The water level fluctuated, resulting in intermittent draining noises.
• Small bubbles coming out of the bottom of the drain pipe. Not a good thing for maintaining CO2 levels in the water.
• Large pockets of air would be blasted out of the bottom of the drain pipe occasionally, causing lots of splashing and occasional noise.

So I started looking up solutions on the net.

The findings:

• Bean Animal’s Silent & Fail-Safe Aquarium Overflow System
• Maggie Muffler
• Durso Standpipe
• Stockman Standpipe
• Hofer Gurgle Buster

Except for the Maggie Muffler, all require DIY. The Bean Animal’s System requires extensive modifications and was simply not feasible in terms of space, location, and work/tools required.

The Maggie Muffler is a commercial product that is fairly affordable and easy to install, but I could not find any shops selling this in Singapore or any online seller that ships to Singapore. The original manufacturer did not respond to my emails.

The Durso Standpipe is easy to make, but I do not have enough space inside the overflow box to fit one.

The Stockman Standpipe is a little harder to make than the Durso but doable.

The Hofer Gurgle Buster (HGB) is a variation of the Stockman. The instructions are pretty much the same. The main difference is the way the air pipe is installed and utilised.

The final candidate was the HGB as most sites say it’s quieter than the Stockman. Here are the photos of the build:

I won’t repeat the detailed parts and instructions here. Just follow the link above and you should be able to figure out the differences from my photos above. You will need a drill, a saw and a half-round file.

Make sure you drill enough holes to match the inner cross-section of the drain pipe to ensure you get the same flow rate. For simplicity, if the inner diameter is X, then you need to drill 4 holes with half X diameter. For example, if the inner diameter of the pipe is 25mm, then drill 4 holes with 12.5mm diameter. Slightly larger is fine. In my case, instead of round holes, I made slots instead. If you don’t have a big enough drill bit, just calculate the cross-section of the hole your biggest drill bit will make and figure out how many of these holes you need so that their total cross-section exceeds the inner cross-section of your drain pipe.

You need the half-round file to file down the inside of the reducer (the piece that looks like a funnel) so that it can slide up and down the pipe. It should be able to slide easily without too much effort but stay in place once adjusted.

I secured 2 zip-ties to the black hose, 1 inside the end cap and 1 outside, to prevent the black hose from being pulled up or pushed down too far.

The results? Better than I expected. The tank is now almost completely silent. So silent that if you didn’t listen for it, you wouldn’t even notice any noise from the tank filtration. The water drainage is much more stable. I’ve managed to tweak the ball valve so that no bubbles are exiting the bottom of the drain pipe at all.

Parts bought from Hai Cheong Plastics Pte. Ltd. Just walk through to the office at the back and tell the office workers you want to buy some parts. Friendly and allows walk-in small purchases and (I think) charges at wholesale prices (or at least, lower than the retail prices at small hardware shops). Some of the older worker uncles in front may be a little grouchy, but you can ignore them. I’m not sure whether they will sell short lengths of PVC pipes as I reused my drain pipe. I recommend that you bring your drain pipe if possible. If not, measure the external and internal diameters of your pipe before going. PVC manufacturers use the internal diameter to categorise parts, and Hai Cheong supplies the JIS standard PVC pipes (check your PVC piping, the standard is usually printed somewhere on them).

Hai Cheong Plastics Pte Ltd
11 Kallang Place
#01-11
Singapore 339155
Phone: +65 6294 4406

Now the only noise I hear from the tank is the two PC cooling fans. The next step, replace those fans with quieter ones.