Sunsun Flow Rate Adjustment?

**tackful** · 08-03-2012, 10:14 PM

Is it possible to decrease the flow rate on a Sunsun 265 gph canister filter without making it noisy? I used to have a Magnum 250 HOT filter, but it caused too much disturbance and CO2 loss, so I had to slow it way down, I tried several methods, but all of them caused too much noise.
I believe Sunsun also has a 160 gph model, which would be perfect for my tank, but I've looked everywhere for it without success. Does anyone have a source to suggest? Thanks.

**CWO4GUNNER** · 08-04-2012, 3:13 PM

The easiest way is to restrict the small surface area of the 1st basket (bottom basket) by placing in several stacked polishing pads or stuffing it with Poly-batten. You can also shorten the impeller blades by cutting them down 25% evenly. You can also install a bypass hose that between your intake and out-flow hoses as close to the canister as possible with a ball-valve in the center. The ball valve will regulate how much water is redirected back to the canister before water has a chance renter the tank, anywhere from a small trickle to full force depending on the ball-valve position. The last option is the best but requites more DIY initiative. Hope that helps...

**tackful** · 08-04-2012, 10:01 PM

I like the bypass option; that's very ingenious. Thanks.

**CWO4GUNNER** · 08-06-2012, 1:01 PM

Too kind... Some might say you could also simply install the ball valve inline (series) on either hose instead of my more complicated option of using T-fittings to place the ball valve between hoses (parallel) as I suggested. But my method will allow the pump motor to work normally without excessive load and simply polish the water that is being recirculated back giving additional filtering rather then simply restricting the line. Also my method will not only drop volume but also pressure in the outflow line because the negative and positive pressure between the lines is being equalized. Restricting the line drops volume but not pressure.

**tackful** · 08-06-2012, 7:55 PM

Yes, that does make sense, and it really doesn't seem that difficult. Just two "T" fittings and one ball valve. One question, though: how can we be sure that water flows through the valve in the desired direction? I would think this is dependent upon outflow pressure being the greater of the two, rather than pressure being equalized.

**CWO4GUNNER** · 08-08-2012, 3:35 PM

Well we already know that the pump is capable of pumping against the max head pressure for your setup, so after your modification the pump will still be pumping and displacing water at the same rate but the water will take the path of least resistance dependent upon the ball valve position. But whether the ball valve is fully closed, fully open, or somewhere in between, the max head pressure will not exceed its original set up amount except lower on the return side as water has to return to fill what the pump is flowing out the outflow dictated by the ball valve position. Pretty basic hydraulic theory really.

**tolawdjk** · 08-08-2012, 4:15 PM

To decrease the surface aggetation on my Sun Sun I just positioned the outflow holes so they were pointed to the tank back and down. Depending on the "down angle" I could get zero surface disruption to a slight rise.

**tackful** · 08-08-2012, 8:51 PM

Originally Posted by tolawdjk

To decrease the surface aggetation on my Sun Sun I just positioned the outflow holes so they were pointed to the tank back and down. Depending on the "down angle" I could get zero surface disruption to a slight rise.

Funny you should mention that. The filter arrived yesterday and I just finished installing it with the spraybar angled downwards as you suggest. I actually prefer this to the funnel type of outflow on my Magnum, which just blew everything around in the tank. There does seem to be a flow rate lever and twin ball valves at the inlet/outlet connection, but it doesn't seem as though I will need to use it. Whether it's the gentle dispersion of the spray bar or all the media I have in the canister, the Sunsun at full blast is not overpowering my planted tank at all.

**CWO4GUNNER** · 08-10-2012, 4:36 PM

Yes the Sunsun for all its economics is a far weaker filter in throughput and filtration effectiveness then the Magnum. I have both and to compare the two is like night and day, since the Sunsun barely flows water out compared to the Magnums high pump rate you should have no problems with the Sunsun disrupting anything.