Ordered a new canister filter.

[Wyomingite]

There is one other factor to bear in mind here. The potential flow rate of the intake side of any filter must be at least as great as return flow rate for that filter. If the return rate is higher, the filter will soon empty itself.

Many years ago in a long defunct fish chat I was taught about pumps by a gent who spent his life working with the really big ones. Hge pums like those in electric power plants or other extremely high flow applications. He explained that flow should always be controlled from the output side, never from the intake side. If the output side of a pump is above the maximum head, the pump will run fine for a long time without any water coming out of the output side. On the other hand if the intake side is impeded and the output side maintains the same output flow, the pump will destroy itself in short order.

To clarify, the flow of the intake (or suction) must be equal to or greater than the outlet (or discharge) on any pump, powerhead, filter or any other equipment which operates by moving water with an impeller. I think that's what TTA was saying, but he kinda lost me.

The above is mostly true with centrifugal pumps, or pumps with an impeller that rotates to move water, which work by increasing the water's velocity and pressure and directing the water towards the pump discharge due to the angle of the impeller blades. If the discharge of a centrifugal pump is completely blocked in, it can be kept a long time without damaging the pump. However, since the water in the pump casing (which is the part of the pump in which the impeller is housed) is only replaced by very small volumes, the rotation of the impeller will eventually heat the water up due to friction. The water will reach the vaporization point eventually. When the water becomes vapor (steam) it is no longer pumped, reducing how much water is circulated or rotated until all the water is steam, and the pump will overheat and be damaged. How fast it reaches this point will depend on the volume of the casing, the material of the pump parts, and the speed of the impeller (rpms). This is going to take a long time in pumps, unless you also loose the suction (or supply) of the pump, in which it can happen within minutes. I'm mainly bringing it up to say you can't block in the discharge and then forget about it and leave it indefinitely. At some point it will be damaged.

The above does not apply to positive displacement pumps at all, but I'm not aware of any positive displacement pumps used by aquarists. However, a significant number of air compressors are positive displacement. Anyways, the discharge of a positive displacement pump normally directs the pressure from the pump housing down the discharge line with the fluid. If the discharge is blocked in, the fluid isn't directed anywhere and pressure builds up in the casing. Eventually this pressure build up will exceed the maximum the pump or compressor can withstand and overpressure the pump, damaging the pump or compressor. This happens a lot quicker than blocking in the discharge of a centrifugal pump.

WYite

 

[super tetras]

im trying a under gravel filter next then possibly a canister filter