Does Live Rock need light?

[Juck]

I have an old cannister filter lying around and was toying with the idea of filling it with LR (only, no marco) and using it as extra filtration for my 10g nano.

The cannister is a good size and I reckon I can get about 10-15lbs of LR in there, but there would be no light. Will the LR still be an efficient biological filter in total darkness?

The cannister itself is transparent,, if a small amount of light is needed I could hang one of those Power Compact work lights (13w 6700k) that cost $9.99 at Walmart next to it.

Thanks in advance

 

[Len]

A good number of organisms that inhabit live rock such as coralline require light for photosynethesis, but if you're goal is to use LR primarily as a biological filter, it doesn't need light.

It might not be the best idea to run LR inside a canister filter, however. I can imagine a lot of particulates from the LR clogging the canisiter motor.

 

[Juck]

Thanks Len,,, the LR is quite old, was in a FOWLR tank for years,,, not much coralline left on them,, I assume because I never really dosed the tank with anything.

I think I'll give it a whirl anyway,,, the pump is rated at 310gph but there'll be nearly 5 feet of head to deal with,,I reckon I'll be lucky to get 100gph through the tank.

I'm not big on mechanical filtration but I could jerry-rig something if particles become a problem,, and I have a spare motor somewhere.

Thanks again

 

[Anonymous]

Juck, on a canister filter you don't have to deal with head from vertical distance. There are head pressures associated with pipe friction, elbows in the pipe, etc. that WILL affect your pump performance. However, whether you setup the canister at the same level as or below the tank you will get virtually the same output.

 

[Juck]

Hey Matt, thanks for your reply.

>>on a canister filter you don't have to deal
>>with head from vertical distance

C'mon,,, you're saying the same pump can move the same amount of water at 1 foot of head as it can at 5 foot? or 50 foot? Not in this universe!

Seriously though,, did I doze off in high school physics and miss something? The tank is on a 5 foot tall stand and my xenia aren't up to 300+gph of turbulence.

 

[Anonymous]

Juck,
You can try it out if you like. Fill up your canister with saltwater so that both the input and output tubing are filled with water. The water level will fill right up to the main tank water level, even when the pump is not on. Turn the pump on, and it only has to lift the water above the elbow in the piping (around 2" or so in most cases).

If it's a sealed container like most canister filters, then the pump behaves as if it's under the same amount of water pressure that correlates to the distance it sits below the tank. Whether the pump is 10', or 100', below the water level in the main tank, it will have the same amount of head pressure that is caused by vertical distance. Keep in mind that because the vinyl tubing and PVC of the return plumbing have a bit of friction with water, there is a bit more head pressure loss caused by friction.

The situation changes completely when the pump is sitting in a sump. The pump is only under pressure from the much lower water level of the sump. In this case the pump puts out less GPH due to head pressure.

Hope this helps, Matt

 

[Anonymous]

To answer your direct question...
If two idenical canister filters are placed 1' and 50' below a tank, the second will pump out much less water. However, if you placed the second canister filter at the same elevation, yet 50' feet away, *it will pump virtually the same amount as if it were 50' below the tank.* This is because the loss of GPH is due to friction caused by the tubing, not by the vertical distance between the tank and filter. I hope this is clear.