Filters

the age old subject of filtering my water is giving me strife i did not think it would be this hard but i have looked at canister filters but there so misleading

I have 2 canister filters running, a Fluval 103 on my 64ltr and a AquaManta EFX 200 on my 180ltr. I've found them to be a lot more straight forward than the internal ones (and a lot easier to maintain).

Which bits are you finding misleading?  Maybe we can help you come to terms with the subject.

I think the problem you have is to do with the published throughout rate being higher than the actual throughput rate;  Am I right?

If so, you should be aware that this is a problem with pumps in general, not just the pumps attached to an external canister filter;  Your 3000lph rated pumps will not pump 3000lph through your filter.

I shall try and explain.  The volume of water that a pump can shift is basically a function of the velocity of water exiting the pump and the diameter of the tube it is flowing through.  For all realistic measurements the diameter of the output is fixed, so we are reliant on the velocity of the water through the pump.  The problem is that there are lots of things that can affect this velocity;  But there are two big ones.

• The height of the output of the pump, your outlet tube into your tank, above the pump itself.  This is called the HEAD.  The bigger the distance the more it will affect the output.  The documentation that came with your pumps may also list a maximum head for the pump to operate (My filter specifies 1.4 metres)
• The presence of obstructions in the water path.  These include the filter media, the pipe, the plumbing (elbows T's and valves etc) and any foreign matter on the inside of these fittings.

Now the pump manufacturers have a big problem when publishing the flow-rate of a pump (or filter).  They have no idea on the position in which a pump may be used or on the contents of the filter or on the complexity and cleanliness of the plumbing it is attached to.  For this reason, any figure they publish is going to be, at best, a guess.