# Flow and Hydor Inline Heaters



## Greenview (5 Jul 2011)

I am thinking about getting a hydor inline heater. Does anyone know how much they affect flow rates? I am running an Eheim 2217 on a 180 litre tank, flow is ok (with the addition of a circulation pump) but I would not like flow to take much of a hit with an inline heater.
Thanks


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## rt964 (5 Jul 2011)

I've not used an in line heater, but am using 2 Rena Smartheaters in my tank whereby the heaters double as the uplift for my external filters, thus reducing the amount of pipework in the tank.  These have been running now for 8 months and I'm really pleased with them.  They hold the temp of the tank very well (28 degrees), and seem to have no detrimental effect on the flow rates.

Hope this helps !


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## madlan (6 Jul 2011)

I'm using one, doesn't seem to impact flow as much as I thought it would. What size is then return hose on the Eheim? I found reducing the diameter for the heater noticeably affects then flow rate.


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## idris (6 Jul 2011)

The pipe that runs through he centre of the 300W version is perfectly straight so, as long as the internal diameter is the same as your hoses, there should be no difference to flow. (I've got 22/16 hoses and it seems fine.)


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## Greenview (6 Jul 2011)

That is helpful.  If the diameter is the same as the return pipe (with no narrowing at the joins) then it makes sense that flow should be largely unaltered. I guess that the important thing is making sure that the heater does not produce bends or kinks in the return pipe because that would affect flow. I will need the 200w as it is the only one fitting the 12/16 pipe.
Thanks.


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## sanj (6 Jul 2011)

They should not impact flow that much. I use two on my aquarium and i dont the internal diameter is much less than the filter tubing.


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