[DNK]

About having extra filtering due to overstocking etc, have any of you actually tested the LPH of your filters?

Did mine recently, it's a Tetratec EX1200 (Marineland C-360 your side of the pond.) It's rated at 1200LPH but was actually only pushing through 600LPH. The media wasn't cleaned out but it's never full of crud anyway. I expected it to be a bit less than the rated figure but not 50% of it. The tank's been running fine since it's been set up so not too miffed but still....

 

[Britnick]

Although not totally surprised that you are getting these results, a 50% decrease would appear a little harsh.

As I understand it, the figures manufacturers quote are for filters with no media and with no hoses attached. So the filter doesn’t have to push a head of water (which takes some doing and will greatly affect output).

Wonder what other filters actually do… worth a good discussion I think :thumb:

 

[Toby_H]

I've toyed with several brands of filters and have found consistently that canisters actually operate at 50% and HOBs at just under 75%...

In both this is with mature media that was not by any means clogged... which is what I expect most of us to be working with...

I experimented mostly with canisters as flow rate became very important to me when I started using them to push water through UV lights…

 

[Bastables]

Testing done by a member of planted tank forum:

"Dispelling a myth.

Compelled by the many contradictions on flow rates and overall lack of information available, I purchased a new Eheim 2215 and a 2217 for testing purposes.My primary intention was to test for flow rates on new filters,with and without filter media,and to see if these filters would actually produce their advertised flow rates.I also conducted tests with and without the included spray bars.Upon close examination of the filters I noticed that the impeller assemblies were identical on both of the filters except for the 2217 having a 6 blade impeller,and the 2215 having 3 blades.I then decided to test the 2215 using the 2217 impeller to overdrive it and to consequently boost the flow rate.I likewise ran a test on the 2217 using the 2215 impeller to under drive it to reduce the flow rate.As I expected,I was able to boost the flow rate significantly on the 2215 using the 2217's impeller assembly,and predictably got a corresponding reduction of the flow rate on the 2217 using the 2215's impeller.

The tests were conducted with the filters sitting on the floor with a 50 inch water height to simulate actual conditions,and tests were also conducted with the filters elevated on a 30 inch platform after I failed to match the advertised flow rates.Results were obtained by using a stop watch to measure the seconds to pump 5 gallons,and then dividing the seconds by 3600 and multiplying this figure by 5.The numbers were rounded out to the nearest 1/2 gallon. Surprisingly,elevating the filters did not improve the performance as I expected,and there was no measurable gain.However,my biggest surprise was that the output on both of the filters was the SAME,with the included Eheim filter media,and with empty canisters.

Advertised flow rates are 164 gph (620l/h) for the 2215,and 264 gph (1000 L/h) 2217.

Results

{2215} ---------------w/2217 impeller

141.5 gph (535.6 l/h) open tube ---171.5 (649) open tube

136 gph (514.8 l/h) w/spray bar -----152.5 (577.2) w/spray bar

------------------------------------------------------------------

{2217} --------------------w/2215 impeller

229 gph (866.8 l/h) open tube--------- 195.5 gph (738.1 l/h) open tube

202 gph (764.6 l/h) w/spray bar ---------171 gph (647.3 L/h) w/spray bar"

http://www.plantedtank.net/forums/equip ... mance.html

I added the L/h for comparison buy using google conversion.

The diffrence in preformance is i think due to higher del head on the eheim motors. 2215 is 1.8 2217 is 2.3 the tetra 1200 is 1.8.

these two eheims are pushing actul preformance of 82% to 76% or rated max l/h