Midas Posted August 2, 2002 Report Share Posted August 2, 2002 What flow rate are people getting out of their canister filters? Has anyone else ever measured the flow rate? I have been having a few flow issues with my fluval 404 lately. After getting a new head unit for it it still only does about 600 l/hr (up from 400 l/hr before the head was replaced) when it rated at 1300 l/hr. Do the MSF series get closer to the rated flow rate or is the rated flow based on the filter being empty or something? Does anyone actually get the the flow rate out of their canister filters that they are rated to do? Quote Link to comment Share on other sites More sharing options...
cees Posted August 3, 2002 Report Share Posted August 3, 2002 Do the MSF series get closer to the rated flow rate or is the rated flow based on the filter being empty or something? Does anyone actually get the the flow rate out of their canister filters that they are rated to do? Quote Link to comment Share on other sites More sharing options...
Ira Posted August 3, 2002 Report Share Posted August 3, 2002 Just tested mine. Got 384 liters per hour. That was by holding the outlet about the same height it is when running normally and pouring into a bucket for 1 minute then scooping the water out with a 1 L measuring cup. The filter in this case only has to pump the water a height of less than 2 inches. Hmmm...One of my other 404s could probably use a clean, I might go and try testing it before cleaning, empty and with the media but after cleaning. Quote Link to comment Share on other sites More sharing options...
cees Posted August 3, 2002 Report Share Posted August 3, 2002 .. holding the outlet about the same height it is when running normally .....The filter in this case only has to pump the water a height of less than 2 inches. Confusing , define normally. (I intepret that as tank height What's the diameter of you outlet tubing ??Is that restricting ? Aaahhh found the link I was looking for http://www.hagen.com/uk/aquatic/manuals/fluve08.cfm My guess, you get 384 L /hour, you are pumping up about 1.5 m which is about tank high on a normal stand (assuming your is a fluval 403 or 404) Quote Link to comment Share on other sites More sharing options...
Ira Posted August 3, 2002 Report Share Posted August 3, 2002 The only height that matters for the pump is how high the outlet is above the surface of the water. The distance to go from the inlet down to the cannister and back up to the level of the water doesn't matter except for the resistance of the hoses. Basically it's like siphoning the water down and through the cannister and back up. So the pump only has to lift the water an extra inch or two, less if the outlet is at the surface of the water or below. Gimme a few minutes I'll be finished testing the output of the other filter and will post the results. Quote Link to comment Share on other sites More sharing options...
Ira Posted August 3, 2002 Report Share Posted August 3, 2002 Just to be thorough, the filter(both fluval 404s) I previously mentioned was cleaned 1 week ago. Inside it 1 tray of big ceramic noodles, 1 tray of small ceramic noodles, 1 tray of small pebbly media and one empty tray. Along with, of course, the 4 sponges. It's a newer head, about 6 months old. Using smooth rubber tubes and the older type of connection to the filter, the one without the second lever to shut off the water flow. The second filter is an older head, 2+years old, using the newer ribbed plastic tubes and the newer connection to the cannister. First filter, 6.4L in 60 seconds=384 liters/hour Ok, the other filter. Contains 1 tray of big noodles, one tray of small noodles, one tray of carbon and one empty tray. Before cleaning: 9.25 L in 45 seconds=740 liters/hour <-- After cleaning, empty:9.2L in 45 seconds=736 Liters/Hour After cleaning, full: 8.9L in 45 seconds=712 Liters/Hour Each time was after letting the filter run for 5-10 minutes to make sure most air is out. Well, after all that work, I guess I'd have to say that the error in my measurements is probably greater than the difference in flow rate between empty and loaded, in this case. How...Unenlightening. I'm NOT happy to find out that my cichlid tank's filter is pumping about half what the I've got on the guppy's tank is. Probably would be better to do each test 3 times. Might retest the cichlid tank in a bit, I'm watching Andromeda though. Quote Link to comment Share on other sites More sharing options...
cees Posted August 3, 2002 Report Share Posted August 3, 2002 The only height that matters for the pump is how high the outlet is above the surface of the water. Correct, . My brain hit a blind spot. But I told you, never used a canister filter myself. Always used wet/dry and then pumpheight is absolute. Quote Link to comment Share on other sites More sharing options...
Derek Posted August 3, 2002 Report Share Posted August 3, 2002 The only height that matters for the pump is how high the outlet is above the surface of the water. The distance to go from the inlet down to the cannister and back up to the level of the water doesn't matter except for the resistance of the hoses. Basically it's like siphoning the water down and through the cannister and back up. So the pump only has to lift the water an extra inch or two, less if the outlet is at the surface of the water or below Sounds good in theory Ira but unfortunately you have forgotten at least one major part of the equation. That part, is the weight of the water in the outlet tubing. The higher the pump has to pump water in a given diameter tube the more weight of water there will be. A pump can only lift a certain weight of water before the force of that weight of water pushing down (under gravity) equals the force the pump pushing up. Increase the height of your cannister filter relative to your tank and I bet your flow rate increases. Quote Link to comment Share on other sites More sharing options...
Ira Posted August 3, 2002 Report Share Posted August 3, 2002 But, the weight of the water going up from the filter on the outlet side is forced upwards by the weight of the water going down on the inlet side. Want proof? Get your gravel vacuum. Stick one end into the tank, suck on the other end. Once the water is flowing plug it with your finger and hold the other end above the water level of the tank with the rest drooping. The water level in the end of the hose will settle at exactly the same level as the level in the water of the tank. It's EXACTLY the same with a cannister filter except there's a box in the system. The box doesn't change anything. If it works the way you believe, then the water would pour down to the lowest point in the hose and stop. Obviously it doesn't do that, it continues the rest of the way up. It's extremely simple. Ever hear of the phrase, "Water finds its own level?" Quote Link to comment Share on other sites More sharing options...
Ira Posted August 3, 2002 Report Share Posted August 3, 2002 Just swapped the connectors around so the newer one, the one with the lever to stop the water flow, is on my 200 liter tank. I tested it, it's now flowing about 540 liters per hour. So, about a 2/3 increase in flow just from that. And I did check, the other connection was clean, no blockages. Not sure how much the flow difference would be out of the spray bar, probably less than a 2/3 increase. I think Warren or Pegasus was saying they pulled the guts out of the older type and got a big increase in flow, probably would be similar to the newer one. That paragraph would be so much easier to keep track of if I knew the right names for the connections or some better name than old and new. Quote Link to comment Share on other sites More sharing options...
Pegasus Posted August 3, 2002 Report Share Posted August 3, 2002 Twern't me... mustabeen Warren Quote Link to comment Share on other sites More sharing options...
Derek Posted August 3, 2002 Report Share Posted August 3, 2002 Sorry Ira, you are correct. I obviously have the same "blind spot" as Cees. Been working with wet/dry filters and a sump for too long. Quote Link to comment Share on other sites More sharing options...
Midas Posted August 4, 2002 Author Report Share Posted August 4, 2002 Cheers Ira, thanks for your investigations. Looks like my 404 is doing a similar flow to yours, must be normal. Don't know how Fluval can get away with rating the filter at around twice the flow of what it does in practice. I think I'll go do a few measurements on my Via Aqua 750 and see if it is any where near the 1200 l/hr it is rated for. It is designed in a similar way to Ehiem canisters, so might operate a bit better. I bet Ehiem canisters put out closer what they are supposed to do. Anyone got an Ehiem canister? Quote Link to comment Share on other sites More sharing options...
Ira Posted August 4, 2002 Report Share Posted August 4, 2002 I've got a small eheim too. Only rated for something like 500 liters/hour. No idea how they can get away with rating them twice as high as they actually flow. I could see them being rated at, say, 850-900 liters/hour. That's conceivable for an absolute maximum running one empty with short hoses, brand new(Or slightly used if it maybe needs broken in). Only way I can think to maybe get 1300 liters/hour is running empty with the outlet hose on the floor, that way you've got the extra siphoning of the water added to the fluval's flow. Hmmm...Actually I think siphoning the water out with the hose end near the floor would probably get 700ish liters/hour of floor, seems like pretty close to it anyway with my gravel vacuum. Quote Link to comment Share on other sites More sharing options...
cees Posted August 4, 2002 Report Share Posted August 4, 2002 Actually I think siphoning the water out with the hose end near the floor would probably get 700ish liters/hour of floor, seems like pretty close to it anyway with my gravel vacuum. Quote Link to comment Share on other sites More sharing options...
Ira Posted August 4, 2002 Report Share Posted August 4, 2002 Hmmm, I think it depends which hose connection you have. The 2 lever one I think is basically no restriction, the other is a pretty big restriction. The media also isn't much of a restriction. I think 800ish is just the maximum the pump can do with zero head, I don't think anything else in the system is a very significant restriction. Quote Link to comment Share on other sites More sharing options...
john1 Posted August 18, 2002 Report Share Posted August 18, 2002 I have not tested how many liters my 204 delivers. All I know is when I change my media it flowed 3 times better. The flowrate does not only depend on the media, but also how TIGHT you pack it. Stuff 250 grams of wet fibre wool into one compartment and chances are your flowrate is ZERO. Go onto the Hagen's website and find out HOW they arrive at their specifications. Whatever the stated flowrate, the media and how it is applied is the mainfactor in the final flowrate. John PS please do not pick me to pieces now. he he Quote Link to comment Share on other sites More sharing options...
john1 Posted August 18, 2002 Report Share Posted August 18, 2002 I just got back from the Hagen site. And, I think it just hit me. One guy complained about too much flow. They said he can block it halfway without doing harm. They mention theirs run at 3600 rpm. Therfore ours with 240V runs only at 3000 rpm. so subsequently the flowrate of ours is 20% LESS than statet. Think about it. John Quote Link to comment Share on other sites More sharing options...
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