diver21 Posted September 2, 2009 Report Share Posted September 2, 2009 can a canister filter work when its above the tank or does it only work being below it? Quote Link to comment Share on other sites More sharing options...
SamH Posted September 2, 2009 Report Share Posted September 2, 2009 Depends on what model it is. Most work below, check the instructions. If you haven't yet bought it but are planning ahead, perhaps ask someone who has it. Quote Link to comment Share on other sites More sharing options...
diver21 Posted September 2, 2009 Author Report Share Posted September 2, 2009 havnt got the instructions, got if free from someone who got out of fishkeeping ages ago, it had been in the garage for about a year but the impellor still goes and i got it working for a little bit, its a Via aqua professional Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted September 2, 2009 Report Share Posted September 2, 2009 must be below the tank. the way the impellor works is that it pushes water up. gravity must do its job to send the water down. Quote Link to comment Share on other sites More sharing options...
spoon Posted September 2, 2009 Report Share Posted September 2, 2009 it will work above the tank just it could be difficult to prime Quote Link to comment Share on other sites More sharing options...
Ira Posted September 2, 2009 Report Share Posted September 2, 2009 What? The cannister doesn't care where it is in relation to the tank. The only time it would matter is when the cannister is empty if it's above the tank it's harder to get it filled by siphoning from the tank into the cannister. After that you could hang it from the ceiling if you wanted. Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted September 2, 2009 Report Share Posted September 2, 2009 ok. this is new. the cannister filters i have dealt with have to be below the tank. infact some of them have to be a certain distance below the tank. reason being that there is an optimal level for the height between the tank and the filter - any higher and the gravitational force on the water will make the speed slower (downflow) and; any lower, and the pump cant push all that water back up too well, and it slows down any how. the manuals even mention distances/ cant be bothered reading it now, but if i find the thing tomorrow ill update this. the actual flow rates are only achieved when the distance between the tank and filter is optimal. That's why the stock tubing comes in such a weird size, its not really to make people buy more of it or find substitutes. ive tried different levels on eheims and the difference was immediately apparent. Quote Link to comment Share on other sites More sharing options...
Ira Posted September 2, 2009 Report Share Posted September 2, 2009 ok. this is new. the cannister filters i have dealt with have to be below the tank. infact some of them have to be a certain distance below the tank. reason being that there is an optimal level for the height between the tank and the filter - any higher and the gravitational force on the water will make the speed slower (downflow) and; any lower, and the pump cant push all that water back up too well, and it slows down any how. the manuals even mention distances/ cant be bothered reading it now, but if i find the thing tomorrow ill update this. Except that's how it works in an open system like a sump, not a closed loop like a cannister. The pump does not have to lift the water back up. Gravity does that all on its own. The only reason you want to keep the cannister closer to tank level is to minimise hose lengths, longer hose=more friction=lower flow. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 2, 2009 Report Share Posted September 2, 2009 If the canister is above the tank the disolved gasses in the water will slowly accumulate until the pump starts to capitate (pump air) and will air lock and stop working. Quote Link to comment Share on other sites More sharing options...
livingart Posted September 2, 2009 Report Share Posted September 2, 2009 If the canister is above the tank the disolved gasses in the water will slowly accumulate until the pump starts to capitate (pump air) and will air lock and stop working. that has been my experience in the past, haven't trid with the more modern filters though Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 2, 2009 Report Share Posted September 2, 2009 Having it above the tank will cause a negative pressure that will encourage dissolved gasses to come out. Most pumps are better at pushing than pulling. Quote Link to comment Share on other sites More sharing options...
Morcs Posted September 2, 2009 Report Share Posted September 2, 2009 I put my CF1200 on a table so it was even height with the base of the tank - in the hope that the pump doesnt have to work quite as hard and hence better flowrate. This didnt work well as it kept making the pressurising noise like when air is in the system. Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 2, 2009 Report Share Posted September 2, 2009 If your pump is 3 metres below the water level on the tank then it has three metres of water each side of the pump therefore having positive 3 metres pressure and negative 3 metres pressure so the only work it has to do realy is against the friction loss in the pipes. The same thing would conversely apply if it was 3 metres above the tank. Quote Link to comment Share on other sites More sharing options...
Scottie841 Posted September 2, 2009 Report Share Posted September 2, 2009 My 2213 will not work above the tank. As p44 said they are designed to work below the tank not above it. Also the impeller will push better than it will pull so you are best to have the filter under the tank. Quote Link to comment Share on other sites More sharing options...
phoenix44 Posted September 2, 2009 Report Share Posted September 2, 2009 here it is: 1. REmember, this is a gravity fed system. For it to work properly, all the installation instructions below must be adhered to. >The cannister base must never be below 4.5ft (1.5m) below the water level >Hosing must follow a straight path from the filter to the aquarium rim with some slack but no loops >The water should never be below more than 7in (17.5cm) below your aquarium rim. >NEVER install the filter above the water level (In bold) >Intake tube should not be placed in close proximity to an air source straight from my fluval manual. it applies to any and all fluvals on the market. same deal with the eheims. Quote Link to comment Share on other sites More sharing options...
si_sphinx Posted September 2, 2009 Report Share Posted September 2, 2009 I find that if my canisters are beside or above my tanks then they accumulate air in them and eventually stop. same the the new fluvals, they get air in them but dont stop, they just pump the air out into the tank. so IMO i would keep it below the tank, then you wont have to worry about anything and probably best to replace the impeller also to reduce any further damage to the impeller well etc. Quote Link to comment Share on other sites More sharing options...
Caryl Posted September 3, 2009 Report Share Posted September 3, 2009 I have a manual for Fluval 104, 204, 304 & 404. It says; Place the filter in desired location beside or beneath the aquarium. Since the filter uses gravity feed, ensure the filter is stationed below the water level of the aquarium. The it has an outlined box with these words in bold Filter must never be installed above water level. My Jebo 819 manual says "It must use below the water surface of the tank". It alo says "Move the machine by holding its bottom, not only the ouches, other wise the ouches and the machine body will be broken, water will enter and cause accident" :lol: And then there's the "In case of accident, pull off the power plugs of this machine and other electrical appliances which may also cause leakage of electricity and fire." Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 3, 2009 Report Share Posted September 3, 2009 Once again, if all else fails---read the instructions. Quote Link to comment Share on other sites More sharing options...
diver21 Posted September 3, 2009 Author Report Share Posted September 3, 2009 cheers guys, looks like ill need to get this tank off the floor somehow, next problem, ill need to build a stand now for 160l tanks, peferably 3 high, can i use 75x50 or should i stick with 100x50 to build it, and any advise? Quote Link to comment Share on other sites More sharing options...
Aquila Posted September 3, 2009 Report Share Posted September 3, 2009 You should have your tank some what off the ground anyway otherwise you'll have to empty it with a container instead of just siphoning it out...and with it on the ground, forget about ever being able to clean the substrate. Quote Link to comment Share on other sites More sharing options...
diver21 Posted September 5, 2009 Author Report Share Posted September 5, 2009 lol half my tanks are on the ground without substraite. im about to build a stand to hold 20ish 160l tanks for the start of my fish room Quote Link to comment Share on other sites More sharing options...
alanmin4304 Posted September 5, 2009 Report Share Posted September 5, 2009 Tanks are OK on the floor if you have a pump Quote Link to comment Share on other sites More sharing options...
whetu Posted September 7, 2009 Report Share Posted September 7, 2009 Just to add to the info in this thread for future reference, the manual for the Eheim 2026/2028 says "the upper edge of the pump head should be at least 10cm below the water surface. It is better to place the filter underneath the aquarium." Quote Link to comment Share on other sites More sharing options...
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