Canister Filters... Important

Discussion in 'Filters and Filtration' started by steed1172, Dec 25, 2009.

  1. steed1172Well Known MemberMember

    Now I've been meaning to upgrade for awhile but it's not been happening...
    now that Christmas is passed, i have extra cash to spend.
    i look at canister filters and they are SOOO expensive, then i look at their GPH and it's relatively low compared to my HOB filter... and about 3 times more money,so why am i paying loads more? i JUST read on the sticky about GPH's.. why do you need LESS GPH in a canister filter than a HOB. are they really that much better?

    what is it that makes them better(and worth more..)?

    lot's of questions while i can still think of them :p

  2. cwb141Valued MemberMember

    I haven't used a canister filter before but I do know that the gph doesn't have to be as high as an hob. I'm not sure why (maybe amount of filter media) but I'm sure someone else will be able to explain it. They are less obtrusive than an hob in that you can put the tank closer to the wall, put the canister inside the stand, etc.

  3. AquaristFishlore LegendMember

  4. lew2000Valued MemberMember

    Canister filters provide much more surface area (through the use of ceramic pellets) for bacteria to grow on. However, with canister filters, depending upon the type you look at, you can get some dead spots (with minimal or no water flow due to debri).

    As to gph, hob versus canister: hob's are above the water line, thus do not have to move any water up a a length of hose to empty into the tank, (sometimes refered to as head pressure) and are usually just moving through mechanical media and maybe bio-wheel(s). Canister's obviously have to move water through a combination of filter (mechanical) media and bio media. You don't want large gph through a canister as you want water to have time to through the media and allow the bacteria to do what they do. On the other hand, hob's move a lot more water to perform the same action on a smaller bio-media surface area. Sounds counter-intuative doesn't it.

    So with a canister (and for me with any type filter) don't look at tank size recomendations, but look at gph. With any type canister filter - the longer the return hose the less gph overall - of course, as well as what media; mechanical versus bio-media. I usually subtract 20% of the rated gph.

    I personaly use a wet dry canister to avoid creating dead spots. But with a canister filter - the bio-media provides substantialy more surface area for bacteria even versus an hob.
  5. David CWell Known MemberMember

    Another reason for the GPH difference is a HOB tends to draw in quite a bit of the water it just finished filtering since the intake is directly below the output. With a canister filter, they tend to have the intake on the opposite end of the tank as the output so you get fresh unfiltered water being drawn in. Also, canisters are designed so all the water is forced through the media, none of it can just flow over the top and not even come into contact with the media so 100% of the water is filtered.

    Hope this helps.

  6. steed1172Well Known MemberMember

    ahh... very helpful, i forgot that canister filters used the pressure, if i used a flow diffuser on my HOB filter to divert the output on either sides of the intake, it would improve filtration greatly?
  7. cwb141Valued MemberMember

    Some filters that are basically hob, but set up like a canister in terms of intake/output, are the marineland eclipse (hood) systems. I have a hood that fits a 29 gallon (37 tall) and it works exactly like the penguin/emperor filters which are hob. However, the filter system runs along the entire length of the tank so the output is on the opposite side of the tank from the intake. For around $100 you can get the filter, hood, and lighting fixture (plus bulbs) for a 29 gallon or 37 tall.

    So, they're a great beginner product. I'm not aware of hoods like this for over 37 gallon tanks and with your tank size (55 gallon) this wouldn't work. If someone was looking into a filtration system for a smaller tank these would be worth taking a look at.

    I have a 75 gallon tank that I'm starting up in late January, *knocks on wood*, and I have a hob filter that will run for the first month+ while I plant the tank. I'm not too worried about filtration while there are no fish, but once I start stocking the tank I plan to add a canister filter.

    What brands of canister filters are reliable and exceptional in filtration? Fluval? Eheim? Marineland? Other?
    Last edited: Dec 27, 2009
  8. lew2000Valued MemberMember

    for what it is worth - i use a combination of a canister and hob's, on my non sump tanks. While i use a eheim 2229 for wet dry filtering - i use a hob to move a lot of water for mechanical filtration - as the intake is 3/4 down from the water line, versus the intakes of the canisters that are at the bottom of the tank. David C. is right that some portion of the output water will get drawn into the intake - even with the intake tube 3/4 down from the water line. I also use a spray bar for my canister ouput(s) which also reduces gph slightly. Newer design canisters versus the old ehiems and others of that design, are designed to reduce the possibility of dead spots and have a better flow through all of the media.
  9. steed1172Well Known MemberMember

    thanks for all the info guys!!....i just looked on drs foster and smith's website and it says that the "Eheim Plus 2217-37" can do a tank upto 160 gal... and only gets 263 GPH... is that normal GPH in a canister filter for a 160gal?? or is this filter special..

    EDIT: it also gives volume and water circulation along with GPH, is there a way to use this in a calculation/formula (or am i just trying to get to technical ;) )
    Last edited: Dec 27, 2009
  10. cwb141Valued MemberMember

    Are you planning on switching to a canister for your 55 gallon?
  11. steed1172Well Known MemberMember

    welll...if its better than my aquaclear 110 i might, or il switch one of them to low and use both for extra filtration and flow..(or il work out room for the canister filter on another tank somehow..)

    P.S i've already ordered it lol, it gets 275 GPH and has a volume of about 5 gallons, meh
  12. MeenuFishlore VIPMember

    The gallons the manufacturer rates the filter for doesn't really mean much. Look at the flow rate to decide if it is enough filtration.

    I have a Fluval 305 I've been very happy with. It's very silent - I only know it is working because I see the flow of water jetting out. I've heard good things about Eheim canisters as well. Honestly, when I was deciding between the two, it came down to looks, because it sits on a counter for the world to see. lol
  13. steed1172Well Known MemberMember

  14. MeenuFishlore VIPMember

    lol... I typed that before your last post, and walked away for a few minute... came back and posted it, and you had posted in the meantime. That'll teach me to stay at the computer!
  15. JayseeFishlore LegendMember

    Your AC110 will do a great job on your 55, unless it's full of goldfish or something.
  16. steed1172Well Known MemberMember

    thanks. jaysee, it does do a good job.

    and yes, serves you right for leaving me! lol

    thanks again i have learned much from Fishlore!!

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