i think ive figured it out.

[fishingaddict]

i think ive figured out why eheim are successful in biological filtration. 1) the intake is at the bottom and the return is on the top,

therefore the water must move through all the media. (other canisters have intake and return on top). 2) the return line is always

significantly smaller than the intake, so i guess the water has to sit in the media longer compared to other canister filters.  simple

things here and there that make eheim so effective for biological filtration.  these are all my assumptions. i havent tested

anything.  its just something i noticed since i just started using eheim filters.

[Hanson77]

Re: i think ive figured it out.

Well I know one thing......the one I got from you was well overdue for a media change....LOL!!!

Did you end up with any of the other canisters from Fish Depot when it closed down???

[fishingaddict]

Re: i think ive figured it out.

yea i got some other ones my cousin gave me. but i decided to use those to over filtrate my tanks.

[Anonapersona]

Re: i think ive figured it out.

The Classics are the best at that, especially the older ones that had no baskets. The newer ones have baskets and the seals between baskets and from around the baskets have to be perfect to keep flow going through all the baskets.

The other thing is that the velocity THROUGH the media is slow. You go from a 12mm diameter to a 6" diameter and so "dwell time" is long enough to actually do some good. In pond filter designs I recall reading some figures for required dwell time, can't recall the number, but flow rate translates into a canister volume, then the diameter of that canister tells you how fast the water velocity is then. The bacteria has to be in contact with the flow long enough to do some good.

One last thing, and the good reputation really rests on this.... you have to do the maintainance. Keep it cleaned and lubed and the Classic will last a long time.... I know of one person who reported his was 30 years old, with only impeller shaft and O-ring replacements. The Classic has a lot less parts than any other Eheim and so it is most likely to not fail (on the theory that more parts just means more things to go wrong - a mechanical engineers perspective on design durability)

[fishingaddict]

Re: i think ive figured it out.

the only eheims ive ran are the classics 2250 and 60, but ive heard the pro series are good as well. but i dont have experience with them.

[Anonapersona]

Re: i think ive figured it out.

I have the Classic (old style no baskets), the Pro, the Pro II, the Pro II thermo, and the Ecco. I also have HOT Magnum. I've had the Penguin Biowheel, Whispers of several sizes, a Fluval 303 (older version), and once babysat a tank with an AquaClear. And I've got an assortment of internal filters -- a few sponge type, an old style box filter, and a couple of power internal filters forget who made them.

Good grief, I need to clear out some equipment, still!

Hated the Fluval 303 -- air tended to float up into intake tube which is bad design. Classic is the best, Pro I is very nearly that good. Pro II has too many parts -- too likely to step on something or forget to put it back in or to lube it, and too hard to lube some of the o-rings. Ecco is a nice filter but sort of low flow rates. HOT is handy for mechanical filtration -- I run mine with eheim substratpro in the carbon canister, or the micron filter only for special needs.

If I had it all to do over again, starting new, I'd get the bigger Classic and add an inline heater. Then use either an Ecco or HOT or an AquaClear for secondary. I hear that the AquaClear can overflow if the sponges get dirty which is a big negative for me, but I did like that flow rate. Flow rate gives more mechanical filtration less bacterial action, but each has its uses.

[kewlkatdady]

Re: i think ive figured it out.

I hear that the AquaClear can overflow if the sponges get dirty which is a big negative for me, but I did like that flow rate.

I personnaly have used AC's for over 10 years...and I've never had one overflow...but part of the maintanence is to squeeze the sponge everyonce in awhile.

[eklikewhoa]

Re: i think ive figured it out.

The overflowing is really a non-issue since it overflows through the intake side back into the tank.....I have two that are doing that as I type...

[Anonapersona]

Re: i think ive figured it out.

Now that I think about it, I believe that report came from people who had inserted an extra sponge in the filter in an attempt to "improve it". I know my Whisper would overflow back down the intake tube as would the Penguin.

Sorry to have maligned the AC filter, it does seem to be the best in it's class and probably the best value for the money.