Why are canister filters so popular despite their drawbacks? Rant.

[duanes]

The detritus that gets trapped in "any" filter become a nitrate precursor.
The longer detritus remains, the more nitrate it produces, one of the products of bio-filtration, is nitrate.
If a HOBs mechanical media is not cleaned regularly, it becomes a nitrate factory.
But the norm, is to tend to clean HOBs often because they easily and obviously get plugged up, and overflows over the mechanical cartridges.
A can that is cleaned often is no more a nitrate factory than any other type filtration.
Herein is the rub.
I often see aquarists that say, I haven't cleaned that can, in 2 months or more, and my water is clear.
Because in a pressurized can water channels thru fissures in the mud, becoming inundated with it isn't obvious, so not cleaned
This is (I believe) where the factory temp came into use, because nitrate is invisible, and in solution.

 

[neutrino]

Like a lot of things, filter cleaning frequency, canister or otherwise, is an empirical exercise dependent on a variety of factors-- number, size, and species of fish, what and how much you feed, filter capacity, design, and how you set them up with media, and multiple aspects of tank set up and ecology that influence where waste distributes in your system, how fast it breaks down, and whether or how much nitrates are processed.

It's very simple, if my filters get dirty faster I clean them more often. I've had 75 gal tanks filtered by a single, fast HOB that did just fine with a modest bio-load if I cleaned it weekly, tanks with canisters I cleaned about 4-6 weeks, and tanks with canisters that didn't need cleaning more than every few months-- and canisters are not all equal, some are easier to clean than others. I've had 75 gal tanks with two different HOBs where one needed cleaning more often than the other and then when I tweaked the media setup it was reversed.

The proof is in the results and for years I've had low nitrates.

 

[cvar]

A sump is too intimidating for me, so I prefer canisters. Totally silent cans. An open sump strikes me as noisy (splashy) and a potential humidity problem due to sump evaporation. Maybe that's untrue?

A prefilter was frequently mentioned here, to avoid the "nitrate factory" effect of excess detritus. Yup, I'm guilty. Lots of little plant leaf bits sneak into my canisters, which I need to clean often (monthly). And a big Eheim 2262 is a heavy beast, so I tend to procrastinate.

What kind of prefilter would y'all recommend for a 125g heavily planted tank? Is there something else besides a cylindrical sponge covering (or stuffed inside?) the canister intake tube? My pipes are 1.5 inch PVC. I'd prefer some kind of prefilter that is hidden below (eg, inside the stand), not seen in the tank itself. Perhaps a DIY clear inline can? Do y'all have ideas for an easy-to-clean prefilter? I'm kinda stumped.

 

[FJB]

There are a number of possibilities and preferences. Some people purchase things for this, I go cheap and easy. There are very fancy ones online, totally unnecessary.
I used to use sponges with a hole cutout (different sizes, shapes for different filters, but not anymore). What I have been using for several years now is pieces of plastic window screening, held with rubber bands. The pieces of screening last several months each, the rubber bands several weeks. I bought a roll of window screening four years ago, and it is still providing.
Shown are the set for one of my 6-foot tanks, including a Penguin 350, a Fluval Fx6, and an Aquaclear 110. I love these! and clean them every week while changing water.
Good luck!

 

[jjohnwm]

I don't use canisters at all, and HOB's only rarely...but all my tanks are drilled and equipped with bulkheads that are plumbed to my water disposal system, and I do a lot of water changing. So I still need something that functions to pre-filter the water leaving the tank, to keep small fish and other objects from being sucked into the bulkhead and down the hose during a change.

Since I am too cheap to buy something like that, I just use odds and ends from my parts bin; most usually this consists of a threaded plastic barbed nipple that screws into the bulkhead inside the tank. I swiss-cheese the nipple with holes, then take a leftover scrap of coarse Poret or other foam that is a bit longer than the nipple, cut it into a rectangle or cylinder, snip a hole into the end that reaches almost all the way through but not quite, and jam it over the barbed nipple. This lasts forever and is easily unscrewed and squeezed out if it starts to clog, which rarely happens. All my bulkheads for water draining are either 1/2-inch or 3/4-inch, but you can cut an appropriately sized piece of foam to fit literally any size of intake strainer that you may have on your canister or HOB and it will work just as well.

Since there will be water flowing through this foam 24/7 it will clog much more often than my drainage prefilters, but cleaning it will still be worlds easier and faster than actually cleaning out the filter itself.

 

[cvar]

I'll need to create something like that. But I may need a bigger surface area? Here's a photo from yesterday's canister cleaning (just 1 of 2 cans). It shows how a month of detritus forms a thick slime inside the can. The 6-inch thick stack of Matala media (at intake end) is filled with decaying plant bits. Then after that, a 1-inch thick layer of Pinky floss tries to stop that gunk from reaching the 9-inch thick layer of sintered glass media beneath it (at canister output end). PITA to disassemble and rinse it all away. I do need a prefilter. Yes, tank water is crystal clear. Nitrates are 10-20, and our tap water measures 10.

 

[jft]

Canisters ARE GREAT EHEIM CLASSICS ALL THE WAY. Running since 1992.Hugh media compartment and QUIET. Been doing tanks forty years sumps, hangon, canisters etc . Most bang for the buck if you GO Eheim.

 

[Something Fishy Here]

Well to answer the original questions rather directly, I havea canister and had one on for over a decade on my last tank for the same reasons stated early on. It's all in one box, easy to use closed loop system, and I'm comfortable and confident in whats happening in it. I'm willing to do the maintenance to keep my tank healthy. I have 1 tank, and my wife was nervous enough about having 90 gallons of water in her brand new kitchen. I can't imagine her opening the stand and seeing an open top sup with wires and hoses coming out and all the dirty cleaning going on. I'm intimidated enough without having to convince her its the best option. If I lived alone I'd even consider taking out cabinets to put in more tanks and take a stab at a sump. But I love my wife and kids and I still have a nice large(to me) tank.

 

[CaliFishKid]

I'll need to create something like that. But I may need a bigger surface area? Here's a photo from yesterday's canister cleaning (just 1 of 2 cans). It shows how a month of detritus forms a thick slime inside the can. The 6-inch thick stack of Matala media (at intake end) is filled with decaying plant bits. Then after that, a 1-inch thick layer of Pinky floss tries to stop that gunk from reaching the 9-inch thick layer of sintered glass media beneath it (at canister output end). PITA to disassemble and rinse it all away. I do need a prefilter. Yes, tank water is crystal clear. Nitrates are 10-20, and our tap water measures 10.

View attachment 1502939

1 month on what size tank and with what stocking? My canisters have never looked like this at all.. and especially not after just one month. And that's even with a densely planted 90g tank. What filter is it? Your parameters seem just fine if that's truly where your tap is with nitrates though.

 

[jpcampbell123]

I use eheim 2217 on the longnose gar growout plan on moving them to a pond set up once they outgrow their 75 never had an issue with canisters I clean the canister out once every other month