Canister Filter - What to put in it?

[welchrock]

I have a Magnum canister filter, rated to filter up to 100G. I only have a 46 gallon tank but know that I can be utilizing it better.

The flow and suction is great, but I have persistent debris and microbubbles in my water. I don't mind the bubbles that much but the debris is really getting to be a noticeable problem.

I have tried a few different mediums inside the canister but don't think I've even scratched the surface of options. Here's what I've tried:

1. a blend of activated charcoal and ammonia chips inside a foam sleeve.
2. entirely activated charcoal, 50% replaced monthly, inside a foam sleeve (current).


My tank isn't particularly over-stocked, so I didn't notice any difference with the ammonia chips and went with 100% charcoal. I want to try a blend of sand and activated charcoal but wanted to get some help first.

So any help provided is much appreciated!

[emc7]

Put in the "micron filter" and run it for 48 hours and see if that picks up the debris. If you run the micron filter long-term it will clog, but its good for a quick clean up. You can use it with a gravel washer, too. Then put it back with media and sleeve. I usually use carbon or carbon and crushed coral, but it doesn't matter. Any media that won't fit through the screen should do, just don't change it all at once.

[welchrock]

I'm definitely going to utilize the micron filter - I've used it in the past with minimal results but it's time to give it another shot.

After 48-72 hours of that I'll look for improvement. If there's only some or none at all, i think I'm going to try a layer of course sand and a layer of activated charcoal - am I nuts to think this would work?

Am I also nuts in thinking that I should be able to use the same filter-medium arrangement all the time? Seems like I shouldn't have to 'polish' my water and should be able to find a filter-medium arrangement for my canister system that works near-perfect barring scheduled changes.

[emc7]

If the sand won't fall through the grate, it would work. Don't get any in with the impeller. No idea if it would work better. I haven't tried diatomateceous earth with this filter. You could put a bag of it in the media container and see what happens. I think you are right about fine particles drifting right through the course charcoal. Have you tried filter floss over the intake? A lot of canister filters have even coarser media (ceramic rings) which do good biologically filtration but suck at the mechanical.

[welchrock]

I'll definitely be on the lookout for properly-sized sand/small gravel.

The fine particles do seem to be flying through the charcoal...and I really would rather not have to periodically polish my water with the fresh micron-inserts.



Two questions:

Filter floss would be a fine foam sponge over the intake port I'm assuming?

By bag of diatomateceous earth do you mean filling a mesh bag with the granules and then putting that into the filter portion of the canister...or not using a mesh bag?

[emc7]

I would try a very fine bag inside the media canister. No guarantee that the water would go through it instead of around.
If the water just flows around it, it won't have any affect.

We used to polish water and gravel wash our filthy tanks with a diatom XL filter. This is a basically a strong canister filter with a floss bag and a glass jar. What made it effective was a shot of diatomaceous earth stuck to bag (to get it there you effectively clouded the whole tank then let it clear). The diatom skeletons act as a very fine filter and catch stuff at the micron level. The magnums claim to get the same effectiveness from the micron filter (which you clean with bleach and reuse), but you can't run then continuously or they clog. I've since seen "diatom filters" for whisper and other HOB power filters. They seem to be a filter cartridge with is filled with D.E. that you use in place of other media. I still have some DE (my Diatom filters are dead) and I've been tempted to try it with the magnum. I'm pretty sure it would work with the micron filter, but that is still a one-shot deal. To use in the other container you'd need to find a way to keep it in, but let water flow though.

By filter floss I mean stuff like polyester quilt-batting, fine and fibrous. But a fine sponge should work too.

There are two sleeves available for the marine land canisters. One is thin foam and the other is more like a filter pad. The filter pad one fits the larger canisters (350), but you can sew it smaller and use it in the HOT. If the pad fits the media container tightly, it will be more effective.

[SueM]

Go get one of the square sponges used in AquaClear filters, cut a slot on one end to fit your intake, this will at least grab the larger particals. While the internal media grabs the rest. And make sure that your 1st stage box has a fine pore sponge or cut floss.
One word of warning, do not use sand unless it is in a fine enough mesh bag that not one grain can get out.

[emc7]

Originally Posted by SueM

1st stage box has a fine pore sponge or cut floss.

I think this is the issue. The magnums are cylindrical with a mesh cage for media. Around the cage sits a very thin sleeve. It comes in foam or coarse floss. The foam is really thin and not recommended for the bigger filters because it can clog. The floss tends to stretch out and gape and let the water flow bypass it. My mother altered my sleeves on her sewing machine to fit the media container again.

[jerrybell]

I have many cannister filters, and here's what I do with much success:

In the first stage, I have a very corse foam pad.

The second stage is a medium pad

The rest of the filter is packed with bio media - rocks, stars, balls, that sort of thing.

When I use the micro filter pads, I notice that the water is completely clear of any suspended solids, but the filter has to be cleaned almost weekly, or it loses flow. I've found the recommendation above to be "good enough" and allows the filter to go without cleaning for 3 to 6 months at a time, without losing flow.

[welchrock]

Wow emc7 you really hit the nail on the head with your post about the sleeve - I've noticed that the sleeve is a loosey-goosey mess, but never really thought that had that much effect on the filtration. I'll definitely be sewing it tighter (it's stretched out at least 40%) and am hoping for good results. I'll also buy a new sleeve and try that in a few weeks.

Jerrybell - I like your suggestions and will try something like that on my own. Am I safe to assume that the 'first' stage of filtration would start at the bottom of the canister? Clearly I am a bit confused on exactly how a canister filter works.

On a larger level - it's really annoying how little instruction the Magnum model 350 canister filter I bought came with. You'd think for the prices that they go for that a decent instruction manual regarding actual water filtration methods would be included!!

[emc7]

1st stage is where the water goes first, right? In the magnums, the water goes in at the outside top and out at the bottom center. The cage is designed to force the flow from outside to inside rather top to bottom or bottom to top like in other canister filters. I wonder what would happen if you dispensed with the media container entirely and filled it the whole cyclinder up with foam.

[welchrock]

Thanks emc7. Now that I look at it that makes a lot of sense - I think what I'll do is this: sew outside sleeve to fit tightly. Fill internal cage with, from top to bottom: fine foam, activated charcoal, diatomaceous earth (or similar, whatever is needed to be big enough to not escape).

I know filling it from top to bottom doesn't make that much sense - but filling it from outside to inside would be near-impossible unless they make a sub-internal cage.

Lets hope none of this experimentation negatively effects my fish!

[emc7]

I think the only way it would hurt the fish is if you throw out all the established media and have to re-cycle. I like the magnums, but even with a big filter, I feel better if a tank has two filters. Even a little sponge with an air-line would get you a biology backup in even of failure (like the filter clogging and giving no flow).

[jerrybell]

In general, canister filters pull water through the bottom to the top, so the bottom most section of media is first, and the top is last.

I agree whole-heartedly with emc7 on multiple filters. Every aquarium I have has at least 2 filters. On my smaller tanks, I have a Rena XP2 and a pengiun HOB filter. I'll only ever perform maintenance on one in a given month.