PlanetCatfish.com

Hi everybody,

I have two 20L tanks that get weekly 20% water changes and have Aquaclear 70, 3-stage filters. Physically I need to find a less demanding way to keep the tanks clean and have considered both canister filters and diatom polishers. Having experience with neither, I'm hoping someone here could help with some advice. I keep reading that with a canister filter (particularly a very good filter, like an Eheim) a fishkeeper can go for *months* (sometimes as much as 6 months!) without needing to service the filter. But what does this mean, exactly? I've already written Eheim with the question and am awaiting a reply, but I thought I'd ask here, too. With the Aquaclears it's advised that I change the media at the 2 and 3 month marks, with a canister, would that mean I wouldn't have to change the media but for every 6 months? Also, I've never had a filter that was a replacement for gravel vacuuming---for anyone with a canister, are you able to gravel vac less, too? If so, how does this work? Additionally, is one type of canister recommended over another? Would a small canister create too much water current for two 20Ls (and can you "split" the lines of a canister to service two tanks simultaneously?) Can a canister be set on a counter *next to* a tank, or must it be placed below? Also, does anyone have experience with diatom/micron water polishers? Are they more beneficial or more of a headache in the long run? (I was thinking that with the extended periods between maintaining a canister, it might be helpful to polish the water---for potential nasties, diatoms, etc---regularly.

Finally, a question that's plagued me since I got it wrong on a math test in the 3rd grade: Regarding two types of cats, BN Plecos and Otos--how often should they be fed as not to over-feed (with the higher metabolism, I'd imagine Otos have to feed nearly constantly.)

(((Thank you so much)))
It's so very much appreciated!!!

Regarding the cleaning of filters, I never follow any manual. Last Sunday I cleaned 2 Eheim aqua pro II 2028 for the first time since October, I think (I don't write down when I clean them). They are connected to 350 l tanks, in the upper range of what Eheim advises.

After installing a filter, the flow will decrease soon, the next time it will take longer. The explanation? after a while, bacteria start to life in the filter, degrading amonia/ nitrites towards nitrates, but apparently also degrading any matter which used to be alife towards its components, amongst which nitrates.

Still, my experience with small tanks is that they require reletively a lot of care - for lack of any compensation

Regarding the otocinclus, the do have to feed almost constantly, and as this is nearly impossible in export/import circumstances, they often arrive very meager, and nearly dead. However, as they feed on algae, which grow by t4hemselves in the tank, I dont feed them as in putting foodstufs in their reach, they take care of themselves.

The same goes for Ancistrus - in larger tanks
[Mod edit: Change "por" to "pro" typo --Mats]

Like Bas Pels, I don't follow any guide lines on cleaning my Ehiem Classic filters. I clean them when their return flow drops below whatever I feel is too slow. This is about every 2-1/2 times a year for me in heavily stocked planted tanks.
I have either a sponge filter or wet/dry filter also running in these tanks. Not necessary but for the heavier than recommended stocking levels I have.

A 20 long can be equipped with an Ehiem Classic 2215 and be cleaned twice a year under most conditions.
I use Ehiem Prefilters because they extend the time between cleaning by blocking the larger pieces of crud.
It won't hurt to continue using the Aquaclear because it too, will extend the time between cleaning a canister filter.
Most of the established brands of canister filters are very good, I just happen to like Ehiem filters best.

The Diatom filters are only useful in event of gross mismanagement leads to bacterial/algae blooms.
Best to correct the cause.

If you are keeping Ancistrus sp 3 and Otocinclus in 20 Longs you will need to feed them because you can't have enough surfaces in one to supply them with all the food they need. Feed an algae wafer once a day or every other day.

A big canister filter requires infrequent cleaning - how often it actually needs to be done depends on many factors, including how "dirty" your fish are. Certainly, it's realistic to expect to clean a large canister filter months apart - if you do it more often, you are probably just wasting good filter bacteria.

I don't have any other type of filtration on any of my tanks, e.g. Diatom filters. [I do have a couple of tanks with internal filters, but that's it].

As to "too much current", we had that sort of discussion quite recently, and the current in most rivers (where most of the fish we keep in tanks come from) have a much higher "turnover" rate than a really big filter in a small tank. A 20L (75 liter, roughly) would have a turnover rate of 10x if you put a 700 liter per hour (200 gph or so) filter - which is far from "high". 700 lph is a medium sized external filter.

Splitting external filters is best done via a sump-system, which is a different technology altogether. The principle of a external canister filter is that it's taking in as much water as it gives out. However, if you feed (slightly) more water into one tank than what you took out, you will end up with a lot of water on the floor after some time - and it would be very difficult to control such that both tanks get exactly the same amount of water taken out and filled back in. [I have that problem with my water storage tanks, I pump water from one to the other, but the flow back to the "pump from" tank is by a simple pipe. This means that if the pump forces more water over than the flow from one tank to the other will allow, the "destination" tank will eventually overflow - not a problem, it's got an overflow pipe to the drain, but my "source" tank is then also emptying to some extent].

And your filter needs to be places such that the top of the filter is always under the surface of the water, as the "intake" of the filter is by gravity, and the water is pumped back into the tank. If the filter is higher, it MAY work, but it's not designed to work in this way for extended periods of time.

And yes, you can use a gravel vac with the external filter, no problem.

Also don't confuse "filter cleaning" with "water changes". I still do approx 50% water changes each week on my heavier stocked tanks, and 20% a week on lightly stocked tanks. I just don't spend every weekend also cleaning the filters.

--
Mats

More on the recommendations:
I have used Eheim Classic filters for my fish-room. I also have a Eheim Pro2 2028 [like Bas's]. The Pro2 filter is a more modern design with filter baskets so that you can easily have separated sets of filter media, and all you really need to do to clean each set of media is to dip it in some used aquarium water a few times [the water gets VERY mucky very quickly]. The Classic filters are simpler, which reflects in the price, and do the same job, but filter media is just "one compartment", so if you use modern filter media such as "Stone Macaroni" [Eheim Ehfi-Mech or similar] or substrate [Ehfi-substrat], then you need to pour/dig it out of the filter canister into a different container (such as a bucket).

My most recent purchase is a TetraTec EX1200. It is similar to the Eheim Pro2 - perhaps not quite the same quality, but the basic design is quite obviously a copy of the Eheim Pro2 design. Price was about the same as the Eheim. There were two factors that convinced me of this filter:
1. The shop didn't have a suitable size Eheim Classic 2217 that I would have liked to get.
2. The price was MUCH better than buying a second Eheim 2028 for the same tank.

I have only very ancient experience with other external filters, and that's probably not helpful.

--
Mats

Hello,

I have an Eheim Economy model which works fine, it was relatively inexpensive (around $100 with shipping), but I would not buy it again as its outflow is slow. You are better off getting the Eheim classic or pro.

For the money the best filter I ever had was an AquaClear 300. This filter is over 15 years old and still works.

I have also had Fluvals which never lasted too long 5 to 7 years and 2 pengium biowheels that are pretty good but they cost a lot in filter media.

Regarding the media, I no longer replace anything other than the filter bags on the biowheel. I just use sponges and the ceramic noodles that came with the fluval and the eheim as media. When you clean the filter just rinse the media.

About recommended maintenance, IMO the time to clean the filter is when the outflow is slow. It could be 6 months in a lightly stocked tank or a month in a heavily stocked tank.