fluval canister filter: how to service?

[wendy2]

so I have this problem- I have a 30 gallon tank. I used to have a hang-on-the-side filter, things were good for years, the filter broke, so I replaced it with a fluval 205 canister filter; I dumped the ceramic bio media from the old filter into it, and it has sponges and a bag of mixed charcoal/ nitrogen removing media.
All is well, the transition to the new filter goes seamlessly. The instructions that come with the filter are a big vague on how often to replace media/ etc. so I decide to continue with my old schedule of once a week a 5% water change and once a month rinse the filter sponges and replace the charcoal, never touch the ceramic bio media.
After the first filter cleaning the tank crashed big-time. All the angel fish died within a day, the water was cloudy; I added bottled "bacteria for filters" and waited, and things got better. Did another filter maintenance, another crash. Decided to maintain filter once every three months. Have done that twice, and after each the tank has crashed. Last one was this friday; the only fish left alive are the cory catfish and an apparently indestrucible betta.
The fish go into distress almost immediately after my re-starting the filter, almost as if there is some horrible toxin being released? the school of tetras I put in to replace the angels were all dead within 6 hours after this last filter rinse.
Testing indicates the water is perfect, slightly hard perhaps 120 ppm.

what am I doing wrong?

 

[DragonFish71]

Here's what I do with my Fluvals (models 305,404 and 405) every other week.

I take out all trays and rinse the canister and ceramics with tank water. Using a toothbrush I clean the impeller and it's housing. If I have peat or carbon I replace those packs with new and I replace my floss with new. I rinse the sponges in either tank water or I keep milk jugs (thoroughly rinsed) that are filled with dechlored water and use that water for rinsing the sponges. To refill the canister before hooking it back up (easier to prime it that way) I use the water from the jugs. (i keep about 20 jugs on hand)


I've never had any problems with my tanks crashing after cleaning them like this.

 

[mfdrookie516]

I have a similar routine to Jamie. I have two (305 and 405) on my 150g. I do one filter every week, alternating so that they're each done every other week. Here's what I do:

Disconnect the hose from the filter I'm cleaning. Use the hose to fill a 5g bucket about 2/3 way full. This also helps get the brown gunk out of the hose.

Take the top off the filter and sit on a paper towell (they always have water that doesnt want to drain out).

Remove the trays of ceramic media and place in the bucket with the water drained from hoses. Take the sponges out of the plastic holder and place in bucket as well.

Let tank drain half way (this is for my 50% weekly water change) with python after doing vac. Start filling back up. (this part is up to you on how much you do and your routine for water changes).

While the tank is filling back up, I empty the can, rinse with tap, and take a paper towel to clean out the can. I use the hoses once again to fill the can back up about 2/3 way full. I 'swish' the baskets around getting any loose gunk off the ceramic. I squeeze and 'unsqueeze' (i guess that word will work) the sponges until all the gunk is out of them. I place the media and sponges back in the can.

Take a brush and paper towel, remove the impeller cover, and clean the impeller and cover. PUt impeller back in, cover back on, lid back on can, hook up hoses.

To prime the can, i just open the valve on the hoses and it fills it back up. Once the water level is where i want it, I close the valve on the canisters, turn them on, and slowly open them to avoid a brown cloud of gunk.

This is how i've done mine for close to a year now with no bad results.

 

[nickt]

Like the others said, be sure you rinse your media in tank water or declorinated water. If you are cleaning the sponges in tap water, you may be killing off too much bacteria. I would also give the ceramic media a rinse in tank water too, it might be gunked up and not behaving as it should. You should be able to rinse all of the media in the filter in tank water or dechlorinated water without sending your tank off the deep end.

With that said, I'm troubled by how quickly this comes on. Was your tank overstocked with fish? If the fish are stressing almost immediately, I have to wonder about something in the water that is being added or maybe anything else you might be adding at that time. How long after the filter cleaning did the water cloud up? You say the water tested perfect. PH was OK? Like between 6.0 and 7.5? Ammonia and nitrites were 0? Nitrates below 40? Temperature OK? How does the water smell? I would expect that if water clouded up a day or so after a filter change and fish died, that you would for sure see some elevated ammonia or nitrite levels. Is your test kit working ok?

 

[wendy2]

I was rinsing in un-treated tap water, that may be part of the problem.
I am actually wondering if we have something wrong with our tap water- I've always been a bit disturbed by how "hard" the water tests for one thing; maybe there is something toxic in it that is removed by the charcoal filters, so it only kills when first introduced? who knows. I think I will try gradually swapping out the tank water with distilled water and see if I can soften the water, then I'll try a filter-rinse with non-tap water, and if nothing horrible happens I'll try introducing some other fish. The betta seems perfectly happy to have the tank mostly to himself anyway...