New Member, New-ish Tank

[nikbud]

Firstly can I say that I've been reading this forum for a couple of months and the level of help and expertise here is outstanding (grovelling over!)

Secondly a bit of background, just bought a Fluval Edge (27l) from my brotherinlaw. He's had it "running" for a couple of months, and having followed the typical LFS advice - bought it, put in safestart, and some fish 5 rummy nose tetras and (his words) a fighting fish. After these had died he was sold 10 cardinal tetras, after a couple of days 9 of the Cards died in less than 24 hours with the last one dying a day or 2 later. So today i put the filter and media in a bag with some tank water, emptied the tank and brought the whole lot home including heater and API test kit, in exchange for 50 beer chits. The plan is to have 1 dwarf puffer depending on the results of research on wether the filter will cope with the bio load and the lights are good enough for live plants.

Thirdly, my plea for help and guidance;- bearing in mind the 9 cards dying in less than 24 hours should I use the filtermedia to kick start the fishless cycling process, or would I be wiser to replace the filter media and start completely from scratch in case some sort of infection killed the Cards? I will be scrubbing the tank out (no soap) and replacing the sand. I would also reuse the stones he has in there - they are from a bio orb accessory kit. Also the filter media includes activated carbon, would i be correct in changing this for some silk wool (I think thats what its called)?

I have a "decent" theoretical knowledge of cycling etc but no hands on experience - unless you include trying to keep a couple of goldfish won at a fun fair in an inappropriate tank 5 years ago!
Any and all advice will be welcome.
Thanks, nikbud.

 

[OldMan47]

You have your hands on a filter that may be partly cycled but not ready for fish. I would set it up and do a fishless cycle on it. The fish deaths are almost certainly due to adding a huge bioload with little or no bacterial colony established. On the other hand, messing with fish in the tank for a month or two will have begun the cycling process to a degree in that filter. It is always easier to bring along a partly cycled filter than to start from scratch. As far as changing filter media, the more you can carry over to the new setup, the faster things will move. Carbon is not exactly a great biomedia but if it is carrying a large fraction of any established bacteria, why not wait until the new filter is well established before getting rid of it? The cycle may surprise you by going fairly quickly if you use the entire filter in your tank. Do you have any idea how seldom water changes were done before all the fish deaths? It may be that fish were added to a tank that high ammonia levels to start with and it just killed them outright.

 

[waterdrop]

Yes, excellent description by OM47. You'd be much better off taking the partially cycled filter directly on in to a good add&wait fishless cycle as described in our rdd1952 fishless cycling article. This would show you definitively when the filter was fully cycled, after which the bacterial colonies in it would just get stronger from there on out and you could begin replacing fractions of the media with better biomedia choices.

~~waterdrop~~

 

[nikbud]

Thanks, I was hoping that was the case. I was unsure wether the carbon would be releasing bad stuff as its been in there so long.
fishless add and wait starts now.