Filter Changes

[Mentat]

I have the tetra whisper EX 20. I'm not sure if there is enough room to put in two filters, but I can see. Right now there is only one filter and I'm in the process of tank cycling. My ammonia dropped to 0ppm so I added more. I also added Seachem Prime, which is supposed to make the ammonia more digestible for my filter.
I'm confused if we are talking about filters or filter pads. If you are cycling your tank the filter should be running. Also, you should only add Prime to dechlorinate tank water when initially filling tank or when adding new water during a water change. Adding extra Prime to water volume will sequester ammonia and nitrites and the bacteria you are trying to get going on filter will starve.

So from what I've gathered is that avoid replacing the filter pad entirely and rinse it off with siphoned water (presumably during a water change?).
Yes.

But when I rinse the water on to the filter pad, would that be enough to season the filter? Or should I leave the old filter in the water for a few days?
You rinse the old filter pad in tank water and reuse it. When replacing filter pad rinsing the new one won't have any effect. If your filter can handle two pads could "seed" the new one by running with old one for a couple of weeks.

Also, to be clear, your third suggestion is to open up the pad and replace it with the material you suggested? If I am getting the right idea, do I replace everything and just leave the case of the filter?
You would only leave the filter pad frame so can reuse again and slide into the filters pad slots. When I say filter it means the whole assembly; not the pads.

My biggest concern is that the tank is cycling now, but wouldn't having a new filter pad destroy the whole process? Apparently the filter I have now has a seperate biofilter, so maybe not?
If you have a new filter pad running there is no need to mess with it until flow slows down. You can still rinse it during every water change to increase flow and efficiency. If your filter has a separate bio-pad; then no need to worry when you replace the white poly filter pad because the bio-pad will have enough bacteria to prevent a mini-cycle.

Also what exactly is Seachem's pond matrix?
Matrix is a sintered glass media made by Seachem. It's very light and porous so it sustains huge bacterial colonies. Pond Matrix is same material but in much larger (around 2X) pebble sizes. It's what I use as bio-media in all my aquarium filters (Aqua Clears 70s and 150s).

Hope above answers your questions .

[elliotulysses]

The matrix looks like a good product! Also one that eliminates the use of filter pads at all? Especially if using the pond type? Would this drastically reduce the time to cycle?
I know that having a good tank is a must, but I feel so antsy to get these guys in a bigger tank. They have enough room to swim and move and hide, but I just can't wait to see how much they love their new, long tank. (:

Also, while I put the prime in to raise the water level, I think it technically unbinds or whatever after 48hours so tomorrow should give me an accurate reading for sure.

And yes! You did answer most of my questions. Thank you very much! It's a blessing to a new, panicky owner that you are on this forum!