From a UGF to a Fluval 2?

[NineNails]

Hi Everyone & Merry Christmas
I have 12g tank with small smooth gravel 1.5 inch deep
I'm finding it difficult to keep the plants in my tank healthy for very long. They don't root very well.
I've had a look through some old posts and come to the conclusion that, a ugf is the biggest thing not to have if you want live plants.
I have a Fluval 2 filter pump that is brand new. Could I use this instead?. I'm guessing that if I was to use it, the best idea would be to run it in the tank with the ugf still running for a month??. To cycle the filter medium??.
Then, could I just leave the ugf in place?, and simply remove the lifter pipe and cap the hole?. I really don't fancy having to strip the ugf out
Thanks for any help
Si.

 

[NineNails]

Here's a problem with this my novice brain has come up with today.
If I was to leave the old ugf in place disconnected, maybe the water in the channels under the ugf may become stagnant??. Is this a possibility also??
Si.

 

[BobK]

It may become stagnant but I think the bigger problem would be all the crud under the filter plate(s). How long has the tank been running and how long since the UGF has been cleaned out? I would definitely get the plate out and really clean the gravel well once the new bio-filter is established. Yeah it'll be a pain to clean and re-plant the tank but I think you'll be better off. 12 gallons isn't that big and water quality is even more important in small tanks because concentrations of poisons build up much more quickly.