New filter established tank

[Matt20324]

Hello- I have a 29 gallon established tank with several mollies, tetras, swordtails, pleco and crawfish. I was running 2 HOB filters for a while but have stepped up to an eheim classic 250. Huge improvement btw but not the point of post. Do I need to temporarily keep one of the HOB filters in place to acquire beneficial bacteria in canister or is there enough in the rocks, artificial plants, etc? Thanks for responses.

 

[HooKooDooKu]

Not familiar with any of the filters you've listed... but you don't want to simply remove two working filters and replace them with one uncycled filter.

Your filter media is where most of your nitrifying bacteria is located. Sure, there will be some on the rocks and such, but not enough to counter act the loss of all the bacteria in the established filters.

You need to do one of two things:

1. Run at least one of the old filters with the new filter... for a few weeks... to give the new filter time to build up a bacteria load.

OR

2. Place filter material from one (or both) of the old filters in the new filter.

 

[Matt20324]

Yes the filters I had were the "hang on back" aqueon quiet flow 30's. I did remove one of them and added an eheim classic 250 canister filter. I did leave one in place though and was planning on doing so- just curious as to when it would be safe to discontinue the remaining aqeoun filter. The only media I was using charcoal inserts and of course the "bio" diffuser that comes with the aqueon. So I'm not sure how to add that media to the canister because the canister came packed with plenty of other media.
So- is two to three weeks adequate before discontinuing the old filter or should I keep it operating longer. Thanks.

 

[HooKooDooKu]

Since it sounds like it shouldn't be a problem, let it run for three weeks.
Afterwards, the only way to know if it is safe to remove is yo remove it and test water parameters at least 24 hours later.
However, if the filter dries out, you will kill the bacterial colony. So when you remove it, it would be best to do a partial water change and keep the old filter submerged in old tank water in a bucket until you know you don't need it anymore.

 

[Matt20324]

That is a good idea about keeping old filter in water until
I confirm that I have bacteria in new filter media. Thanks!