Hi there 
My filter is on it's last legs, it's means of filtration is just a sponge in the bottom half, and i wanted to swap to a Fluval u2 which came with my tank, but is second hand. I have completely cleaned the filter from top to bottom, and taken out the 3 compartments.
So my questions are ...
1) there are little white cylinders in the middle blue compartment, still in their plastic packet ... what are these?! Maybe biomax things!?
2) For the other 2 black compartments i have taken out the sponge bit as it was very used and gross, so could i replace this sponge with some of the one from my filter, and that'd make it safe to put straight into my tank?
And 3) For the poly/carbon cartridges that slide in along side the filter part,they have been pre used in the other people's tank, so should i wash them reaaaally thoroughly, or leave them out all together?
Thankyou so much for your advice, and apologies in advance if these were stupid questions
My filter is on it's last legs, it's means of filtration is just a sponge in the bottom half, and i wanted to swap to a Fluval u2 which came with my tank, but is second hand. I have completely cleaned the filter from top to bottom, and taken out the 3 compartments.
So my questions are ...
1) there are little white cylinders in the middle blue compartment, still in their plastic packet ... what are these?! Maybe biomax things!?
2) For the other 2 black compartments i have taken out the sponge bit as it was very used and gross, so could i replace this sponge with some of the one from my filter, and that'd make it safe to put straight into my tank?
And 3) For the poly/carbon cartridges that slide in along side the filter part,they have been pre used in the other people's tank, so should i wash them reaaaally thoroughly, or leave them out all together?
Thankyou so much for your advice, and apologies in advance if these were stupid questions
