If it is an "all-in-one" cartridge that is filter floss with carbon inside, just rinse it once a week in tank water or dechlorinated water. Most of the filters use those kind of cartridges. If the cartridge becomes too old or starts to fall apart, put a new cartridge in the filter but keep the old one behind it for a week and monitor for ammonia spikes.
Sakura i have a question. I don't cycle my tanks so i am not sure how often you need to change the cartridge in the filter for 5.5 gall tank? Or should people just rinse the cartridge?
Thank you so much as always:)
Wild daphnia would be okay but I'm not so sure about wild daphnia from a lake that is high in mercury. If the person decides to go ahead and use them, rinse them well first in dechlorinated water using a conditioner that removes heavy metals.
Oh, in regards to the metal in the hammock. I can throw it out to the rest of the mod team but I know we have a problem with too many stickies already. We're in the process of trying to organize the stickies so once that is done, maybe we can add one about the metal. :)