Good day to you all I 've been doing a lot of looking at various filter systems. After careful consideration I' ve decided to go Old School, and use ATI sponge filters. I am working on a tight budget and physically limited as well, so any way I can save on materials and energy, while cutting back on physical effort, is an important issue. While my husband is willing to help with the physical part of tank maintence, I want to do as much as possible myself. With sponge filters, I can run them on an air pump or power head, and get filtration and oxygenation at the same time, and so conserve on energy costs. My question is... How long doe it take to seed a size IV ATI sponge? I will be using two of them in my 55 gallon tank, which I hope will give me a bit more time between water changes.. I dont want to remove either of my HOT filters until my sponges, which as of right now are separately working off my air pump, are sufficenttly seeded. Yes, I know.. Sponges are ugly and look "icky" cafter they get going.. But from what I've readthey do a wonderful job. I have also been fortunate to get my hands on a 29 gallon tank. So Sparky and The Flash, my two fanccy goldies, now have their very own private tank. At the moment I I am using the filter HOT that came with the tank, until I can seed probably two ATIsponges for it as well.