Got 3 Filters, Which To Use Where?

[phantomlink]

Ok, heres my dilemma. I have three Aquaclear 110 filters (110 gallons) I will call them A, B, and C. I have two tanks these will go into a 125g and a 67g so heres the thing.

Filter A is currently in my 30 gallon tank with fish in it, its fully cycled and part of its sponge was taken from an established AquaClear 70 from my mom. It houses 9 harlequins, a guppy, 3 corydoras, 3 pictus catfish, and a striped raphael catfish

Filter B is currently hooked into my 67 gallon and it just finished cycling two days ago, both ammonia and nitrites go to 0 within 12 hours. Part of it's sponge was taken from Filter A when I was setting up Filter B and C to get cycled.

Filter C is also hooked into my 67 gallon tank and is cycled as well, this sponge is untouched because I was tired of the other two filters have weird pieced sponges instead of a single brick Also when the time comes if a filter dies later I'll have a large piece I could donate to it.

I'm probably going to finish building my stands this weekend which means I can finally put the tanks on them, put in decorations/sand and they will be good to go

What I want to know is this. When the time comes to move the tanks/filters which should I put where? Filter B and C are cycled for 67 gallon, they dont have enough bacteria to handle 125g worth of fish stock so they will need more cycling time. I was thinking of putting Filter A in the 67 gallon since that tank will only house a few catfish, and I am hoping a 30g ready filter for 17 fish can handle 5-6 in a larger tank. While I double the ammonia in the 125g when I put Filter B and C in it. Will that work, or should I use a 67g filter in the 67g tank and move A into the 125 but it has less bacteria then B or C.

Confusing I know. I cant introduce the fish slowly to the 125g because my fish store I'm going to is so far out of town I can only save money ( fish are twice as expensive or more here ) so when the tank is fully stocked in bacteria all the fish will go in at once

 

[thereverendturtle]

Any way you go will work.

 

[phantomlink]

anyone else? I dont know how much longer it will take to cycle a 30gallon filter into a 125 then it will a 67g into a 125

 

[JohnDyer]

Once you have sizeable colonies of both ammonia > nitrite and nitrite > nitrate bacteria, it won't take long at all to double or triple their population. You can move both B and C in the 125, dose it to 3ppm, and it should be gone within a few days.
The majority of the time it takes for a cycle is to build up a good size colony. From a few individuals to a group that can process several mL of ammonia takes hundreds or thousands times of population doubling. From 67 gallons to 125 needs only roughly 2x population.

 

[phantomlink]

All the fishless cycle guides all say 4-5ppm and I've been building it up to 5ppm every 12 hours or so to keep the bacteria fed. Would 3ppm make them grow faster? I plan to fully stock at a single shot so I need the 5ppm colony built asap