I have 2 Mbuna holding (Rusty Ido. and Obliquedens red tail) and I want to add several sponge filters to my sump to begin the bacteria colony on them.
When the bacteria colony establishes on the sponge, does the bacteria load in the main tank decrease to compensate for the added sponge filter?
When I remove the sponge filter to the new tank with the fry, will the tank readings be up due to the loss of the sponge filter in the main tank?
I realize that the size of the sponge filter makes a difference, however, in general does this take place?
It seems like a great place to get sponge filters going in the sump or even an established tank.
I am concerned for the established bacteria loads that we so carefully build up in the main tanks.

you will have no problem seeding two small in the sump of an established tank, i done it with mine. When you remove them just go easy on feeding for following week.

Excellent, thanks, so the existing bacteria colony does adjust down for the additional sponge filters.
So colonizing the largest sponge filters in a sump or existing tank will make a much larger impact on the bacteria, darn.
How long after adding the liquid jump start bacteria additive does it produce viable bacteria, like the kind that seachem makes?

I never had an issue taking sponges out of tanks with several filtration's (sponges and HOBs) I tend to keep a few extra sponges running in tanks so that I have one well bacterial-ised and ready to go if I need it.

Yea Fern,
after I found the 2 Mbuna holding, Im going to always have a few small sponge filters in my sump for the just in case scenario like you.
Never know when you might find a female holding or a sick/injured fish that you need a sponge filter right away. Good advice.

I always keep plenty of bacteria on hand to be borrowed. Extra cloth in my HOB's extra sponges running..... Borrowing decor helps as well, bacteria grows on most everything in tanks, so the more you can borrow the better off the tank will be.

Thanks again Fern, my fellow Floridian!!