Seeding new 75 gallon with 5 gallon filter?

I currently have a 5.5 gallon betta tank (just a betta, a nerite snail and malaysian trumpet snails inside). Sponge filter inside.

I have a 75 gallon arriving today, that I plan to stock with goldfish in a month or so. I have (2) new sponge filters also arriving for this tank.

I would like, if possible, to move the betta, and her sponge filter only (leaving water in existing tank) to this new 75 gallon to give her a sort of vacation home for a month before the goldfish get here, then bring her back to the 5 gallon after.

Can I do this safely? If not, I don't want to do it.

Here was my thoughts: put new sand in new 75 gallon, put both (2) new sponge filters in, put betta sponge filter in, put 75 gallons of brand new water, add Stability/Prime, make sure temperature is 78f and then bring betta over - can do this all in one day? It'll basically be an empty tank minus the sand, would the betta care or would she just be happy there's now 75 gallons to swim in?

Alternatively, while all this is happening for a month, plan was just to leave an airstone running in the snail tank, but no filter. Any issues there?

Then, in a month, take betta's sponge filter and betta, move her back to the 5 gallon and put new goldfish into their 75 gallon.

Thoughts?

 

I think you might struggle to effectively cycle the 75 with the filter from a 5. Bettas have a low bioload compared to a goldfish.

 

It seems you have thought about this a lot but to be perfectly honest, I wouldn't do it. Moving your betta and sponge filter is going to do little to help cycle the 75 gallon tank.

It would be best to just leave the betta where it is and cycle the big tank with liquid ammonia along with a bit of fish food.

 

it would be ok for the betta, but its not really going to cycle the tank/new filters. bioload is too low.

the 5g filter might actually decline due to the significantly lower concentration of Nitrogen.

you probably won't even need the 5g filter in there. the 75g would dilute the Nitrogen to trace amounts, maybe not even enough to register on the API liquid tests.

 

It would be interesting to know if the airstone is holding enough nitrifying bacteria to keep the 5 gallon cycled without a filter.

It would be interesting to know if the 5-gallon filter built up nitrifying bacteria over time and has more bacteria than Many people think.

But in my opininion, its not worth risking.