New Tank, What to so with fish?

Earlier I posted that my 75 gallon tank had developed a 1 inch hairline crack. To be on the safe side, I am going to replace it. My question now is what to do with the fish in that tank. I have a 30 gallon as well as a 45 gallon tall that these fish would happily co-exist with, but both would be heavily overstocked. My concern is that the filters will not be able to keep up with the increased bioload. The 30 is filtered by an Aqua clear 70 and the 45 by an aquaclear 110.

Since I plan to use two days once I get the new tank to complete the changeover, would I simply do daily water changes in the 30 and 45?

 

Can you lower the water level below the crack so you can spread out the bioload.

 

What filter do you have on the 75? Can you move the filter from the 75 to the 45, and run the filter from the 45 alongside the filter on the 30?

 

Hello G...

If you take no more than two days to change tanks, the fish will be fine. You don't need to necessarily change out water in the temporary tanks, just don't feed the fish. Aquarium fish can easily go a couple of weeks without food. If you've been feeding them regularly, they'll have a small fat reserve that will last a few days. Fish waste takes time to dissolve in the water and won't foul the water in just a couple of days.

Old

 

In answer to Smme82 the new tank is going in the same place as the one with the crack. Sooner or later, it's going to have to be drained and the fish moved somewhere, while the new tank is set up.

As for Bbarb27 suggestion. I'm running two Aquaclear 110's on the 75. I could take one of the filters from the 75 and have it run in tandem with the 110 that is already on the 45. This was something I was planning on anyway to preserve the BB

This is what I thought as well, Old, but wanted to make sure by asking those that may be somewhat wiser than myself.