Tank cycling question

[coolperson]

if a upgrade my 50 gallon already cycled through and i get a 100 gallon and if i put the exsisting water from the 50 gallon into the 100 gallon then it would be half full then if i just fill the rest with odanary water then add salt would the 100 gallon tank have to go through the cycle

 

[papafish]

Not sure but I would think It would have cycle,
but on the other hand It could be considered a
50%water change, good one I have never did a 50%
water change. but if it were me i would mix my 100
gal and just let it cycle and keep my fish strong
and heathy in the 50 till it was done.
just my o2

 

[bdubbya]

I would have to agree with papafish. Even though your using water from an established tank you still need to give the tank time to establish the bio-filtration (lr,dsb,bio wheel,etc.). Otherwise your putting your fish at risk.

 

[cwfish]

Adding the 50 gallons from your cycled tank to the new 100 gallon tank will no next to nothing to help cycle your 100 gallon. If you want to move all your fish from the 50 to the 100, move your bio-filtration equipment (LR,LS,Wet/Dry,etc.) from the 50 and add it to the new filtration equipment for the 100. Run both sets of equipment for a month or so and then slowly take away the 50gallon equipment from the 100 gallon tank and you should never see a cycle.