u/JournalistSafe7422

Im buying this used tank off facebook marketplace and it comes used with a small amount of water already inside the gravel. Im a little concerned with how my fish are gonna react to new bacteria thats already built up inside the gravel. Ive already had an issue in the past where my fish got the ick, luckily i was able to treat it properly but im being a lot more careful now.

Im thinking of removing as much water as i can from the new tank and replacing most of the water with old tank water that my fish are already in

If you have any tips or suggestions on how I should handle this process id greatly appreciate them!