Basically the substrate is a mess, its a mixture of about 3 different colours and its covered in algae, i want to change it to a single colour substrate, possibly black, my nitrates are climbing so a water change is due, i was wondering if it was possible to remove say 80% of the water then scoop out the substrate and put the new stuff in, while i was doing that i planned to keep the fish (10 neons and a betta) in a bucket of tank water with the heater in untill i change the substrate and replant the plants, would any of this present a problem?
Thanks