Hi Aussiemum,
Yes, the axolotls should not be in the tank while all this change is happening, they will be thrilled by the end result though.
Sand is great!
Remove the axolotls and place them in tubs or buckets of fresh dechlorinated water and put somewhere cool and safe. Do not put the axies in the same container! Give them seperate containers and ensure there is enough water to dillute wastes and that the container has a lid to prevent escape.
Remove all gravel from the tank and dispose as you will.
Do not clean any of the other tank surfaces that remain in the tank, such as ornaments, tank walls, filter, plants, rocks that are remaining in the tank - this will preserve your remaining 'beneficial bacterias' that will take a bit of a blow when all the gravel is removed.
For sand subsrate: You will either need childrens play sand as this has been sterilized, or pool filter sand, or fresh water aquarium sand sold at most pet shops and aquariums. Do not use sand from the Beach or Marine sand.
You will need to wash the sand thoroughly - the old bucket method works well. Put some sand in the bucket, pour in water, stir up the sand and pour out the water, the run off will be cloudy the first couple of times, keep repeating this until the water run off is clear - put clean sand in tank.
Once in the tank, the sand needs to sit for about 24 hours - keep axies in their tubs during this time.
When the axies are ready to move back home, let the tubs sit next to the tank and when the waters of each are at the same room temperature, transfer the axolotls back into the tank - you can use a net to do this - don't put the tub water into the tank.
Cheers Jacq.
