It depends..some people like a deep bed because it will host bacteria that can break down the waste products such as nitrates, nitrites and ammonia.
This would be 4 to 6 inches.
Other people have a shallow gravel bed of 1/2 to 1 inch.
Some considerations are if it will be a reef tank or just marine fish?
hi,you should never use marine sand in any freshwater tank because its is made up of crushed coral and therefore your pH value will increase which is not ideal for plants and most fish apart however you can go to argos for play sand jewson for kiln dried sand or b&q for play sand which ever one it will work out alot cheaper and look the same as it would silver sand however it will need cleaning alot more or you can use filter wool/filter floss and should clear within a day or 2 depending on turnoverAnswerAnother word for marine sand is "live sand." It's full of microorganisms and small invertebrates. None of the animals in live sand can live in freshwater, so they'll all die and contaminate your tank.
Marine sand usually has salt and additives in it for salt water aquariums so it is not a good idea. There are freshwater sands that would work much better and there would be no question of suitability.
Is a type of sand that has salt
Using sand from the Great Salt Lake in a saltwater fish tank is not advisable. The sand may contain impurities, organic matter, or contaminants that could harm the tank's ecosystem and fish. It's best to use commercially available aquarium-grade sand specifically designed for marine environments to ensure water quality and the health of your fish. Always rinse any substrate thoroughly before adding it to your tank, regardless of the source.
Sand dollars
crab
Depends on the depth of the tank
If other fishes are present in your tank, then it may not be a good idea for the skin of the sand dollar will begin to rot and spoil the tank. So first remove the sand dollar dry it in the sun and clean it with bleach. Then you can decorate your fish tank with the cleaned sand dollar.
No you mook
5cm
yes.
I have a 120 Gallon aquarium with sand. They love it.