Reason for replacing sand

Question
I am looking for a new person to maintain my tank, and the guy I interviewed said it is necessary to remove old sand and replace with new sand every three years, is that true?  I recently had lost two fish--due to the fact the first maintenance guy didn't clean my tank for two months because he couldn't find the time, and when he did I lost two fish. My 75 gallon tank is three years old, never diseased or lost  a fish due to any reasoned other than what was  stated above. I have only 5 fish in the tank.  Tank is cleaned once a month.  So, is it true, does the sand need to be replaced?  If so, what is the reason?

Answer
Hello Renee,

The simple answer for your question: no, you definitely do not have to replace sand every 3 years. in fact that would do much more harm than good.

although throughout the life of a saltwater tank the sandbed collects all sorts of things. this is why it is good to stir the sand often or get some sort of sand sifting fish or invert. because it can trap harmful elements in the sandbed for quite some time, and if some tine you want to change the rockscape or something and you disturb the sandbed all those toxins are released into the tank.

in other words, a healthy sand bed is a fairly deep bed (2-6 inches) that you stire often with some sort of stick or rod. or simply purchase a sand sifting fish or invert.

hope this helps. and just a helpful hint, if you are paying someone to visit your tank monthly i would increase the visits. the tank should have at least 2-3 water changes per month in order to keep water quality top notch.

hope that helped a bit!

Marcus.