Substrate Depth question

[greatpratty]

So when you do water changes do you stir up the sand bed with the siphon or should you not disturb it. I have a 30 gallon with 2 fish and live rock so I don't think its overstocked and I only feed them 1/2 a cube of frozen food every other day so I don't think they are overfed.

Can I add some more live sand now even though my tank is established? will it stir up the fish?

 

[Lorna]

1 star for each meter squared would make a star unsuitable for most small tanks in fact I would barely make it with my 75 whose footprint is 48 x 18 which is my thought exactly. Most stars will not survive in smaller tanks and will eat almost everything before they starve to death. The depth of the sand bed is determined by the coarseness of the substrate. The finer the sand the less needed to achieve the same results.
a live sand bed needs to be replenished and added to to ensure the correct depth over years. It is not a put it in and forget it. Aragonite eventually will disolve over time due to its solubility at ph's higher than 8. I think that once you go with a dsb you must add new substrate regularily to ensure the correct depth. The following article and others linked to it provide a wealth of information on the subject.

http://www.wetwebmedia.com/deepsandbeds.htm

 

[mysis]

Yes but we don't know the persons tank size, it may be big, therefore it would be suitable for a few starfish...

 

[Lorna]

true we don't know the size and your 1 star for each meter squared is a good rule of thumb for the inexperienced or new aquariust. I was in a lfs and he was telling someone with a 20g to get a couple of sand sifting stars to keep the bed clean, bets on both will be dead in no time at all. Even then wouldn't you need to add them to an established bed that had lots of life in it? not a newly set up bed with little life?

Also the depth of the bed is dependant on the coarseness of the substrate, the finer the grain the less required to achieve the degree of denitrification.....most don't use the sugar sand or oolite which is the 3" recommendation. If you use aragmax or caribsea you would need 4-5 inches to achieve optimal effect.