Sand & Anaerobic Bacteria + other Q's

[Fishman02]

I told a friend of mine, who has been in the hobby for many years, that I would like to change my substrate from gravel to sand. He told me that it may be more natural for my fish and look nicer, but it has many pitfalls, one being anaerobic pockets build within the sand decreasing the water quality of the tank. He also said it is more maintenance and harder to clean and I am better off with gravel.

Here are my questions:

1. Is this true about sand?

2. If I decide to change from blue gravel to a cichlid-type gravel, how long should this process take in my 46g tank?

3. In a general sense, what is the approprate size tank to house adult mbuna for many many years without upgrading? Would a 75g do the trick? Everybody on this board speaks about upgrading to 125, and 150, and so on, and since I have limited space and will stay that way for a while I want a tank that will not be upgraded at all to house 10-15 adult mbuna. (PLEASE ANSWER IN GALLON NUMBERS ONLY ie. 55, 75, 125, etc)

[SGypsyMermaid]

one of the reasons that everyone always says go for the biggest tank possible is that 15-20 mbuna will eventually become 100 mbuna unless you are very disciplined in the fish-buying department, and you remove all baby fish. do a 'quick search' on this site using 'sand' as the keyword, and you will come up with a bunch of discussions on sand as substrate.

[tom]

Yep, lots of discussions on sand substrate...and here comes another as I've been experimenting a bit with different substrate grain sizes/depths:

Your friend didn't steer you wrong about possible dead spots, but you can avoid that problem for the large part by (1) using coarser grade sand, such as that used for pool filters, (2) keeping the substrate depth to a maximum of an inch (3/4" works fine for me), and (3) getting decent water movement along the bottom of your tank (may not be absolutely necessary if the substrate is very shallow).

As far as sand being more diffcult to clean and maintain: Not really. Again, if you use pool filter sand, you'll find that the initial cleaning is not that much tougher than it is for gravel (as few as a half-dozen rinses until the water runs clear). Same with its maintenance: Just vacuum it by moving the siphon head bare millimeters above the substrate itself, as you carefully rake the sand. Of course, you should protect the intakes of your power filters (easily accomplished with nylon stocking).