I was wondering what the best thing to put in the bottom of the tank was... Marbles? Gravel? Is there a downside to either one... Things to look for when choosing?
don't choose pointy rocks or ones with sharp edges, other than that it is mostly a matter of presonal preference. i use sand in 2 of my 3 tanks at home. a 2-1 sand to blue gravel ratio in the other (looks great) and blue gravel in my betta tank at work, being it is only one gallon it has a ugf and i can not use sand with it. but I lovethe look of sand. again will not work with a ugf.
It's really a matter of personal preference, although there are some fish that prefer sand to gravel. I personally use natural coloured gravel as I like the natural look and I find that my plants grow better in it. I have heard of people using marbles and I imagine it would look stunning. I don't think that sand can be cleaned in the same way as gravel and I've heard that sometimes "dead spots" can occur in it.
depends on the type of fish that you are putting with the fish. with cichlids, who are notorious for digging, you do not want to use sand as it can clog up a filter with all the sifting that they do.
Not being argumentative here , but you can use sand in cichlid tanks, you just have to cover your intake with a sponge. The Fluval 2 sponge inserts work well as filter "condoms" (as I like to call them) on Eheims. They fit quite nicely, and look alot nicer than using other sponges wrapped around and secured with fishing line. It's also easier to remove them for cleaning.
the sand does need cleaning and I vac it the same way you would gravel. i then fill my bucket with clean water, treat itand use the vac in reverse order to siphon the sand back into the tank.
I use very fine gravel,2mm stones.I find this to offer all the benifits of sand (fish that like to burrow and dig can) but without the hassels of sand (clogged filters,difficult to clean and more prone to anerobic areas) i also find that plants get much better root holds in gravel which is a must when you keep larger fish.