Substrate choices

I think this may have already created some thread, but I just joined so sorry for any repetition.

I want to upgrade my tank and start over with new substrate. I am told flourite is great as a base layer. I currently have a black sand base that was marketed as good for plants in my local pet store. It came in a bag that had water in with the sand, making it look like potting soil. The granules range from mostly very fine to round pebble size. This may actually be black flourite, I just learned, but I'm not sure.

I want to ultimately use play sand because I like the fine sand particles and the natural look to it and believe I can lay this over the base layer. Do I still need to vacuum down to the base layer given the compaction of sand which should keep particles at the top layer? Any other issues? I hear anaerobic activity may occur, but what downside risk does this pose? Thanks.

I was wondering about the use of sand in a freshwater tank myself. Would sand not disrupt the attributes of a freshwater aquarium?, making it a brackish tank?

But I belive that you do not have to gravel vac all the way to the bottom layer, which would be where you are wanting to place sand. The bacteria that you are talking about is good and you do not nessacarily want to get rid of that. I use flourite red as of right now. In my 10 gal tank I used eco complete and supposivly that is supposed to be really good aswell, turning the fish waste into usable nutrients for any live plants that you may have.

I liked the eco complete, because it was black, but since I gave that tank away all I have now is the flourite red experience and it works. It does what it is supposed to do. Its really up to you. But I would find out about using sand in a freshwater community first.

Thanks for the input. There is a link to a peripheral discussion on play sand below. I actually want this on top of the base substrate, not below it- if I read your comment correctly. The effect is appearance, the finer sand layer being what you'd see when looking at the tank.

The black stuff in the bag with water was probably Eco Complete. In addition to plant nutrients, it contains enough beneficial bacteria to start the nitrogen cycle. It's also kind of expensive. Flourite is a clay based substrate that comes in several colors and furnishes plant nutrients. As for sand, it was popular in aquariums in the 1950s and is still in wide use. You shouldn't use sand with an under gravel filter, and you shouldn't use anything that might react with aquarium water. Some of the substrate products sold for marine aquariums will raise the pH. Play sand will maybe work in freshwater aquariums so long as it has no additives. Put some in a small container of white vinegar; if it fizzes, don't use it. Better yet, spend the extra money and buy sand that is sold specifically for use in freshwater aquariums.

Thanks, John. What would be some examples of sand specifically for freshwater aquariums? Assuming you mean, actual sand particles and not finer gravel.

I haven't bought any of the stuff since the 1950s, but aquarium aquarium shops should have it. If you want to shop on line, try drsfostersmith.com. As an alternative, you can buy white aquarium gravel, but it will show any of the clay based substrates you add. I use pure laterite, because one ounce per gallon is all that's needed. Laterite is a tan color and it does not significantly change the color of the white gravel, although it takes a few days to settle.

I believe the 1950s white sand came from White Sands, New Mexico. My parents went by there once when I was a kid, and I put some of the sand in a jar. It was probably not radioactive.