Planted Tank Guru
Join Date: Jan 2010
Location: Contra Costa CA
Mine nested on a flat rock. The substrate was a fine gravel, maybe 3/8" diameter. Mom and Dad Ram moved some gravel to make a hollow area when the babies were ready to leave the flat rock. The Rams had no problem with the fine gravel.
Sand works well, too.
Soil Master Select and Turface can help soften the water, they remove KH from the water allowing the pH to drop.
Do not use coral sand or any other substrate that adds minerals to the water.
I have peat moss in most of the filters. This also helps to soften the water and adds the organic acids that many soft water fish appreciate. Rams are one species that do like the things peat moss does to the water.