how much gravel/rocks should be on the bottom of a 20 gall goldie tank? how many inches high I mean? can i use real beach rock (rinsed cleaned and dried of course) or only rocks bought at a pet store? Can i use those round glass globs? This would all be to start out I mean? Which type of substrate is the best? thank you.
2-3 inches is a good cover. Buy a pound of substrate for every gallon of tank. Random gravel/rocks added to the tank can cause problems by leaching unsafe toxins into the tank. It is best to purchase something that is labeled for aquariums. The small glass blobs are fine. To be safe I would also purchase them from the pet store. As far as the best substrate it depends a bit on the fish you want and the look your going for. If you want bottom feeders it needs to be smooth fine gravel. Sand would be even better if you want a really natural look. Black is a great color to make the fishes colors stand out but any color of your preference will work
For goldfish, you want large gravel (quarter size), sand or bare bottom. Small gravel or rocks pose a choking risk for goldfish.
i read somewhere that the colored sand or was it colored gravel.. caused the water to change to that color?????
I have read this too for different brands but it won't happen with all of them. Before you add any substrate to a tank you need to rinse it really well with tap water until the water runs clear. It's a pain in the butt if you ask me but will save you a ton of water changes in the end. It will also give you a good idea if the colors will bleed. They shouldn't but it is a possibility. If the water changes the color of the substrate I would return it to the store and buy a different brand.
I just read on here somewhere today that the deeper the substrate the more toxins get trapped in and under it. sounds logical to me!