Originally Posted by DappleDoxieGirl
Thank you for the information, Byron. I read all of your stickies at the top of the forum and enjoyed them. In the past I have used laterite (if I remember correctly is a reddish brown substrate) with gravel and had a decent outcome. The hairgrass is just a dream, I think it's gorgeous. Do you recommend something that looks like the hairgrass? My water is naturally a little on the hard side. Currently I have 4 mollies in my 55 gallon tank, but plants have not fared well in there because a I have 3 young koi that destroy everything except for some mondo grass and java fern. I have some decent daylight bulbs in there, and the two species are surviving so far.
Laterite is reddish brown, it is simply an iron clay. It was "the rage" back then, now it is seldom mentioned except in high-tech tanks. One drawback of laterite is that is is just iron, and iron is a toxic metal that in high enough levels will kill fish and plants. The "balance" I mention frequently in the stickies is all-important. I would go with plain small gravel.
Substrate cover plants can be tricky, being so far away from the light means the light has to be somewhat more intense to reach them; your 20 long is not as high as a 20 regular, so that is an advantage. If the low plants are kept near the front where they will receive the most light from above and perhaps daylight in the room (?) they may well do OK. It's a bit of an experiment. All tanks are different; the biological balance in them is dependent upon fish (the type of fish, size and number), plants (fast growers, slow growers, floating...all affect the biology differently), minerals in the tap water, fish foods, light, pH, temperature--all this. What will grow in your tank may not grow in mine, etc. As one should choose the fish to suit your given water, so I believe should the plants suit what you can provide for them. Try this or that plant, if it thrives good, if not, move on to another.
Koi would see plants as a free meal.