Originally Posted by AaronT
People have been using laterite as a low substrate for decades. It does help, but you will still need to dose the water column with macronutrients. If you choose to use mineralized topsoil in addition to the laterite the need for dosing lessens dramatically. Topsoil is the top fertile layer of soil.
Thanks for your response and advise.
You have certainly clarify a lot of doubt and help me understand the issue much better.
Just a little side tracking………
Before going into planted tank, I used to keep a lot of fish in my 2 5 foot tanks.
I feed them heavily ( mainly large discus and crown loaches ) with pork heart meal.
To keep the water reasonably low in nitrate ( I have a 3.5 ft sump biological filter to take care of ammonia and nitrite ) I have a continuous flow arrangement to pump out about 500 liter of water each 24hr and replace it with tap water with a float valve connected to the tap water inlet to the sump.
With that, I found that I am able to maintain NO3 level at about 20 ppm ( no plant ) without any other water change regime ( more than 1 year now ) and the arrangement has been so convenient and maintenance free.
When I convert one of these tank to planted tank months ago, I was told I need to maintain proper level of water column fertilization ( macro, micro and TE ) and I have to stop the automatic water change system because I believe the continuous flow system will lead to high lost in these water column fertilizer.
But without the continuous flow system and the high fish load ( and heavy feeding, hahaha, I just cannot resist that ), I have problem with BBA which I think is due to high phosphate level arising from the fish load and feeding.
With a little twist of luck, I have just found a very cheap local supply of various fertilizer and minerals ( K2SO4, chelated Fe and trace elements that is phosphate free ) for hydroponic gardening.
I believe I can put these micro nutrients into gelatin capsules and embed them into the substrate for slow release as well as enrich the water column by dosing directly with litter consideration of cost.
With that in mind, I intend to restart the continuous water change system to minimize the phosphate level and hope that this will lead to less BBA problem.
As always, your comment and advise appreciated.