Under sand substrate ?

[JazzyJeff]

In the next few weeks I will be setting up a 7x2x2 wild discus tank biotope, I will be using BD Aquarium sand as the main substrate, but wanted to add a nutrient rich plant substrate in certain areas to feed a few amazon swords etc, whats the best to use ? Tank wont have CO2 as it will be on a sump and low light ......

 

[James O]

John Innes no2. But if you are adding ferts the sword will be ok without tbh

 

[Alastair]

A light sprinkling of osmocote will really help as a food source for big hungry root feeders like swords etc but you only need a light sprinkle. 1 teaspoon per square foot if im correct.
Its long term too

 

[Lee Sweeting]

Original pond aqua soil is good, and only has a negligible affect your parameters.

 

[BigTom]

Original pond aqua soil is good, and only has a negligible affect your parameters.

I would definitely go with that over any of the John Innes mixes if you're keeping discus. Most of the JI and other commercial mixes will push your pH and hardness up considerably.

http://www.gardeningdata.co.uk/soil/john_innes/john_innes.php

 

[sciencefiction]

Soil-B&Q Verve food and vegetable planter. I've used it for a year in a shrimp tank so it's perfectly safe. It has no effect on the water hardness whatsoever. In fact water has become softer in my tank over time with the TDS, Gh and Kh lowering considerably. I was puzzled about it when I tested recently. But that's because I didn't do any water changes.
I recommend you add some natural red clay to 5-10% of the soil to the mix. It keeps the water crystal clear and provides extra nutrients such as iron, especially beneficial if sword plants are what you want.