Do you need to keep adding plant substrate?

[CrazieEddie]

I'm thinking of going to a planted tank in the future, but I was wondering about the susbtrate. I'm thinking of using flourite, but I had a question...
Do the nutrients in the substrate get absorbed by the plant(s), which requires me to replace or add on to the substrate every few months/years?

[aquak]

When I started my tank, I had very little success with the same kinds of plants that started doing much better after it had been running for a year or so. My impression is that they get their nutrients from the waste products we're always cleaning out, some of which gets left behind. I do use plant fertilizer cones, but they are always the same size and I was using them pretty much from the start, so I think the fish are fertilizing my plants. I don't uproot them, just clean around them, as the roots get rather large and settled in. Anubias and jave fern don't need any anchor or fertilizer and they are still my fastest growers, but the others are getting established as well. I don't use high powered lights for the sake of the fish and since that also affects the growth I only get plants rated for low to moderate light. I do have a full spectrum light and my fish look much better in it. In fact, the whole tank looks better with it, but I'm not sure it has a better effect on the plants.

[phoenixshade]

Eddie--

It really depends on the substrate used. I have found that after about two or three years, I need to replace laterite substrate. Flourite should have a similar lifespan. The iron content simply gets used up, especially if you have a heavily planted tank.

There are laterite products that can be added to the substrate in the vicinity of the root systems. Using these about twice a year supposedly supplies enough iron, but I have not yet tried this.

Try using a blend of laterite and flourite. Both have their advantages. Flourite tends to be high in Potassium and other elementes utilized by plants. Laterite is higher in Iron, which is an absolutely vital element in the synthesis of chlorophyll. If you use just flourite, I would recommend using the above mentioned laterite additives (they come in the form of 1 inch balls of claylike consistency) to supplement your gravel bed with iron.

Lastly, bright light or fast growing plants (like Amazon Swords) will use nutrients faster than slower growing or low light plants. If you have fast growers, expect to replace the substrate in about two years. If you grow things like Anubias and Cryptocorinae (slower growth), you might get three or even four years out of it.

Good luck!
- Wil

[CrazieEddie]

Cool!

Thanks for the info :)

[phoenixshade]

Check out this link...

Discus Page Holland (Bonsai & Planted Tanks) (http://article.discusnews.com/cat-04/bonsai.shtml)

I haven't tried this yet, but it looks pretty good to me!! I'll be trying this in my discus tank. (In place of "clay", I will use a laterite/flourite mixture.)