Plant Root Tabs And Trace Element Additives

[Fillet 'O' Fish]

Can anyone recomend good plant food root tabs (as I have only a gravel substrate), and also essential trace elements to add etc?

I dont want to mess up the water chemistry in my community tank as it is good and settled at the moment.

I have just started to use pressurised CO2 and have noticed the results already after one week !
But the leaves are slightly brown in places and probably lacking in Iron etc.

Any suggestions / recmendations ?

 

[zig]

What are the stats of the tank, how much light are you using and any test kit results etc? depending on that you may need more than just trace elements (but there again you may not )