Narrow leaf sword

[Fiori]

The title says it all really - my swords are getting brown spots with yellow edges on them - I've got sand substrate, CO2, root fertilisers as well as liquid and about 2.7 WPG lighting. I tried to work out if there was a mineral deficiency, but the tables on the web were a bit confusing (I am seeing yellow spots when my eyes are closed now ) and I just ended up being completely gaga. So.... can anyone help me out here and tell me what the problem is?

Cheers

 

[kenneth_kpe]

http/www.aquabotanic.com/diagnose.htm

i like to refer to this chart when i try to trace defficiency problems, but maybe just maybe you just started dosing recently and the plant is yet to show recovery ?

 

[Fiori]

Thanks for that table - its much clearer than some of the ones I've seen. I have extremely soft water - GH is only 2, KH 1, so I suspect they are missing some dissolved minerals lacking in my soft water. Can you buy specific mineral supplements for aquatic plants?