Thanks Zozo, Yes it has grown in rather well, a substrate aged over a decade may have it's advantages even if hard to replicate.
However before I refreshed this tank there were some very well established Echinodorus / Sword Plants and all I did was trim them off at substrate level leaving what would surely be a highly extensive root network still in the substrate to decompose and fertilise the new plants. That seems to have worked remarkably well because fert wise I'm only adding two pumps of Tropica Specialised on Sunday plus one pump on Wednesday.
However before I refreshed this tank there were some very well established Echinodorus / Sword Plants and all I did was trim them off at substrate level leaving what would surely be a highly extensive root network still in the substrate to decompose and fertilise the new plants. That seems to have worked remarkably well because fert wise I'm only adding two pumps of Tropica Specialised on Sunday plus one pump on Wednesday.