i saw your other thread about moving to 2.5wpg. again, you'll need pressurised co2 and a good dosing regime, i would encourgae anyone to go ei dosing at 1.7wpg or above
the swords will like the sand so that's good, put the root tabs in just now, but if you switch to ei dosing you may not need to worry do much about it
would also suggest that if you get pressurised co2 place the output under your tiger lotus to help keep it in the tank for longer before hitting the surface. i also investied in a solenoid so my co2 is only on with my lights. these two things save me $$$ on co2 costs.
good luck, sounds interesting, please keep us updated when you upgrade your lighting
i remember its a diy lighting, i'd be really interested to see what you doing, can you do a blog on this or something?