With all respect to Chuck, I now use this:
http://www.aquaticplantcentral.com/forum/fertilator.php
I test PO4 and NO3 after the water change and dose accordingly. If NO3 doesn't decline during the week, I'll add K2SO4. I watch the new growth on h. difformis as an indiactor for Fe (iron) but it's looking like a twice-weekly dose of CSM+B at .1 ppm Fe is working.
TW
http://www.aquaticplantcentral.com/forum/fertilator.php
I test PO4 and NO3 after the water change and dose accordingly. If NO3 doesn't decline during the week, I'll add K2SO4. I watch the new growth on h. difformis as an indiactor for Fe (iron) but it's looking like a twice-weekly dose of CSM+B at .1 ppm Fe is working.
TW
