Hi Tom,
your rec. for Mg supply reads 1/4 teaspoon ~ 1,67g MgSO4/week/20g. This rounds up to 22ppm MgSO4 or 2,2ppm of pure Mg.
From what I've observed I say this: With hornworth in my tank (a real fast grower) introducing 3,5ppm of pure Mg/week did not support growth of Rot. rotundifolia in the long run. Other data: KH 2, NO3 5-10ppm, PO4 0,4ppm, lighting 2,7 watts/g, press. CO2 (mist).
After months of introducing 3,5ppm Mg/week (other param's as stable as possible) I measured only 2,2ppm Mg (GH 2,3, Ca 12,4ppm). Supposedly hornworth has been taking up a considerable amount of Mg. Rot. rotundifolia resumed growth from only 1cm/week to normal rates (>5cm/week) after I added one extra ppm of Mg (MgSO4 and MgCl) during a 3 day period and keeping Mg levels there (4,25ppm) after wc's. Sounds weird to me as only 1ppm Mg makes up for such a difference. From what the plants are telling me I'd rec. keeping Mg round about 4ppm min. (might be related to KH etc.). From my observations I derive also that there is a distinct difference in Mg demand. Hornworth does not need as much Mg as R. rotundifolia.
Please take these findings with great caution since I have NOT repeated the test nor can I exclude measurement errors. Just my 2 cents since we don't know much about min/max amounts of Mg.
Regards,
Detlef
your rec. for Mg supply reads 1/4 teaspoon ~ 1,67g MgSO4/week/20g. This rounds up to 22ppm MgSO4 or 2,2ppm of pure Mg.
From what I've observed I say this: With hornworth in my tank (a real fast grower) introducing 3,5ppm of pure Mg/week did not support growth of Rot. rotundifolia in the long run. Other data: KH 2, NO3 5-10ppm, PO4 0,4ppm, lighting 2,7 watts/g, press. CO2 (mist).
After months of introducing 3,5ppm Mg/week (other param's as stable as possible) I measured only 2,2ppm Mg (GH 2,3, Ca 12,4ppm). Supposedly hornworth has been taking up a considerable amount of Mg. Rot. rotundifolia resumed growth from only 1cm/week to normal rates (>5cm/week) after I added one extra ppm of Mg (MgSO4 and MgCl) during a 3 day period and keeping Mg levels there (4,25ppm) after wc's. Sounds weird to me as only 1ppm Mg makes up for such a difference. From what the plants are telling me I'd rec. keeping Mg round about 4ppm min. (might be related to KH etc.). From my observations I derive also that there is a distinct difference in Mg demand. Hornworth does not need as much Mg as R. rotundifolia.
Please take these findings with great caution since I have NOT repeated the test nor can I exclude measurement errors. Just my 2 cents since we don't know much about min/max amounts of Mg.
Regards,
Detlef