My dosage calculations

[BT]

Hi, I am trying to understand more of the calculations involved in having the right nutrient dosage, and in this case, I am specifically interested in Fe. I have worked out 2 sets of calculations, please help me verify if my concept, or chemistry calculations are correct (kinda make me feel like I am back in JC)

My tank is 4ftx2ftx20" height. Taking into account the depth of substrate and water level, my tank volume (water only) is approximately 280l.

i) Dosing with TMG - stated 0.07% Fe
Stated on the TMG container: 100ml = 104g
For my usual dosage is 35ml of TMG = 35ml x (104g/100ml)
= 36.4g (weight)
Weight of Fe in 36.4g of TMG = (0.07%/100%)x 36.4g
= 0.02548g
For a 280l tank,
Concentration of Fe = (0.02548g/280l)
= 0.000091g/l
= 0.094mg/l => 0.094PPM
Is this way of calculation correct?

ii) Using Dr Mallick's Rexolin D11, which contains 11% chelated Fe in powder form
Assuming I use a spoon that yields 1.5g of powder,
Weight of Fe present = 1.5g x (11%/100%)
= 0.165g
Dissolving this in my 280l tank,
Concentration of Fe would be = (0.165g/280l)
= 0.0005892g/l
= 0.5892mg/l => 0.5892PPM
Is the calculation correct?

Also, is 0.5ppm of Fe a good level to have?

Cheers,
Bryan

[aquaticquotient]

Wow....too profound for me even! Next better player help him pls! Moderators coming, hang on there!

[bclee]

Basically, it is correct.

Only one thing... in liquid solution, the contents given in % usually means g/l. You do not have to convert l to g for calcutions.

Aquaticquotient, I hope the mods do not come after you for using the forum name.

BC

[theodore]

0.5ppm of Fe is a bit on the high side IMO but still within the recommended range suggested by Tom (Read this).

Personally, I dose 0.2ppm of Fe per week and stick some Iron tablets near my red plants every few months (courtesy of the Blood Bank). I used to see spot algae problem with my tank when I was dosing 0.4ppm of Fe.