Poor Man's Dupla Drops
After much experimentation, I've concocted my own version of Dupla Drops.
The recipe is:
1 tbsp (15ml) Chelated Trace Element Mix (7% Fe)
1.5 tsp (7.5ml) K2SO4
1 tsp (5ml) KNO3
180ml distilled H2O (mix in the trace elements first)
For my 135g tank I add about 7.5ml of this mixture every day, except
when I do a 25% water change, in which case I add 15ml. This keeps
the Fe at about 0.25ppm and the nitrates around 10ppm. My cost for
this mix is under 3 cents (Canadian) a day. All the ingredients were
purchased at the local hydroponics shop.
The mixture can be tuned by adding more or less KNO3. Determine how
much of the mixture you need to add daily to get your target Fe level,
then check the nitrate levels. If nitrates are too high you can
replace the 1 tsp KNO3 with another 1/2 tsp K2SO4. If they're too
low, just add more KNO3. I've somewhat arbitrarily set K to be
roughly 10 times the Fe concentration.
My trace element mix has no Mg. If your water doesn't supply enough
Mg you can add some MgSO4 (Epsom Salts).
Kevin Conlin kcconlin at cae_ca "We're Canadians. We HAVE to be polite"