Hi all,

It says dissolve 300 grms "solufeed sodium free TEC multi micro nutrient fertilizer" in 100 litres of water.

It says the stock solution will contain

1 Boron 32 ppm

2 Copper 7 ppm

3 Iron 252 ppm

,I have a q does 0.2 ppm = 200 ppm or 2 ppm sorry I get lost in the math.

It is really easy to get lost in the powers of ten. I'll start by ignoring the stock solution and dilutions and just go with adding the dry powder to the tank.

If you add

**3 grams to 100 litres** of tank water, you've divided

**300 by 100**, so then you need to divide the

**252 by 100 as well,** and you've added

**2.52 ppm Fe**.

If you add 0.3g (

**3/10**) of "solufeed sodium free TEC multi micro nutrient fertilizer" to 100 litres you have 0.25 (

**2.5/10**) ppm Fe.

Both

@Oldguy and I don't like working with very small weights of fertiliser, so rather than trying to accurately weight out 0.3g we'd weigh out a larger weight and then dilute that solution.

Working with powers of ten is always easiest. So if you dissolved 3g of "solufeed sodium free TEC multi micro nutrient fertilizer" in water, and make that up to a litre (1000 mL), you could add 100 mL of that solution (to your 100 litres aquarium) to get 0.25ppm Fe.

Because your 3g in 1000 mL solution is dilute, you can also assume that 1 mL of solution weighs 1 gram, and you use weight, rather than volume, to get the litre (1 kg) and 100 mL (100 g) volumes.

cheers Darrel