I am having a problem with writing equations using `dmath` and `dgroup` in my article. the packages I am using are 

```
\documentclass[a4paper 12pt] {article}
\usepackage{breqn}

```

The codes I am writing are - 

```
\begin{dgroup}
\begin{dmath}
v_f = k_f C_O(0,t) = \frac{i_c}{nFA}
\end{dmath}
\begin{dmath}
v_b = k_b C_R(0,t) = \frac{i_a}{nFA}
\end{dmath}
\label{eq14}
\end{dgroup}

```

The problem is that it has two equal signs in the same line of equation. with this settings I am getting the results okay but after the two lines of equations, LaTeX puts a big gap before I start my text again. When I use `equation` in place of `dmath`, the big space after the two lines of equations are gone but the equations are not at two lines any more. It puts the `= \frac{i_c}{nFA}` part into the next line, which I don't want. Can anyone please help me with a solution?