$s_1 \frac{dh_1}{dt}=q_1 -\alpha_1 \sqrt{h_1-h_2}$
$s_2 \frac{dh_2}{dt}=\alpha_1 \sqrt{h_1-h_2}-\alpha_2\sqrt{h_2}$
$\alpha_1=0.0000208, s1=0.002025m^2, 0.0000163, s2=0.002025m^2$
However, you did not provide range for $q_1, h_1,h_2$ and maximum height for both tank.