this is totally doable with blynk, in fact it is a lot like how I started. I had an lcd display, etc…when I found blynk, i ditched all that and used the blynk app. I will try and have a look at your code when i get some time, as I will be adding this same functionality to my project anyway, in the interim, see if you can make sense of some of the things I have done…
basically just put the control code into functions (example: void PumpControl() ) then call the functions with the SimpleTimer routine.