How to grow with a HELOC?

[Sadierose Saucier]

Hi everyone!
Long story short, my fiancé and I house hacked a 3 family for a few years. We bought another duplex to house hack this past February, keeping our first 3 family.
We are cash flowing $500/mo at the first 3 family now that we are moved out and when we move out of the duplex we will cash flow $500/mo from that one as well. 
We have 2 open HELOC's, one on each property for $30,000. We have an FHA loan available to us that we would like to buy the next property with.
To use the BRRRR method and use the HELOC to purchase more properties, how do you continue to cash flow well when you now have another mortgage to pay?
Also, we are having a hard time in this market using an FHA loan.

We just feel stuck. Our goal is at least 2 properties a year. Thank you for an recommendations or advice.