My investment plan. Need someone to review it

[Hon Ching Lai]

I am in Seattle area. Here's what I have. 500k in cash, a paid off single family rental property that I plan to take out a HELOC of , est 700k limit. I plan to use the cash I have for down payments to buy multifamily units. Meanwhile using the money from heloc as my short term loan. Making sure I buy properties at ~75% of the ARV. After repairs and putting tenants in, I'll refinance and hopefully paid off my HELOC and then do it all over again. Can anyone tell me if this is a good idea, or areas for improvements