Getting ready to open 40k gal pool AKA "the Swamp"

[KJohnston]

Hi! I'm new and so glad to have found this forum! We are getting ready to open our pool, it has no cover we just plugged the pipes and let it sit all winter. It is very brown/green with more dirt than leaves on the bottom. We have a SWCG but the last few years it has not been working so we have just been using bleach. Last year we had a terrible time with algae but no one told me to shock it and keep it there, so glad to have read that here! So, my question is, where do I start? Obviously we'll take the plugs out, fill it up to normal then turn it on. I have just purchased the Taylor k-2006 kit and 16 boxes of borax (just to be ready!). Our pool is concrete/plaster it is free form and approx. 40,000 gal. We have a Sta-Rite filter and a Hayward pump. How much LC am I going to need to start it up? Will I need to test first to see if we have any CYA? I prefer the LC because we got some calcium spots with the other. I finally have hope that we can get rid of the algae once and for all with the help of this forum.