If I understand you correctly, you have about 15 - 20 # of CYA on hand? If so, once your filter can run 2 - 3 days between backwashes, begin adding it slowly, via the skimmer. Add 3 - 5 lbs just AFTER each backwash. It's slow to dissolve, and will have to sit on your filter.

Once you do this, do not add ANY other chemicals via the skimmer, except bleach or borax. While there's CYA on top of the filter sand, add everything else directly to the pool . . . of course, there's really not much else you should be adding.

Check your CYA after backwashing, but before adding the next dose. You probably want to get to 80 ppm before your turn your SWCG on. Add bleach each evening, as needed, till you are ready to turn it on.

If you want your pool to 'sparkle' there's persistent evidence that 50+ ppm of borates will make a significant contribution to this. For your pool, that means about 12 boxes of borax, plus about 4 gallons of muriatic acid to lower the pH. If you lower your pH FIRST, and keep it low, you'll also lower your CARBONATE alkalinity at the same time, that you are increasing alkalinity from borates and cyanurates. The combination of low carbonate alkalinity and borates will reduce your pool's liklihood of getting algae. To add borates that way, add 1/2 of a bottle of muriatic at a time, till your pH goes below 7.0. Then, add a box of borax -- slowly through the skimmer -- each day, till it goes above 7.2 again. Then, add borax again, and so on, till all your borax is consumed. Once that's done, add enough additional borax to get your pH to 7.4 - 7.8. If you arrange your returns so they ruffle the surface, or even splash, you increase removal of carbonate alkalinity.

Now, this also means that you should NOT use the bicarbonate or sodium carbonate you have, since those increase carbonate alkalinity.

Just to be clear, TA = Total alkalinity = alkalinity from carbonates, borates, cyanurates, and possibly phosphates. Carbonate alkalinity refers exclusively to alkalinity from baking soda, washing soda, or carbon dioxide.

And read this post: http://www.poolforum.com/pf2/showthread.php?13111 about using muriatic acid safely.