Just add the CYA separately and switch to bleach. Since you are fighting algae and will most likely be backwashing frequently, I wouldn't put the CYA into the skimmer but instead put it in an old sock and hang it in front of a return jet. Give the sock a squeeze every now and then to help it dissolve faster. Since you've been using dichlor for a but, I'd aim a little low for the CYA to account for the amount that is already in the water but just not measurable yet. Probably aiming for about a 30ppm dose (4 lbs). would be good. Then, after a week, test CYA and see where you are. You can then decide whether you need to add more or not. Quit using dichlor shock or trichlor pucks. Just use bleach.

To clear the algae, try and keep the chlorine at 15ppm. In an 18K gallon pool, each gallon (4 quarts) of 6% bleach will add about 3.3ppm of cl. Test as many times per day as you can (no such thing as too often) and each time, add enough bleach to get back to 15. Run the pump 24/7 and backwash any time the pressure rises 5-10psi over clean filter pressure. Continue to sustain the high cl until you can go from sundown one evening until within 2 hours of sunup the next morning without losing more than 1ppm of cl and your CC is no greater than 0.5. At that point, I'd suggest running the high cl levels for one additional day for added insurance and then let the cl drift down and keep it in the proper range based on your CYA. (See the Best Guess Table in my signature below.)

Have you added the DE yet? If not, I'd wait until the algae is dead and you aren't having to backwash so frequently as backwashing throws the DE out.

With the K-2006 kit, always use the 10ml sample instead of the 25ml sample to conserve your reagents. The 0.5 accuracy is sufficient.

One last request. To make it easier for us to help you, we are encouraging people to create a signature line with the specs of their pool set up in it. You can do this by clicking on settings in the upper right hand corner of the homepage. We would like you to put the following things in there: type of pool, volume, type of filter, size of pump, and the fact that you have a K-2006. That will help us to be able to answer posts more quickly especially when threads get long. It is time-consuming to have to continually scroll back through a thread to look for basic information. Thanks.