1. Stop using the "Algae Guard"; it's not helping, and it is using up chlorine.

2. Read the Best Guess page linked in my signature block -- it will explain what chlorine levels you need, and why.

3. If you want to make an investment in making your pool algae resistant, you can do this at the same time you are working on the controlling the algae. 60 ppm of borates seem to make a pool significantly more algae resistant, though it's not clear why. In your case, that means about around (20) boxes of borax and 5 or 6 gallons of 31% muriatic acid. The most conservative way to do it is to add 4 boxes of borax -- slowly through the skimmer with the pump running -- then 1 gallon of muriatic acid to the pool, and then circulate the pool for 4 hours, test, and adjust pH to 7.2 - 7.8, and repeat. Slow down on the last 4 boxes of borax, so you can dial in your pH. You may end up with a bit of borax OR acid left over.

4. Get a cheap OTO/phenol red (yellow / red drops) and use it side by side with the K2006, so you can get the hang of recognizing the OTO color that corresponds to an adequate chlorine level in your pool with CYA=70 ppm. That way, you won't use up the test reagents in the K2006 so fast.