We recently moved into a house that has a pool and according to the previous owner, was never drained since he moved in - they moved into the house in 2004. His weekly maintenance did not include testing, rather he added 3 trichlor pucks, 2 cups of muriatic acid, 1 pound of powder trichlor shock, and 1 cup of phosfree. 
As you can imagine, the CYA levels are off the charts. I spoke to my friend who works for a pool company who said that it is too hot to drain the pool and we should wait until it doesn't go above 85 degrees. I initially took it to Leslies to test when I first moved in and there was no chlorine. I didn't know much about pools at the time, but was confused because I shocked it the night before. After doing research, I realized that this is due to the CYA levels. I bought a taylor test kit (non FAS-DPD k-2005). I tested the levels and CYA was well over 100. PH was almost 10. I went on the pool calculator and with my levels it told me I needed to drain 85% of the pool. It also told me how much acid and bleach to add. I know there is not much that can be done for a pool with such a high level of CYA, but now I am getting algae. As soon as it appears I brush the pool and add bleach.
My question is...can I do anything in the interim to get enough chlorine in my pool to kill the algae without adding too much that will damage anything.
Second, is it possible to purchase the FAS-DPD test alone as I already have all other necessary tests?
Third, I cannot get the PH down. I have added half a gallon of acid at one time and it hardly puts a dent on the PH levels.
The pool is approximately 16,000 - 18,000 gallons and pebble tech.
As you can imagine, the CYA levels are off the charts. I spoke to my friend who works for a pool company who said that it is too hot to drain the pool and we should wait until it doesn't go above 85 degrees. I initially took it to Leslies to test when I first moved in and there was no chlorine. I didn't know much about pools at the time, but was confused because I shocked it the night before. After doing research, I realized that this is due to the CYA levels. I bought a taylor test kit (non FAS-DPD k-2005). I tested the levels and CYA was well over 100. PH was almost 10. I went on the pool calculator and with my levels it told me I needed to drain 85% of the pool. It also told me how much acid and bleach to add. I know there is not much that can be done for a pool with such a high level of CYA, but now I am getting algae. As soon as it appears I brush the pool and add bleach.My question is...can I do anything in the interim to get enough chlorine in my pool to kill the algae without adding too much that will damage anything.
Second, is it possible to purchase the FAS-DPD test alone as I already have all other necessary tests?
Third, I cannot get the PH down. I have added half a gallon of acid at one time and it hardly puts a dent on the PH levels.
The pool is approximately 16,000 - 18,000 gallons and pebble tech.
