hi aswarren,
in order to clear your pool, you are going to have to raise FC to 40% of whatever your CYA level is and you are going to have to keep the FC at that level until the water is perfectly clear. Thats the way to kill off the algae once and for all.
If CYA is 100, then your FC level will need to be 40! Man that is a LOT of chlorine to be adding every day and maintaining. Maybe even for weeks to finally get it crystal clear and algae free.
Here is the real issue though, All CYA test, only can measure up to 100. If the reading is 100, then the CYA may actually be well above that number. If you cant measure the CYA accurately, then there is no way to know how much chlorine to add in order to get that 40% mark.
To add, the only FC test that can measure up to 40 or higher, is the FAS-DPD which is contained in the TF 100 test kit.
Draining 30% of your water may help, but at a minimum that would get your CYA down to 70, and FC requirement would then be 28.
Still, thats a lot of bleach.
I dont know how much your water costs in St Louis, but it will likely be less to refill at least 50% of the pool than the amount of bleach your going to need will cost if your CYA even gets to 70.
Given these considerations, a test kit in the short term along with a larger water change is going to be less expensive than tossing massive amounts of chlorine into the pool without any reliable way to test the levels. You may well spend a few hundered more with no improvement unless you can measure the water parameters reliably.
I know it seems like an expense, but its really an investment and at the end of the day, will save you a lot of sweat, tears, heartache and money.
Im not trying to sell you a test kit, but just letting you know what you're in for if you dont have one.
PS 1
TDS has nothing to do with your algae problem. 1100 is not even considered to be high by TFP standards.
PS 2
Algaecide is not effective at killing an algae bloom. It's somewhat of a measure to prevent it from happening, but considering the cost of the stuff along with the copper it adds to your water, it ain't worth it. Using straight liquid chlorine is a much more effective and less costly way to prevent algae.