I have installed a Stenner MP45 pump into my system to dose chlorine. It has a flowrate of 35 GPD, or 3.11 oz/minute. Looks like about 27 minutes will give me the dose that I want. I used open sprinkler at my old house, so I was already familiar with it, and just installed it into my new house (this one has a pool.) I have lived here a year and the previous owner used pucks. The CYA was more than 250 when I moved in. Over the last year, I had ceased using pucks and instead Chlorinated daily with liquid bleach from Aldi's, and water my lawn with pool water as part of my CYA elimination program. Over the last year, I have driven my CYA level down to around 40 or so. I am happy with that aspect and plan to continue with liquid bleach, spring summer and fall. Using the Stenner will allow me to draw from a 5 gallon tank and dose it automatically.
For my timer, I will use the Opensprinkler controller. Its a weather aware, arduino based system for controlling irrigation sprinklers and since it is open source based, the developers and others are very helpful in adapting the program, giving advice, etc... I already was using the first 8 zones for my sprinkler, so I bought an expansion board. I will use the first extra zone to control my Stenner and maybe the next one after that to do an automatic water addition to the pool each day. With open sprinkler, I can control the run time of the pump each day in minutes, and I can do it from my phone. My plan is to have it kick on at 8pm each night and run for 27 minutes. After a few days, I'll measure the chlorine and adjust the run time up or down. I ahve a VFD pump that runs 24hrs a day to circulate, so I am not real worried about synchronizing chlorine and water pumping in my system.
It is getting hard wired using a 24Vac relay. I'll post some pics soon. Maybe in the future, I can have it adjust the Chlorine input slightly based on temp and clouds. The sprinkler system already can increase and decrease the sprinkler run time based on weather, so I might be able to get a routine added for pool chlorination. In any case, being able to adjust my daily Chlorine dose from my cell phone will be really cool.