I've decided to start putting together a backup plan for the LQ in case I can't get enough chlorine into the pool with it. Right now it's running wide open with a 3/8" line and I'm holding 1ppm steady in a 40K gallon pool. I want the option to eventually use a chemical controller for PH (and maybe ORP since I don't have a SWG), which means the dosage will need to happen in bursts, vs. running continuously all the time (right?). In the mean time, I can use relays on my Aqualink to act as a timer for the pumps when the circulation system is on (which is 24/7 at about 25-30GPM), to run the pumps for shorter periods of time at higher flow rates.
Rate range - Chlorine
For the low filtration flow rate I want to run to conserve power, our puck system has never worked, and I still have not been able to get TC to where I want it with the LQ. I don't have a good guess at what range of dosage I need each day. I know it will change depending on a lot of factors, especially temp. We have a UV system that will also burn off some of the Chlorine, and hopefully will let me run 1-1.5ppm of chlorine.
For the sake of argument lets say I use 2 gallons per week. A high pressure 22GPD unit will let me dose that much amortized over each day in a 20min/day block running at it's highest output rate, or about 5 hours running at the slowest speed.
Should I be prepared to run more than 2 gallons per week? Is a burst of chlorine in a 20min block each day the right way to go, or to apply over a longer period? Will that work with an ORP control system? I looked at the Jandy C1900, and as best I can tell it like the dosage to be in the 10min or less range, or continuously.
Rate range - Acid
My TA is high (I think due to Austin water and our pebble tec, new pool), so I've been adding dry acid once a week - about 60 volume oz, which is about the same as muriatic acid.
So given that, with the same pump 22GPD, the dosage could happen in 5min each day spread across the week, or 2 hours at the lowest speed.
I'm assuming I do not need a high pressure unit if it's injecting after the filter/heater? Correct? The units seem to come in low pressure 0-25psi and high pressure 25-100psi.
Pump Choices (Stenner, all are $250):
45MHP22 25-100psi, 1.1 to 22 GPD
85MHP40 25-100psi, 2 to 40GPD
45M3 0-25PSI, 1.1 to 22GPD
45M4 0-25psi, 1.7-35GPD
85M3 0-25Psi, 2-40GPD
(there are units that have lower flow rates)
Any advice would be much appreciated.