Let's say I want to keep the FC level my 500 US gallon spa in the 4 - 6 ppm range when I'm away for a number of days and my CYA level is in the 30 - 40 range. In this scenario, the spa will be covered the whole time (no sunlight) and no one will be bathing in it. The circulation pump will be circulating 24/7. At what rate should I expect the FC to decay in the water?
The reason I ask is that I'm contemplating installing a small chlorine bleach dosing pump that I can control remotely and with the same setup turn the jet pumps on and off for a short burst to mix the water after the bleach has been injected. My plan is to inject the bleach into the cirulation line just after the circ pump and heater and then a minute or two after the bleach has finished being dosed in and has had time to make it's way into the tub, fire up the jet pumps for 2 or 3 minutes and then shut them down. The contoller for the system will be wifi enabled and if it all works as planned, I'll be able to program and control both the dosing pump and my jet pumps remotely over the internet from my smartphone or tablet. If I can make this work, I should be able to do it all for less than $60 USD. Maybe even less than $50 USD.
With this system, I can have it set to inject chlorine in small amounts a few times a day (at regular intervals) or inject larger amounts (but still not that much) once a day or every two days or whatever I need in order to keep the FC level steady within the target range. As such, I'll need to know the rate at which the chlorine is likely to decay under the above described conditions since I don't know how I'd be able to monitor FC levels (i.e. use a FC probe/sensor of some type) and stay at such a low budget level.
Is there an equation I can use for this? Will the FC attenuation rate be temperature dependent allowing me to reduce the decay rate by turning down the tub temp?
The reason I ask is that I'm contemplating installing a small chlorine bleach dosing pump that I can control remotely and with the same setup turn the jet pumps on and off for a short burst to mix the water after the bleach has been injected. My plan is to inject the bleach into the cirulation line just after the circ pump and heater and then a minute or two after the bleach has finished being dosed in and has had time to make it's way into the tub, fire up the jet pumps for 2 or 3 minutes and then shut them down. The contoller for the system will be wifi enabled and if it all works as planned, I'll be able to program and control both the dosing pump and my jet pumps remotely over the internet from my smartphone or tablet. If I can make this work, I should be able to do it all for less than $60 USD. Maybe even less than $50 USD.
With this system, I can have it set to inject chlorine in small amounts a few times a day (at regular intervals) or inject larger amounts (but still not that much) once a day or every two days or whatever I need in order to keep the FC level steady within the target range. As such, I'll need to know the rate at which the chlorine is likely to decay under the above described conditions since I don't know how I'd be able to monitor FC levels (i.e. use a FC probe/sensor of some type) and stay at such a low budget level.
Is there an equation I can use for this? Will the FC attenuation rate be temperature dependent allowing me to reduce the decay rate by turning down the tub temp?
