Chlorine Stability

[hamop78]

Richard,
The experiment is on. I got the peristaltic pump hooked up today and calibrated the flow rate using pool water.

At this time I am injecting a 50/50 mix of bleach and pool water at the rate of 56 oz/hour. I tested the mixture and it came out to 3.4 ppm (FAS-DPD) using the .1ml/1L well water method you helped me with.

After 4 hours, the free chlorine had gone up 2.2 ppm so I may need to back the rate off a bit. Loss to the sun before adding any chlorine was 1.8 ppm in a 4 hour period this morning. It was not very sunny this afternoon so……..

Since I used pool water to dilute the Bleach, am I correct that this might help stabilize the mixture. Pool water CYA is ~45ppm. The half-life is a whole lot longer than the reservoir supply will last. I have a 6 gallon bucket covered with white EPDM roofing material to keep out the UV.

The better half (Jakebear) will be testing during the day tomorrow to make sure things do not run amuck.

I'll keep y'all posted.

[chem geek]

Since I used pool water to dilute the Bleach, am I correct that this might help stabilize the mixture. Pool water CYA is ~45ppm.

Yes you are correct, the CYA will help prevent the chlorine in your pump source bucket from breaking down from sunlight, just in case any got in (it sounds like it won't).

[fcfrey]

Sounds like the best of both worlds ---- No pucks and semi-automatic chlorine addition just like the erosion feeders.

Where did you get the pump and SWAG cost of the system?

[hamop78]

fcfrey,
This is an experiment so it's a bit early to tell. The way I figure, it should be more accurate than the erosion chlorinator because the technology is better and close to the same price. The pump was about $200. from Grainger. other costs were an old 6 gal bucket with lid, some scrap rubber roof material, 6 ft of wire and a plug --- Oh yes --- 2 milk crates (for now to get the pump off the ground).

Installation required drilling and tapping for a 1/4" NPT injection port that came with the pump. I placed it so it was the last piece of pipe before the return jets so it doesn't go through the solar system.

Calibration of the pump is pretty tedious since you have to measure the liquid and time how long it takes to pump it at a certain RPM. I'm building data and so far I think it pumps .07 oz per half cycle (2 lobes on the pump) so if you know the RPM you can determine the feed rate (RPM X .07 X 2). I need some more time to verify the feed rates.

Like I said in an earlier post. I test the mixture in the feed reservoir by mixing .1ml of the solution in 1L of non-chlorinated water then run an FAS-DPD test on it to determine the chlorine percentage of solution being injected. Knowing all of that and the run time I should be able to calculate the outcome before testing. The next obvious step is to put a controller (Many $$$$) on the system but for now, it is the better half twisting the knob.