I've owned a pool previously (at a different house, on city water), and am familiar with water chemistry - but I have a problem that is stumping me.
Last week, I had a new AquaRest AR-400 premium (ozone) tub delivered. After I filled it the first time, I added about 16ppm of dichlor and tested the next day. Free chlorine was around 2ppm, and combined chlorine was around 5ppm. So I shocked the tub to 90ppm using dichlor, left it for a day, and then drained it... thinking the tub may have been dirty. (Although it was new, there was water seeping out of the jets when it was delivered. I assume it was tested at the factory, as it didn't look like it had been used and returned.)
On the second fill, I focused first on adding acid. I have a well, and my starting TA is above 400. I spent 3 days adding about 18oz of dry acid to the tub, maintaining a steady 3-4ppm. After getting the TA to 120, I tested again - hoping that having enough free chlorine with a "closer to correct" TA and pH would mean less chlormaines - but chloramines were still around 5pm. So I drained it again.
With desperation, on my third try, I added enough dichlor to bring FC to around 20ppm, and then very aggressively added enough acid, in 1 oz drops, to get the TA to 120 in one day (same day as the fill). Then, in 6 gallon buckets, I pre-dissolved enough cal hypo to shock the tub up to 50ppm. (I have a softener, and added enough hard water and soft water mix to bring my CH to about what I'd need to use the cal hypo, instead of dichlor which adds unwanted CYA). I let the cal hypo do its thing around dusk, running the pump for an hour. Then I left it in the sun the next day to bring FC back down to around 3ppm.
Then, after testing, my CC was still around 5ppm. The only noticeable change after shocking with cal hypo was the smell. When you turn on the jets, it doesn't smell like chlorine anymore. Maybe it smells like amonia? It's a smell I'm not accustomed to. I am guessing the smell is related to DBP's generated from superchlorination.
So... my leading theories are that there's a dead animal stuck in the lines someplace. The pump and the jets seem to work okay - so if there is one, it's not obvious. (the filter is new, and i've cleaned it with a hose using soft water on each fill.) The other theory is that there's something in my well water that's producing chlormaines that are highly resistant to oxidation. It's not unheard of for wells in my area to have nitrates in them. I've read that organic chloramines are extremely difficult to break down, and I think nitrates would produce organic chloramines (?). The prescription I've seen for this is draining and re-filling with fresh water, but if the contaminats are coming from "fresh water", that won't help.
The tub I have has an ozonator. It's producing bubbles, so I assume it's working.
My thoughts are: 1) try a non-chlorine shock, like MPS. But, my CC are so high that it would be an exceptionally high dosage of that type of shock. I don't know whether that's a great idea. I absolutely do not want to end up in a situation where I have to drain the tub again, if it can be avoided. I can't tell you how time consuming it is to dump 18oz of acid into a 190 gallon tub. It literally makes me want to cry to think about doing it a 4th time in 10 days.
The other idea is to get an aquarium UV lamp off Amazon. That wouldn't hurt anything, but I'm not sure whether it'll help. I have a whole-home UV disinfection system for my well water, which sits just past the water softener. So all the soft water entering the tub has already been UV treated... but, on the other hand, the wholke-home UV system wouldn't have had any action on potential nitrates - since they weren't bound by chlorine when they passed the UV bulb prior to entering the tub. (All of our drinking water goes through point-of-use RO filtration inside the house, so using RO water to fill the tub isn't practical.)
So.... apologies for the length of my post... but any thoughts? I am willing to try anything at this point!
Last week, I had a new AquaRest AR-400 premium (ozone) tub delivered. After I filled it the first time, I added about 16ppm of dichlor and tested the next day. Free chlorine was around 2ppm, and combined chlorine was around 5ppm. So I shocked the tub to 90ppm using dichlor, left it for a day, and then drained it... thinking the tub may have been dirty. (Although it was new, there was water seeping out of the jets when it was delivered. I assume it was tested at the factory, as it didn't look like it had been used and returned.)
On the second fill, I focused first on adding acid. I have a well, and my starting TA is above 400. I spent 3 days adding about 18oz of dry acid to the tub, maintaining a steady 3-4ppm. After getting the TA to 120, I tested again - hoping that having enough free chlorine with a "closer to correct" TA and pH would mean less chlormaines - but chloramines were still around 5pm. So I drained it again.
With desperation, on my third try, I added enough dichlor to bring FC to around 20ppm, and then very aggressively added enough acid, in 1 oz drops, to get the TA to 120 in one day (same day as the fill). Then, in 6 gallon buckets, I pre-dissolved enough cal hypo to shock the tub up to 50ppm. (I have a softener, and added enough hard water and soft water mix to bring my CH to about what I'd need to use the cal hypo, instead of dichlor which adds unwanted CYA). I let the cal hypo do its thing around dusk, running the pump for an hour. Then I left it in the sun the next day to bring FC back down to around 3ppm.
Then, after testing, my CC was still around 5ppm. The only noticeable change after shocking with cal hypo was the smell. When you turn on the jets, it doesn't smell like chlorine anymore. Maybe it smells like amonia? It's a smell I'm not accustomed to. I am guessing the smell is related to DBP's generated from superchlorination.
So... my leading theories are that there's a dead animal stuck in the lines someplace. The pump and the jets seem to work okay - so if there is one, it's not obvious. (the filter is new, and i've cleaned it with a hose using soft water on each fill.) The other theory is that there's something in my well water that's producing chlormaines that are highly resistant to oxidation. It's not unheard of for wells in my area to have nitrates in them. I've read that organic chloramines are extremely difficult to break down, and I think nitrates would produce organic chloramines (?). The prescription I've seen for this is draining and re-filling with fresh water, but if the contaminats are coming from "fresh water", that won't help.
The tub I have has an ozonator. It's producing bubbles, so I assume it's working.
My thoughts are: 1) try a non-chlorine shock, like MPS. But, my CC are so high that it would be an exceptionally high dosage of that type of shock. I don't know whether that's a great idea. I absolutely do not want to end up in a situation where I have to drain the tub again, if it can be avoided. I can't tell you how time consuming it is to dump 18oz of acid into a 190 gallon tub. It literally makes me want to cry to think about doing it a 4th time in 10 days.
The other idea is to get an aquarium UV lamp off Amazon. That wouldn't hurt anything, but I'm not sure whether it'll help. I have a whole-home UV disinfection system for my well water, which sits just past the water softener. So all the soft water entering the tub has already been UV treated... but, on the other hand, the wholke-home UV system wouldn't have had any action on potential nitrates - since they weren't bound by chlorine when they passed the UV bulb prior to entering the tub. (All of our drinking water goes through point-of-use RO filtration inside the house, so using RO water to fill the tub isn't practical.)
So.... apologies for the length of my post... but any thoughts? I am willing to try anything at this point!
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for weak bleach!