Long story - 23K gallon concrete pool. DE. Nature2.
We had this new pool built 6 years. For some personal reasons, I couldn’t get around to get serious about the maintenance. So, I would add 2lb bag of chlorine every other week, kept a few tablet packs in a floater, and was running Nature 2 mineral sanitizer.
The pool is at the lower end of the development so there was a significant water runoff in the 1st year. Also, in a 2nd year. After that we improved the water drainage and not much is getting into the pool from the lawn.
I am afraid that during the first two years I might have gotten a lot of organic junk into my pool.
Last year, I finally started to see some algae. Easily brushed off. Hit it with 2 bags of Aqua Chem SuperBlue – all gone. I started getting worried when my in-law told me that after he shocks the pool, he can’t swim, and I told him that I don’t have this problem. Even after adding 2 lb of chlorine bag, I get not much Chlorine reading.
Finally, this year, I decided to get serious and started with testing on my own (TFT-100) and then taking to pool store. The results were very close. I will show range of two numbers as I am always a bit off.
Monday – 3rd day after pool was open.
In the morning – I took the water to store.
FAC - 0 - 0.5 (likely 0)
TC - 0 - 0.5 (likely 0)
CH – 200
CYA - 0 (yes 0)
TA – 80 - 100
PH – 7.6 – 7.8
TDS = 600 (ok)
Pho – 0
When I explained that I had no chlorine reading last year – they checked for Nitrates (with a strip) and told me – they are off the charts – 150? Told me to drain water and not waste money on balancing.
Monday night -
I added 4 lbs of Stabilizer to the skimmer (removed the plastic baskets).
poured 3 x 121 OZ 8.3% Bleach.
In the morning – got no reading of Chlorine.
Nitrates Strips arrived. They have 50 max. So, I used ¼ pool ¾ tap water, got reading of 10, so x4 = 40. Still very high.
CYA I had measured at 20-25.
In the evening – Put 2 bags of Sodium Dichloro-s-triazinetrione 63.05% (Chlorine 39%). 30 minutes - No change in Chlorine. Added another 3 bags so now it was 5 lbs total.
In the morning – still practically no chlorine. Not even Total Chlorine. I got maybe 1. Took to pool store
Here are the latest readings:
FAC - 0 - 0.5
TC - 1.5 – 2
CH – 200 – 300
CYA - 40-45
TA – 100 – 110
PH – 7.4 – 7.6
TDS = 1000 (ok)
Pho – 0
The guy at Leslies encouraged me to replace at least ½ of the water. I said, I wanted to continue with chlorinating. He suggested to drop two bags of Oxidizer (potassioum perox….) 4% oxygen to release free chlorine. I did this Wed night.
I also bought 8 gallons of liquid chlorine. I also have about 6 jugs of 8.25% Clorox (about 5.7 gal). I haven’t started putting it in.
I didn’t put new Nature 2 cartridge yet.
It is getting very nice and water now is around 77. The pool has a good, but not extreme, sun exposure during the day. The water looks very clear. I don’t see any algae.
I have read that absence of CYA at the opening of the pool may suggest Ammonia. Also, nearly 0 TC / FC in the morning after suggests something consuming it at night – 2.8 gal of 8.25% bleach on Monday and 5lbs of chlorine on Tue and nothing to show for it.
Can I start using pool? After all, we managed the whole last season without chlorine. Is it not safe? Should I replace ½ of the water to try to lower nitrates?
Do I need to continue chlorinating until I get the FC to stay?
I have read a few threads in the forum, and it seems like my case is not unique. I also noticed that with the help from the forum members people had solved their problems. As I am struggling though and really hoping to get some specific guidance here.
Kids want to get into the water. Please help!