It's a long story.
I've had three issue for going on two seasons. I have a 14,000 gallon fiberglass pool. I've had the pool for 5 years an the only problem I had was iron stains when I opened the pool in the spring. I'd add a product called stain out, then metal out 24 hours later and the problem was gone for the rest of the year.
Last year I added a salt water chlorinator. All last season I couldn't keep my chlorine levels up. The only way to keep them up was to run the chlorinator at 100% 24 hours a day. I'd then get iron stains starting at my jets, then eventual covering the entire pool. The old stain remover I used was no longer available so I've tried others. Then all work, the stain would be in gone in a day. I then add a sequestering agent, wait a day, vacuum the pool and clean or even replace the filter. I then try to get my chlorine levels up, running the chlorinator at 100% for day. After about a week the stains come back.
This went on all last year and cost me lots of money in chemicals. This year when I opened the pool it was a swamp, green and stinky. I'm assuming because I can't keep chlorine in the pool there was nothing to prevent this from happening. I drained the pool down half way, refilled it using a special metal filter, added 5 gallons of liquid chlorine and ran the pump for a couple of days. The pool cleared up nicely, allowing me to see the dark iron stains. I balanced the pool, turned off the salt water chlorinator and went back to my old chlorine tablet chlorinator.
I ran it for a couple of weeks this way with the stains, but couldn't keep my chlorine and PH levels up. I added the stain remover. The stains went away, I then added a sequestering agent, vacuumed the pool, and changed the filter. With the stains gone I keep added the required dosage of PH plus, and keep my chlorinator cranked up. The PH stays down and the chlorine level only raise if I run the pool 24 7 with the chlorinator at a 4-5 out of 10. I only used a setting of 1-1.5 in the past. I'm using tons of PH plus and buckets of chlorine tabs. My local pool store recommended I shock it every day until I can maintain chlorine levels. I did this for two days, and my iron stains came back.
As well the water burns your eyes. I'm assuming do to the low ph.
All my levels are perfect except my PH and chlorine levels. I tested as well as my local pool store.
I'm assuming something is eating my chlorine. With the saltwater, or tab chlorinator cranked up, that high chlorine level water coming out of the jets is causing the iron to release from the water. That's why I see it first at the jets. Once the chlorine gets into the pool it is eaten up. Where is my chlorine going, and why wont the PH stay up? I think if I get these items corrected I can get rid of the stains by using ascorbic acid and Jacks Magic Pink stuff.