Chemistry Issue On New Fill w/Well Water


New member
May 3, 2008
Southern New Jersey
Hoping someone can shed some light on this issue. I have an IG Fiberglass 16K that is 14 Yrs old. It had an Algae issue at the end of last season and in the spring I decided to Drain it and clean the chalky fiberglass with Muratic Acid. I also did a few fiberglass repairs on a couple of cracks. I have filled the pool with about 14-15K of Well Water and insured I had back-washed the night before. (In hindsight I probably should have back-washed twice.) Pool was perfectly blue and testing showed no chlorine and my Taylor pH indicated adding 8+ Lbs. of Soda Ash to get close to 7.0

Once I added the Ash the water turned from an awesome blue to a brownish green. I have had this happen in another small pool 15 years ago upon shocking only to learn it was iron in the water reacting to the chlorine. Can anyone tell me if this is also the same issue? 15 Years ago I used a hose off my sprinkler that did not pass through my softener. I made sure to not do that this time. I did no other tests at this point and assume everything else is zero. If more info is needed pleaase let me know and I will be happy to add.

Thanks in advance for any guidance you can provide and have a safe and healthy summer!
It's pool time in the North-East (Well Almost)


TFP Expert
LifeTime Supporter
Jan 6, 2010
San Dimas, CA (LA County)
A pale sickly green is most likely Iron. Raising pH will drive it out of suspension,. so will bleach.

I just answered a similar thread a few days go.
Look at the pictures.
There's this: If you’ve got iron in your fill water, use Polyfill to remove it
And this: A Tale of Two Filters... and Ugly, Rusty Water.
And lastly: Well this is crazy, pool green in 1 hr...copper I assume - party tonight. :(

If your wife crafts, you likely have polyfill already. Pack some on the skimmer. Or just layer half a dozen paper towels in the skimmer and see if they turn orange in a few hours. Then it's your call if you want to try filtering it out first or skip straight to a sequestrant.
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