Help with Green Tint

[ETXdbw]

This is my first post so be gentle.

I included some test results and photos below but first the background story on how I got here.

We had this same green tint for about 24 hours when I initially filled the pool in May. It went away within 24 hours after only adding half a shock bag and half a gallon of muriatic acid from the pool store. I added a bag of shock once since then but otherwise maintained the pool with chlorine tabs. We had significant rainfall during June and early July which washed out an area near one of the support legs and caused it to dip. So earlier this past week we drained the pool to repair the ground around the leg then refilled the pool. Since refilling the pool, this green tint has slowly improved but it has not gone away.

Last Sunday PM - Monday PM I drained the pool. The pool sat with small puddles at the bottom overnight Monday PM to Tuesday AM. Tuesday AM the repairs were completed and the refill process began. The pool was full by Tuesday PM at which time I added a half bag of shock and a gallon of muriatic acid (our local water source is known for its high pH). I also added .25lb of stabilizer from the pool store. The sand filter ran continuously from Tuesday PM to Thursday PM. The water was noticeably cloudy with a green tint after refilling the pool. I could see the squares at the bottom but the pool was not clear. The pool store chemicals were all Bioguard products.

Our water is city provided but we live in the country so the city water supply comes from a serious of wells.

When the water failed to clear by Wednesday PM (though it did improve) I found this website and ordered a TF100 which arrived late Friday. I also added the other half bag of shock to the pool Wednesday night. The test results below are all from the TF100.

Saturday AM Test results:
FC 10.5
CC <.5ppm
pH 7.0
TA 310
CYA 60
CH 25

- I backwashed the filter then added Borax as recommend on the pool calculator to raise the pH (at 12pm)

Saturday 9PM test results (after sundown):
FC 7.5 ppm
CC <.5ppm
pH 7.8

Sunday 7:30AM test results:
FC 7.0 ppm
CC <.5ppm
pH 7.8
TA 320
CYA 60
CH 25

Here are two photos - the blue water was taken last Sunday prior to draining the pool. I had regular pool store testing (bi-weekly) that never showed any issues other than needing to add a couple of pints of muriatic acid and stabilizer.


The green water photo was taken this morning (Sunday AM) after testing the pool.



So- I would appreciate any ideas or suggestions on what this could be and how to fix it. Or do I just have to go SLAM it?

Thank you in advance for your help.

 

[mknauss]

Welcome to the forum!

Good job on getting a great test kit. Now, it appears the water is really clear. So, the green is most likely iron? If so, it is at a stage that it should be able to be filtered out. There are methods detailed in threads in this forum using polyfill or other filtering mechanisms. Do a search - upper right of page is a search box.

Wish you had not added the borax - your pH will rise quickly with your TA and aeration. The borax raised both the pH and TA.

Your CYA is as high as you want it, so do not use any more solid chlorine products. Chlorinate with liquid chlorine/bleach from now on. Follow the chlorine/CYA chart for FC to have based your CYA. Use PoolMath to calculate amounts.

Take care.