Just fired pool company now I'm trying to fix several problems.

[DD-TNT]

Good morning all,

First time posting after reading a lot of good information.

Last week we fired our pool company after testing the water and finding every parameter out of range and having black algae around the bottom perimeter and sporadically over the bottom.
CYA ~200, FC 2.5, CC 0, TA 150, CH 525, TDS 700, PH 8

Since then I have shocked the pool with 18 lbs cal hypo 68% broadcast over the bottom, added 2.5 gal of muriatic acid (over three doses) and changed 8% of the water. My new readings are.
CYA~165, FC 15, CC0, TA 120, CH 475, PH 7.6.

The addition of the new pipe water 5 days ago turned the water green and it has been slowly getting lighter. The remnants of the cal-hypo also have the pool cloudy as the vac did not get all of the residue.

I know I need to change more water to get the CYA down but this is a neighbourhood pool and I dont want to close it for the three or four days that it will take to refill. I have the ability to add softened water slowly (from a residential water softener) and would prefer to make piecemeal water changes.

My question is three fold
1) What should be my priority for treating?
2) Do I need to do anything about the green? (sequester perhaps)
3) Should I attack the black algae now or wait till the CYA comes down?
Thanks

 

[Texas Splash]

Hello and welcome to TFP! Your biggest challenge at the moment is definitely the high CYA. Assuming it's at/about 150-200, that makes FC (chlorine) management very difficult. I understand you prefer not to do a partial drain, but that would be ideal. Before going that far though, can you confirm what test kit is being used to test the water? DO you have a TF-100 or Taylor K-2006 test kit?
About your questions:
1 - Lower CYA
2 - You need to SLAM via Pool School - SLAM - Shock Level And Maintain
3 - Managed by question #2; correct chlorine (FC) and CYA levels will treat algae.

Last question - do you know if you have metals in the water? Is your water from a well that may have iron or copper in it?

 

[DD-TNT]

Thanks for the info, I am using a Taylor k2600 test kit. My water comes from the city supply but it is possible that they source from local wells as this is common in the area.

 

[Texas Splash]

The K-2006 is a good test kit. TFP encourages the use of regular liquid bleach as our primary sanitizer for non salt water generated pools. If you have a source there locally where you can get regular liquid bleach, that would be ideal because it won't increase the CYA any further while you sanitize the water and decide what you are going to do about the CYA (drain or not). If the new pipe/water source is brining water with metals to your pool, then that is a significant challenge as iron/copper tend to react to the chlorine. If you do discover that you have metals in the water source, let us know and we'll try to give you some good ways to manage it. When deciding about the CYA, please look at the link below in my signature for the Chlorine/CYA Chart. There you will see the relationship between FC and CYA, and how high your FC needs to be if your CYA is also high.

 

[Agent99]

Have your fill water checked for metals by your pool store. This is the one time where I would kind sorta trust them as most folks don't regularly need to check for metals. Well water has a higher probability of having metals versus city water.

 

[DD-TNT]

Thanks for the suggestions, I decided to tell everyone the pool is closed for the rest of the week and I am presently dumping 60% of the water to take the CYA down to approx 60. I will see if the pool store does testing but I doubt it. I'm not in the US and have not seen metal test for sale anywhere. Ironically I can buy metal sequestering chemicals.
I think I read (on this forum somewhere) that the water will not turn green until I add the chlorine so I guess I can use that as a check for metal??? If it does turn green at that point I will add the sequestering agent.
Rgds,
Darren

 

[Texas Splash]

Yes Darren, that actually would be a good thing to try. Test some fill water separately with a little bleach/chlorine. If it does change, well, sequestrant is the primary method of long-term management, with a few other small tricks we know about. Good choice to lower that CYA! Hope everything works out soon for you.