Crystal clear to green overnight

May 4, 2015
31
Knoxville TN
Pool Size
35000
Surface
Plaster
SWG Type
CircuPool SJ-40
35,000 gunite pool. Sand filter.
A week ago, the water was crystal clear and all chemistry was good except Ph and TA were way high and off the scale. I went to the TFP calculator and entered the info. The calculator instructed adding 64 GALLONS of Muriatic Acid. Fortunately, Home Depot only had 34 gallons and that's what I added. Stupid, I know. So I went from WAY high to WAY low. I have been adjusting ever since and I would now estimate the Ph is a little over 8.2 and TA is now at 180. BUT, in the interim, the pool turned green over night Tuesday of last week. I added 18 gallons of 8.2% bleach, but that did not help. So I added a gallon of Sam's Club Member's Mark Algaecide 40. No help. And I have brushed and vacuumed numerous times.
In frustration, I took a sample to a pool supply place. They sold me 4 small packets of Poolife Mustard Algae treatment along with ph adjusters. Still green. Back to pool place and they send me home with 1 1/2 quarts of Algaekill II and tell me the sand filter could be an issue. Algaekill II was no help so I add ANOTHER gallon of Sam's stuff. Still green.
I have shut off the pump and more dead algae is on the bottom of the pool. Will vacuum and brush again, but at this point, it's safe to say the water will still be green.
Current readings: Ph >8.2. FC: 7. CC: 6. TA: 180. CH: 225. CYA: 45.
Any suggestions?
 
Welcome to TFP!

The first step is to get the PH right, and to moderate your PH additions so you stop overshooting on PH changes. I suspect you are using PoolMath incorrectly somehow. Remember that you need to enter your TA and borate levels for the PH calculation to be correct. If you don't know your borate level, assume it is zero. If you continue to get numbers like 64 gallons of muriatic acid, you are doing something wrong with PoolMath and need to pause and figure out what that might be.

Once you have the PH around 7.4, it is time to SLAM the pool, as described in Pool School.
 
Is it Emerald Green or murky green? And do you have a heater? As acidic as things got, you might have etched the innards of the heat exchanger and that green is copper. That algaekill II is also copper-based.

I'd consider a drain and refill at this point. It might be cheaper than all the bleach and all the metal sequestrants you'll be buying. You'll still need a proper test kit to get the new water balanced and keep you out of the pool stores.
 
Thanks, Richard. It's emerald green. I disconnected the heater 9 years ago when we got our first gas bill before we had even moved into the house. It was $984 and I think I was in the pool 4 times and my wife twice.
I hate to think about having to drain the pool to straighten this out, but if that's the only way...
Should I try slamming first?
Thanks again for your input
 
Also, I have the TF 100 test kit and have been using it for probably 3 years. I am not aware of a borate test that can be run with it. One of the biggest problems I have is comparing the colors for chlorine and Ph. When the red on the Ph is redder than the highest reading, do you just have to guestimating how alkali the reading is?
 
Also, I have the TF 100 test kit and have been using it for probably 3 years. I am not aware of a borate test that can be run with it. One of the biggest problems I have is comparing the colors for chlorine and Ph. When the red on the Ph is redder than the highest reading, do you just have to guestimating how alkali the reading is?
When it's off the scale, there's no real way of knowing just how high it is.

The green might be from the copper algaecide. Check these two threads and compare the colors in the pictures.
http://www.troublefreepool.com/threads/75264-Crystal-clear-green-water
http://www.troublefreepool.com/threads/45401-Clear-Emerald-Green-H2O

If you think the green might be from copper.... as messed up as your chemistry is already, I'd drain it and start fresh. Water is not that expensive, but if it is copper, you'll be buying sequestrants forever.
 
From what I read on those links, I have no doubt the problem is copper and probably other metals as well. And still, maybe some algae.
There are algae (I think) stains all over the pool that are coming off when I scrub like crazy with a steel brush. I had been using a nylon/plastic type brush previously which removed zero staining. But scrub-brushing the pool will probably take a full day...or more, and is probably not really possible with the pool full.
Much as I hate draining it (I pretty sure my water bill was >$600 last time I did), if I did, could I pressure wash the stains, or would that damage the gunite? And would pressure washing remove the metal stains as well as the algae stains?
 
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