Chemistry Looks Right But Pool Still Cloudy/Green

May 11, 2014
12
Dallas, Georgia
We've had a pretty terrible start to pool season, starting with taking off the safety cover to find Surprise! no water in the pool whatsoever, save for maybe 3 inches at the bottom of the deep end. Took several days but we identified two separate holes in the liner which we patched and luckily the liner was still viable.

Then we tackled the next task, which is filling our pool from our very muddy lake because we are on a well which can not possibly fill the pool. This is a ~16,000 gallon vinyl in-ground chlorine pool with a 5yo Hayward Pro Series sand filter, so, it adds a lot of mud and our filter is not really the best for filtering out fine dirt. We have learned from past pool seasons that the easiest way to clean this water is to kill the algae and then add one round of flocculant. In all other seasons, this has been a 3 day process leading to swimmable water almost immediately, but we have always been starting from at least a half-full pool, never the entire pool full of muddy lake water.

Here is what I've done so far this year -

1. SLAMed to FC of 30 using regular 8% bleach until FC stopped dropping overnight.
2. Adjusted PH to 7.8 with additional of Arm & Hammer baking soda (~5 lbs).
3. Added one bottle of flocculant (on recirculate of course), waited 48 hours.

At this point, the pool is usually totally clear just waiting for the sediment to be vacuumed out, but instead the pool was still very cloudy and a blue-green color (started brown and cloudy). It was more clear and we could see a lot of sediment on the stairs so the floc does appear to have done something but not everything. We decided at this point to go ahead and vacuum to waste so we could get the filter back running in case this was additional algae bloom. I was pleased to find the FC level had only dropped to 23 from 30 after sitting for two days; our pool loses 2-4 FC per day just sitting in the sun so it seemed like the algae was likely dead at least.

4. Filtered and continued the SLAM for three more days, backwashing multiple times per day and maintaining an FC level of 30. Also began running the Nautilus robot to try to help the filter, put him in twice during this time.

The water was improving slowly and dirt was definitely being backwashed. The FC level was really not dropping at all, and all the Nautilus was catching was dirt, so we decided to give one more flocculant treatment thinking maybe this was just more dirt than one bottle could handle.

5. Added second bottle of flocculant. Nearly instant, miraculous results. Dirt all settles, we can see the bottom, the pool looks great, except...

It's still green, and slightly cloudy. Like a teal green, not a murky swamp green but the kind of green that is almost appealing except our water is never this color. And it's cloudy enough that I can just barely see the bottom of the deep-end but clear enough that I can see the bottom of the shallow end clearly. The chemistry all looks spot on and I am at a loss for where to go from here.

Current test results:
FC: 26
CC: <.5
CYA: 50
TA: 70
PH: 7.4

Anyone have experience with anything like this or ideas on what to do? Really hoping to be able to swim in this thing before it's time to close it!
 
those numbers look great, could there be some iron in there or some kind of metal? take your water to a pool store and ask them to test for metals, that should tell you what is going on, ask them to test everything for a good laugh if you want :)

most everyone that explains that color water has had iron
 
Just returned from pool store and they agreed that all of my chemistry looks good and they didn't find any copper, iron, or nitrates so this remains a bit of a mystery.

They suggested my chlorine could be high enough to be reacting with something in the water that is turning it colors, which, I don't know if that's a thing but certainly my chlorine is high. (Laughably they said my chlorine was "probably 10" when it is, in fact, 23.5 right now, 8 hours of sunlight after my earlier sample of 26.) I'm considering letting it go down to the 12-15 range where we normally shock it just to see what happens, since my FC and CC numbers seem stable enough to suggest no active algae situation.
 
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