The green algae tint that will not go away

[Orion]

In 17 years of opening this 20x40 vinyl pool (guessing around 30k gallons), I've never had as stubborn a problem with clearing the water as this year.
Nothing unusual about the condition of the water when the mesh cover was taken off. Same lake-water brown as always. This time, the water is finally clearer after 2 weeks of running the filter and almost daily liquid chlorine loads. I can see the deep bottom through the murk.

I lost my old "Ben" test kit (don't ask) so using the simple red/yellow walmart special. The PH is mid 7's.

I use 5 gallon jugs of (allegedly) 12.5% liquid chlor, directly in the skimmer. I also use 4 or 5 of the 1-lb granular shocks from whatever store has the best active ratio (53% is the best I have found). I've never used nearly so many gallons of liquid before, but the green tint will not abate. It looks clean in terms of no milkiness.

The bottom is spotless from vacuuming. The only new variables are a new liner last season (new water), and replacement of an old DE filter with a new sand filter. I understand the sand is not the filter medium that DE is, but it seems to do almost nothing while running 24x7. As to the water, since it is fresh, I am trying to add some stabilizer via some pucks I have around, but without the Taylor kit, no way to measure where that is.

As an aside, I wonder if the liquid is being diluted by the pool store and is no longer actually 12.5%. There is no indication other than what the clerk states.

[CarlD]

Have you tested for metals in your water? Sounds like you may be trying to get rid of copper or iron with chlorine--which won't work.

The Taylor K-2006 is pretty much the same as the old PS kits. They run $50-$70. Sounds like you need it.

You can test the concentration of the LC, but only if you have the FAS-DPD test for chlorine. You simply add .5cc of LC to 5 liters of tap water (test the tap water first for its FC level), and test it for FC. You're mimicking the concentration of adding 1 gallon of LC to 10,000 gallons of water. The FC level that results (minus the FC level of the tap water) is the approximate concentration of the LC.

[FormerBromineUser]

Nothing unusual about the condition of the water when the mesh cover was taken off. Same lake-water brown as always.

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Carl's got you. You are in great hands!!!

Just an aside and my apologies for side-tracking your current issue...

Next year, try opening earlier before your water temp gets above 60 degrees or so. I have watched my neighbor with a mesh cover open early: sparkling. Late: brown. No guarantees or expertise here, just an observation. And a thought.

[Orion]

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Carl's got you. You are in great hands!!!

Just an aside and my apologies for side-tracking your current issue...

Next year, try opening earlier before your water temp gets above 60 degrees or so. I have watched my neighbor with a mesh cover open early: sparkling. Late: brown. No guarantees or expertise here, just an observation. And a thought.

My pool closing guy also suggested switching to a solid cover. Just waiting for the time when the mesh is dead before spending the money.

[swimdaddy]

I have also had trouble this year with clearing up the pool, but all my numbers are good and water is clean, just not clear and a tinge of green. Figured out my wife was vacuuming the pool and was not vacuuming to waste, and the sand filter was literally pulvarizing the dirt, pollen and dead algae into a greenish solution. After I figured it out, we kept the kids out for a couple of days and let everything settle to the bottom, then vacuumed to waste and the water has been clear ever since. I also tried using a little DE in the filter as Carl suggests and that has been helping. But I have learned, vacuum to waste when using a sand filter!

[JimK]

.
Carl's got you. You are in great hands!!!

Just an aside and my apologies for side-tracking your current issue...

Next year, try opening earlier before your water temp gets above 60 degrees or so. I have watched my neighbor with a mesh cover open early: sparkling. Late: brown. No guarantees or expertise here, just an observation. And a thought.

My pool closing guy also suggested switching to a solid cover. Just waiting for the time when the mesh is dead before spending the money.

Our pool came with a mesh safety cover. In order to avoid opening to a green pool I had to wait until late Nov to close, and had to open by beginning of March. What a pain.

After a few seasons of that, I decided to "convert" to a solid cover. Since the mesh cover was still in great shape and a new solid safety cover would be expensive, I just bought an inexpensive tarp style cover and placed that over the mesh cover. Since doing this (I think adding borates helped too), I can now close in early Oct and open in early May with no green pool. One season I couldn't open until June 8th and the pool was still clear!

Definitely get a proper test kit (the Taylor K2006 is the one recommended here) and perform a proper shock; keep FC at or a bit above shock level, appropriate for your CYA level according to the Best Guess Chart, until these three condition are met;

1. Pool is clear
2. CC is .5 or less
3. Overnight FC loss is 1ppm or less

[Orion]

I'm now at a loss. I had the water tested to find all was in order (some low ALK), but 0.4 ppm iron (no copper). They gave me a bottle of Metal Away, or whatever it is called (yes, yes, I know...) and it did nothing I can see. They also threw in a couple of the sock bags and said to run it for a couple of days, backwash, repeat.

Although the backwash did show a healthy amount of brown, the water remains green-tinted and hazy in the deep end (clear but tinted in shallow).

All I have left to try is to add some DE to the sand filter, and also hunt for a proper chelation agent.

Any other thoughts?

[Lawrosa]

You need to post full test results.



If you have iron from what I know you cant really get rid of it.

You probably need to shock the pool and keep it there for a while. If iron stains are an issue then use the pink stuff here but follow the instructions..

http://www.jacksmagic.com/products/JMPINK032.html

[Lawrosa]

Plus what are you adding to the pool?

Common source of copper is copper-based algaecides. The cheaper ones often supply copper ions rather than complexes and, if too much is used, will result in green pool water.

If the water changes color after chlorine (or any other oxidizer) is added, the swimming pool water probably contains a metal.


Shock the pool to oxidize the metal, which then settles out of solution and looks like rust. The rust can easily be vacuumed out of the pool.

Add a sequestering or chelating agent, which forms complexes with the metal and prevents it from being oxidized by the chlorine.

If the source of the copper or iron cannot be established or if it cannot be avoided, regular addition of a chelating agent or sequestering agent (metal out products) will ensure that any new metal arriving in the pool water will be held in an inactive complex.

[Orion]

The previous sample tested at 16.5 ppm free chlor. I raised the ALK. Ph was 7.2

I never use anything except borax (ph was quite low when opened) and the 5-gallon liquid chlor. Aside from that, some granular shock from Walmart or Home Depot.

The water was brown/green lake water when opened, and I shock/add liquid chlor right away. So there is no way to tell if this added to the metals problem. Same routine I follow every year except that about half of the water was trucked in last season (the rest from the muni - garden hose).

The pool has been doused with chlorine for weeks.

I can't tell if the color is due to staining, as the first few inches of the liner are normal (no water level changes over the winter). Although I can easily see my aquabot in the deep end, it is a bit murky.

I'll take another test tonight and post. The pool store has a fancy new test rig, so I mainly ignore the suggestions to add $50 of "ph up" and whatnot, except for the Metal Away bottle which is Latin for "twenty bucks away".