Green Mystery

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R

rpete

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Jun 25, 2016
6
Morgan, Utah
We've had an Intex pool for about 5 years. Normally when it turns green, we try to clean it up, but end up just draining it and starting over.

This year when it finally turned green, here is what happened. I dumped probably a cup worth of algaecide (the rest of my gallon jug) and about a cup of muriatic acid. I also shocked it with dichlor crystals. Surprising to me, it turned a milky blue, which is progress compared to other years. Then I tested it for chlorine and it read zero even though I have two 3-inch trichlor tablets floating around all the time. This year we inherited a free test kit that included alkalinity, so I tested it for alkalinity and it was 210 ppm. I shocked it again, but the alkalinity is still high, 220 ppm and chlorine is still zero. Water is still a cloudy blue. I'm about to drain it and start over, but was wondering if there is a solution. At least a learning experience I can gain.

My test kit does not include CYA
 
Pool School. ABC'S of Pool Water Chemistry. You can start there.
 
I've gone through the ABC's. Here are my results:
FC - zero
CC - zero
PH - 7.5
TA - 220 ppm
CH - my test kit doesn't test for this
CYA - my test kit doesn't test for this

I've managed to go from green to blue. now how to go from blue to clear? As I understand, it's easier to keep it clear than to clear it up. So draining and starting over is probably what I'm going to do.
 
I wouldn't say that. I don't have my test kit yet (should be delivered this week) so haven't done it the right way, but I went from pea soup to clear with just liquid bleach. A lot of filtering and brushing and vacuuming too, but still easier than draining, cleaning and refilling.
 
I have found that if you don't know what your CYA level is, you will never keep the water clear, at least here in Texas. My bet is your CYA is near 0 and this will allow your free chlorine to be eaten up by the sun, in turn giving you a green pool. Get the TFP recommended test kit and follow pool school here and 95% of your woes will be gone.
 
You need a proper test kit as mentioned above. You cannot wing it with your water. I used to do the same thing and let me tell you, this is so much easier once you start testing properly. And stop dumping random chemicals until you have a full set of test results. Keep the chlorine high and keep brushing until you get your test kit, stop everything else. When you get your kit, run all the tests and post up the results.
 
The green is no mystery. Without free chlorine in your pool, all the filtering in the world isn't going to keep it from going green.



You need chlorine and CYA (aka stabilizer) in that pool PRONTO! Then you can worry about clearing up the cloudiness. Otherwise you're fighting a losing battle.

Plain old bleach is what you need. No fancy pool store potions and no more algaecide.
 

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You need a DIY test kit that includes a CYA test. Before you do anything, order a TF-100 (there is a link in my signature). It should take under a week for delivery. Each evening, after the sun goes down I'd add 1/2 jug of regular unscented concentrated bleach (8.25% NaClO concentration) until your kit arrives. You've added trichlor, but the amount is quite ambiguous, so thee there is no telling how much stabilizer is in your pool (please don't waste your time going to a pool store. Results are unreliable at best and used by the clerks as a catalyst to sell you something you really don't need). If the water is green and/or cloudy, it is not advisable for you to swim anyway so the un-stabilized chlorine won't be harmful, and it won't be consumed by the sunlight.

Once you receive your test kit, run a full panel of tests, FC, CC, CYA, pH, TA, and (least importantly for a vinyl pool, but good to know for certain accessories.) CH. Using Pool Math, adjust your pH to 7.2, add enough CYA to a tube sock to get it to 30ppm. Tie it off and putting it into the skimmer, giving the sock a squeeze every so often. You don't have to test CYA for about a week after you add it. It takes some time for the granules to dissolve and for the water to show a reading.

Finally, add enough bleach as indicated by the CYA - Chlorine chart to SLAM the pool (how-to in my signature). The more diligent you are in testing and dosing the water, the quicker your SLAM will take. Vacuum and brush throughout the process as well.
 
Thanks for all your responses. I've learned much already. Next question, I'm on a pretty tight budget. Even the TF-50 option is alot for me. I already have a Taylor K-1003. What if I purchased the R-0013 CYA refill for $8. Would that work for me?
 
It looks like the refill is just the reagent. You also need the beaker and mixing bottle.

I realize you are on a tight budget, but if you can find the funds, the full test kit will save you a virtual small fortune in the long run. Literally $100's each season in unpurchased unnecessary chemicals at the pool store.
 
Husky25 said:
It looks like the refill is just the reagent. You also need the beaker and mixing bottle.

I realize you are on a tight budget, but if you can find the funds, the full test kit will save you a virtual small fortune in the long run. Literally $100's each season in unpurchased unnecessary chemicals at the pool store.
Click to expand...

AMEN to that!
 
FC is set based on CYA and the [FC/CYA][/FC/CYA]. Chlorine must be maintained above minimum at all times for the pool to be safe, sanitary and algae free.
 
First of all, add enough muriatic acid to bring your pH down to 7.2 Then no more tablets, no pucks, no shock, just bleach. Add enough to bring your FC to 16 and keep it there until the water is clear and your FC drops no more than 1 overnight (what we call an overnight chlorine loss test, or OCLT). Then let your FC drop to 3-5, no lower than 3, and keep it there by adding bleach daily.







Go to the PoolMath link at the top of the page to see how much bleach to add.
 

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