At my Wit's End... Turning Green Again

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R

rmoors510

0
Nov 8, 2013
25
Las Vegas, NV
Hi all...

So I came to this website and forum about 6 months ago due to my green pool. All my numbers were good, except my CYA was WAY high. As much as I tried to "de-green" it, bottom-line was I needed to drain it and start over. So I did that, and for the next 5 months, I've had a beautiful pool. Over the winter, I've been making sure my pH and Chlorine levels were good. Now, as it started to warm up, I've been keeping up with my testing, but the water started to get green again, including build-up on the walls and especially in the hot tub (the hot tub is attached and overflows into the pool). Since my pool is approx. 28,000 gallons (including hot tub), I have had two chlorine tablet floaters to distribute what I thought was enough chlorine throughout the pool. Since I first noticed the green in the hot tub, I transferred one of the floaters into it, while the larger one is still in the pool. Today I went out and noticed it is getting greener, with more buildup on the walls, and the hot tub looks like there is a thin coat of mud on all the horizontal surfaces. I tested the chemicals, and here's what I got:
Chlorine - 1 ppm
pH - 7.8
Hardness - 300
Alkalinity - 100
CYA - Didn't test... I can't imagine it's high... It's been 6 months since I've drained the entire pool, and I have used nothing but Chlorine tablets since the initial shock.

So I know chlorine is low, and I upped the amount I've been putting in. But could a couple weeks of low chlorine really affect the water that quickly? I decided to throw a 20,000 gal Shock packet in tonight, much to my dismay, since I really like to avoid shocking to keep CYA down. But I want to make sure the green goes away before it's time to start swimming... which in Vegas, is probably a couple weeks.

One more thing... there is always a little bit of dirt at the bottom of my hot tub, no matter what I do. There is one drain on the bottom of it, so I'm worried it may be clogged. That said, I checked it when I drained it six months ago and it was free from debris.

Any help would be appreciated. The only other thing I can think to do is clean my filters again. Aside from that, I'm out of ideas if a quick shock doesn't do the trick.

Thanks!

Bob
 
Bob here are my thoughts.
1 You have very low FC
2 You don't know your CYA level which you need to know to maintain the proper FC level to prevent algae.
3 Your using chlorine tabs which add CYA with each one
4 What was the shock you used after the refill ? More CYA.
5 What was the shock packet you just used ? More CYA.
6 You need to SLAM the pool to clear it of algae. In order to do that we need to know the CYA level to see if it's in a acceptable range.
7 What test kit do you have ?
8 You need to go back and do some reading in pool school.
 
Six months of trichlor tablets could easily raise the CYA level by 200, assuming 2 ppm of chlorine a day, getting the CYA level way too high. Even if you were using much less because it was winter, you might be alright, but still approaching max reasonable levels, then add in a little dichlor shock and your CYA could very easily by too high.

This is the fundamental problem with using tablets, they add CYA and there is no easy way to get rid of it without replacing water.
 
From what you have posted here, I'd say you didn't quite get the whole idea of a Trouble Free Pool.

6 months of tabs WILL bring your CYA up to unmanageable levels. You do need to test your CYA level, and I'd be willing to bet it will be close to if not over 100.

All solid forms of chlorine contain either CYA or calcium. Using any solid form exclusively will lead to problems in short order, as you are now finding out.

For your own info, list here the ingredients in each of the products you've been using in your pool. I'm almost sure the total list will surprise you as to how much CYA and CH you've been adding to your pool.

As Pwrstrk has mentioned is would be a very good idea for you to read through pool school again, several times if needed for things to come clear.

edit: looks like you both beat me to it........
 
rmoors510 said:
...
Any help would be appreciated. The only other thing I can think to do is clean my filters again. Aside from that, I'm out of ideas if a quick shock doesn't do the trick.

Thanks!

Bob
Click to expand...
Dirty filters don't cause algae. They should strain it out, once it's dead. Algae will cause dirty filters, but not the other way around.

There is no such thing as a quick shock. You might get a good kill on the algae with a massive dose of chlorine, but that's only one battle, not the whole war. It will be back unless you eradicate it completely. And for that, it takes high (not massively high) levels of chlorine for an extended period of time. And a lot of brushing, to break off the protective skin algae grows to protect it from chlorine. It's all covered in great detail in How to SLAM your Pool

Without knowing your CYA level, you will not know how high you need to raise the chlorine. As an aside, every puck you've fed your pool has raised the CYA 1.2 ppm. It doesn't evaporate. It just grows and grows. A 35 lb. bucket of pucks will have added 83 PPM CYA , which is too high, even for the Las Vegas sun. Two bags of dichlor will have added another 4.3 CYA to your pool while only adding 4.7 FC, which isn't even shock level for zero CYA!

With the right test kit, the directions in Pool School, and lots and lots of bleach, you can get your pool clear and keep it that way for the rest of the year. Years, actually; I haven't had to "shock" my pool for algae once in the four years I've been maintaining it.

yodapoolschool.jpg​
 
Thanks, Richard. And thanks to everyone else that posted. In the 6 months of winter out here, I'd say I've gone through maybe 20 pucks, so per your calculation, I've raised CYA 24 ppm. Plus the Dichlor tonight, so a bit more. The reason I didn't test CYA is I was out of the testing chemicals, so I'll need to get more to be sure. I did SLAM it when I first refilled it, using strictly bleach so as not to raise CYA. Before I started caring for my pool myself, I used a pool service that utilized pucks as well, but I never saw (in over a year) a change like I've seen when taking care of it myself (and he never drained it)... that's why I feel I'm missing something.

Let me ask you this. From a guy that can spend time on the weekend caring for his pool, what's the best method for chlorine? When I slammed it, I bought a ton of bleach for the 28k gallon pool. Other than clearing out the grocery store, where can I get bleach regularly to put in on the weekends? The forums here I read said daily additions to the pool if using liquid bleach. With my job, that's not an option. So Lithium Hypo?

I'll get you a CYA reading as soon as I get another kit. For PwrStrk, the test kit I'm using is the HTH 6-Way test kit. A Wal-Mart cheap-O version.
 
You can go the liquid chlorine injection route. Your still dealing with getting liquid chlorine.
I think an SWG will fit your situation better. It's not a totally set it and forget thing you still need to test once in a while, but lots of people here have them and love it for the connivence of it. Look into it.
Too SLAM your pool and for general testing the TF-100 kit with the XL option is the way to go. The SpeedStir is also handy to have.
 

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Thanks all. Thanks for the support. Isaac, when I'm here, I definitely have the time to commit. My concern is when I'm not. And the pool service guys just use Trichlor like I've been using...

I'll get my CYA level, switch to bleach, and try that. The question I had for Richard I extend to you all... Where can I get the amount of bleach I need to keep my pool at the levels it needs to be without clearing out the grocery stores? I wasn't lying when I said I cleaned out the grocery store of all their bleach. Lowes/Home Depot - same thing. Pool stores seem to only sell Trichlor/Shock. Any recommendations?

Thanks again for all the help!

Bob

- - - Updated - - -

One more thing, the pool was salt water but the previous owners converted it to fresh water claiming it was more work to upkeep a salt water pool.
 
The amount of bleach you need isn't much, after the SLAM is complete. Probably 1/2 gallon to 3/4 gallon per day of 12.5%. more if it's 10% or 8.25 Chlorox. You can find it at big box hardware stores in the pool section, but sometimes the stuff has been sitting for a season and has lost strangth. Some independent pool stores sell the high-strength stuff. I'd let my fingers do the walking. And keep your eyes peeled for pool service trucks. If you see yellow milk crates (they're bleach crates, really) in the back, ask where they buy it.
 
rmoors510 said:
All,

Here are some updated numbers for you:
FC - 4.0
pH - 7.6
Alkalinity - 120
CYA - 20
TDS - 1000
Phosphates - 400

Phosphates really high?
Click to expand...
We don't pay much attention to TDS or Phosphates around here. Those are pool store results, correct? You'll have to get one of the recommended test kits if you want to be in control of your pool. Without one, you may never get that algae completely eradicated.
 
SLAMing it now. Yeah, I read that phosphates don't matter. But that leaves me wondering what is causing the issue. It's obviously not the high CYA everyone was mentioning (surprising to me too after doing the math). So, just low chlorine level for too long? The only other thing I can think is when I drained it, I may have left the water in the solar panels, and just reintroduced that water in the last few weeks when I turned them on. Also, do I need to bring UP my CYA to 30-50, or just leave it at 20 and let it raise slowly on its own?
 

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