Pool is green/yellow and silty but chemistry is great, time for new sand?

Apr 30, 2015
7
New Braunfels
I am new to posting but have been using TFP pool school since I moved into a house with a pool last summer. After we got the pool all balanced and happy when we moved in last summer it was easy to manage, and then for the winter we put a cover on it (it doesn't freeze here) and left it alone.

This summer we opened it and the water was great. I put a solar cover on it to get it warmer faster so we could start using it sooner. The solar cover catches most leaves and stuff but rain water can still run into the pool and carry pollen/dirt/etc.

We have a TON of live oak trees around our pool which put insane amounts of organic junk into it. We generally have to vacuum at twice a week.

My current problem - with the cover on, I've been bad about vacuuming it, so a lot of **** collected on the bottom, primarily pollen. But the water itself was crystal clear and values were good (pH, TA, FC/TC). I vacuumed it on Monday and stirred up so much stuff I couldn't see into it anymore by the end of vacuuming. I left the cover off and have been backwashing my filter daily, making sure my bleach is good, and the water is not clearing up at all. It is still green/yellow and cloudy, and I could just see the bottom well enough to see a lot of the brown grit accumulated in the cracks and dips, but not much leaves or anything. I vacuumed again today (Thursday) to scrub up that "silt", of course stirring up a ton of it in the process.

I don't think the problem is algae because the pool is holding bleach fine overnight (I use liquid bleach, about a gallon every few days, keep the level around 1-1.5, I keep my CYA at 0 because it saves me hassle and the solar cover traps the bleach well enough). And it only got cloudy when I stirred up the stuff on the bottom on day one, and its just been cloudy every since.

Is it possible I need to change the sand in my filter? That's all I can think of at this point. I don't know when it was last changed, but it was installed like 10 yrs ago and I'm inclined to think its probably never been changed. I know some people never change their sand, but with SOOO much debris getting into my pool daily I'm wondering if that is my issue? I'm running the filter 24/7 right now (last summer I always ran it 24/7, if I turned it off it got dirty quickly).

Also I know some people add some DE to their sand, should I do that too?

Thanks for any help!
 
:wave: Welcome to TFP!!!

I agree. With 0 CYA and even with a solar cover I would expect you to lose all the FC every day.

Can you explain how CYA is a hassle?
Seems to me doing what you are doing would be more of a "hassle" just to the harshness of the chlorine on your hair, skin, and bathing suits.
 
I kept my CYA at 0 all last year too and didn't have any issues with it, it still holds chlorine fine, especially with a physical solar cover on it because it can't physically escape. My understanding is CYA is to trap your chlorine, which a physical cover does as well. Even without the cover last it would hold chlorine decently well (its pretty shady around my pool).

If my chlorine is at 1 to 1.5 (which I've tested with a brand new kit as well as strips so I feel it is accurate) - my understanding is that is a good level not bad? How could that hurt bathing suits, skin, etc at that level? Isn't anything over 3 considered high? We usually swim in it when its around 1 and have never noticed negative side effects.

The reason CYA is a hassle is it is expensive, the powder version I can never get to dissolve even doing the different methods on here (putting it in a sock tied to the ladder, putting it in a bucket and letting it sit for literally weeks, etc). The liquid kind is even more expensive, like $30 at my pool store, and of course if you accidentally do too much you have to drain water to get rid of it (not fun in drought-y TX). I find its just easier to skip dealing with CYA and dump more bleach in when its needed. Seemed to work fine all last year.

How can the green water be caused by no CYA so long as my FC and TC are high enough? I'm not understanding that?

Thanks for the help!
 
I will add that your problem isn't the sand, and yes adding DE can be a great thing to assist your filtering. However, your issue isn't the filtering, but your water balance regarding FC. Running that level is bound to keep you in trouble. If you would run up to 40-50 Cya and keep Chlorine (FC) at 4-6 all the time you will never have Algae issues. Staying that low, you'll never be able to avoid them, because it won't be possible to maintain that residual with no Cya. Not consistently.

edit:
I was replying while you posted. Your cover will not keep chlorine in by trapping it. It may shade it some, and prevent a little loss by shading, but that's all. The reason you'll go green, is that you will dip too low on FC. CYA will not dissolve in a bucket like that, and given time, it will dissolve in the pool. It's good to have not only because it protects FC com sunlight, but it buffers the harshness of it as well. It stabilizes, hence the other name for it. Minding what you do, there is no threat of putting in too much.
 
What we teach here on the forum will go against what you have learned previously. Our ideas are practiced by thousands and thousands of pool owners across the country because they work.

I suggest you read "The ABC's of Pool Water Chemistry" up in Pool School. It'll give you a start into what we teach. We believe strongly in the need for CYA regardless if your pool is covered or not.

You may choose not to practice what we are about and that's OK. It will be hard for us to suggest how to keep your pool clear unless you make the decision to use our ideas.

Strips are close to worthless at managing pool water. What kit did you purchase?

How can the green water be caused by no CYA so long as my FC and TC are high enough? I'm not understanding that?
Because no CYA means that your FC is, at times, quickly depleted and you let algae get a foot hold. So, the answer is your FC really hasn't been high enough continually.
 
This may be too technical, but see this chart: https://www.troublefreepool.com/~richardfalk/pool/HOCl.htm
With a 0 CYA and a 1ppm FC, the active chlorine level is ~0.5 (think of this as the harshness)
With a 50ppm CYA and a 5ppm FC that Patrick suggested, the active level is ~0.05

So your pool is 10 times more harsh and damaging to skin/hair/suits than if you followed our recommendations. Plus you are having to use more FC.

The CYA does 2 things: 1. Protects the FC from the sun. 2. Buffers the harshness of the chlorine.

It does not sound like you are adding the CYA in the manner we recommend. If putting the CYA in a sock and sitting it in your skimmer basket and occasionally squeezing it is too much hassle ... then I am not sure why you got a pool ;)
 
Okay thanks for the advice! I don't know why I had no algae problems last year doing my no CYA method but I guess its finally catching up to me!

I cannot figure out how to get the CYA to dissolve. I put it in a sock tied to a ladder and would go out and "smush" it every day, and literally 3 weeks later it was barely dissolved at all. I did the bucket technique and stirred it every day and that last months without dissolving. If I put it in my pool straight I will feel it with my feet on the bottom forever. It just doesn't go away! I put quite a bit in last year in the spring and I could never get it to read above 0 when testing for it. Even when I did the expensive liquid kind and did the recommended amount I barely got it to read like 5. I can't imagine how much I'd have to put in to get it to freaking 50! Any suggestions?
 
Hanging from a ladder with no water flow is not what we recommend.

Did you use PoolMath to calculate how much CYA to add. If you have in fact added CYA, it does not usually just go away and you may not have 0ppm of CYA which could mean that your FC level is just not high enough according to the FC/CYA Chart.
 
Yes I used the pool math calculator to determine how much to use (but ended up using more of it over the months because it kept not registering), and the ladder method is something I found recommended on this site. What method do you recommend then for dissolving it? Can I put it straight in my skimmer or something?

What do you mean I may not have 0ppm CYA? You mean the testing strip is wrong or does it sometimes not show up?
 

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I've never heard of Cya not dissolving in the pool, and sorry, I did not mean put it right in the pool. There are very limited products we suggest adding that way and Cya isn't one of them.

I would have to ask how much you added before, and where is the sock full that never dissolved? If it truly did not dissolve, you are the first we've ever heard of.

It is catching you now, and you'll battle this from now on with your current regimen.
 
It did dissolve some just not much, not the full amount by any means. I'm not making it up, I promise it didn't dissolve, sorry if I'm a first on that one.

I don't remember how much I used, it was last year, and I threw the sock away eventually. According to pool math I should use 42oz of CYA by volume to get from 0 to 50CYA. I don't think I did that much because I was using the pool school's recommendation of having it around 30-40CYA but I did whatever it recommended.

Again, what method do you recommend for adding CYA and getting it to dissolve?
 
Lindsay,

CYA takes time to dissolve. I put mine in a sock n tie it shut with a hair tie and put it over the return and manipulate it until it's all out of the sock. It takes around 30 minutes. It clouds in the water. Then a week later, check the levels with an appropriate test kit like the TF100.
 
This may be too technical, but see this chart: https://www.troublefreepool.com/~richardfalk/pool/HOCl.htm

It does not sound like you are adding the CYA in the manner we recommend. If putting the CYA in a sock and sitting it in your skimmer basket and occasionally squeezing it is too much hassle ... then I am not sure why you got a pool ;)

Sorry I just this part about how to add CYA to the pool I missed it in the quick back and forth.

I didn't "get a pool", I moved into a house that happen to have one and am doing my best to take care of it. But ya know if responding to posts without sarcasm is too much of a hassle not sure why you're a moderator ;)

Thanks to those with helpful suggestions, I'll try these and we'll see if it solves the problem!
 
I had a terrible time dissolving the CYA I bought the first year we had our pool. It eventually would dissolve, but took a long time. When I needed to buy more, I bought the brand that Walmart sells, and what a difference. It seemed to melt away when placed in a sock in front of return. Like all things, there are good and bad products.
 
I can say the same thing about CYA granules difference from brand to brand. First time I bought CYA, it was a big tub off of Amazon. The granules were the size of aquarium base rocks, probably 3-4 mm (1/8") in size. Took more than a week to dissolve in a sock suspended in front of the return. The next time I bought it, it was HTH brand from Walmart in a smaller container. Size of the granules was more like fine beach sand, less than 1 mm. Dissolved in just over a day in the sock. Surface area is everything when trying to dissolve solids. Smaller particles, faster dissolving in general.
 

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