very cloudy water after a day of unintentional experimenting

[ATATX]

Hello, I'm very new to this forum.
I'm also relatively new to having a pool (8 months now).
We converted to a saltwater pool a couple of months ago and have had very few problems.
The only problem is that our pH keeps drifting up, so we need to add muriatic acid regularly.

Until today.
My husband asked me to look into why our pH keeps creeping up.
I did a test this morning using TF-100 kit, basic Taylor kit and Leslie's test strips (so that's why there are a few numbers for some items)

pH 7.8 // 8.0
TA 150 // 180-240
CH 850 (?? the reagent in TF-100 kit looked cloudy, so I'm pretty sure this was wrong, last reading few weeks ago was 225)
borate ~ 50ppm
CyA >100ppm // 100-150
the Cl was on the low side, but that's not part of the problem.

I told husband that our pH and TA were too high, hence the pH upward drift.
I said to add muriatic acid, and maybe add some more to lower the pH to 7.2 and then aerate, to also reduce the TA.
He used a pool calculator, gives in a wrong number and adds 2 (!) gallons of muriatic acid to the pool and leaves for work.

I test the water in the afternoon:
pH 6.2
TA ~100
I try to aerate for hours, with little change in the pH, so I finally tell him to go get some soda ash to raise the pH from this frightening 6.2 number.

He adds 10 lbs of soda ash. Yes, he does things drastically...
The pool becomes super cloudy.
We keep on aerating. After a few hours, the pH is 7.2 and TA 120.
These numbers seem okay-ish.
Only we have a super cloudy pool now.
You cannot see past the first step.
I'm sure it's oversaturated in carbonates, but...
what do I do now?

Thank you for your help.
newbie on this forum

 

[jblizzle]

Welcome to TFP!

So .... I think one or the other should be in charge of the pool ... seems like you

If it is just from the soda ash, it should clear up by just running the pump.

Btw, a SWG aerates the pool too, so that with the high TA is why your pH keeps rising.

The bigger problem is that your CYA is too high thus your Free Chlorine is too low ... this could cause cloudiness in the form of algae.

 

[ATATX]

Thanks so much, Jason.
After running the pump most of the night, the pool is much clearer now, but still far from ideal.
We'll keep running the pump.

We know our CyA is too high, it's been high ever since we bought the house, but I guess converting the pool to a saltwater pool made this more of an issue.
The only way we know how to reduce CyA is to dump some of the water and add fresh water. We're in Central Texas, it's August, we're in a drought.
It just doesn't seem to be the right time of year to do so... How big of an issue is it?

My husband and I made a deal - from now on, he's in charge of all the mechanic parts of the pool, I'm in charge of the chemistry ;-)
Ann

 

[timerguy]

Actually, converting to a SWG helps your high cya a bit. You won't have to replace quite so much water.

 

[jblizzle]

Well, the higher the CYA, the higher the FC level you have to maintain ... and also the MUCH higher the FC level that is required to SLAM the pool if you have algae develop.

You have to get a better number for the CYA. Do the dilution test as described in the Extended Test Instructions.

 

[timerguy]

Where's your FC /CC numbers?

 

[RobbieH]

Have you performed the diluted CYA test to see where you really are at? Dilute half pool water with half tap water, run the CYA test, then double the result.

 

[adrob2]

I'm a newbie, but I would think with CYA of over 100 your SWG may not be able to keep FC high enough to avoid algae growth. Looking at the CYA-FC chart you would need FC held at 12 ppm for CYA of 100. If you could get it down to 80 that would reduce your target FC to 6 and greatly reduce the demand on your SWG.
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

 

[jblizzle]

I'm a newbie, but I would think with CYA of over 100 your SWG may not be able to keep FC high enough to avoid algae growth. Looking at the CYA-FC chart you would need FC held at 12 ppm for CYA of 100. If you could get it down to 80 that would reduce your target FC to 6 and greatly reduce the demand on your SWG.
http://www.troublefreepool.com/content/128-chlorine-cya-chart-slam-shock

You can not mix the tables. For a SWG with CYA of 100ppm, the minimum FC would be 5ppm, so the target would be about 7-8ppm. And actually, with a higher CYA, the SWG will not work as hard because the FC is more protected from the sun. The problem with high CYA levels arise when a problem develops and you need to SLAM the pool. Also, if the CYA is too high and you need to keep the FC above 10ppm the pH test becomes invalid.

Our CYA recommendations are a balance between the added protection of the FC from the sun and the risk of very high FC levels required for a SLAM.

 

[ATATX]

I did the dilution test - we're at 140 for CyA.
I always thought we were just a bit over 100, cause the pool test results we get back from Leslies says 100.
So.. I need to drain half my pool? Or 43% of it, to get to 80 ppm CyA (=(140-60)/140)?
Can we use the 3500ppm salt water on our plants?

Any other considerations for draining half the pool?

Thank you again, Jason for that target 7-8ppm FC number. I'll use that for now. The table only goes up to 80ppm CyA, so I never knew what the target should be.
We never had algae issues, and never had to SLAM the pool. Thank God for that!

Ann



What do I do with

 

[jblizzle]

That target was for a CYA of 100ppm ... Since you are at 140ppm, the minimum is 7ppm, so your target is 9-10ppm. AND this assumes that there is nothing that has already start growing in the pool which would required the SLAM process.

The minimum FC level is 5% of the CYA value for SWG pool. For non-SWG pools, it is 7.5% of the CYA value. It is the minimum that is the most important number.

BTW, most CYA tests max out at 100ppm ... that is why pool stores will always report 100 or 99ppm when in fact it is likely higher.

 

[ATATX]

I just got that from rereading your last post

When we bought the house, the pool guy that was taking care of the pools aid, "yeah, its' a little high..."
The pool store guys said the same.
It's just now that I actually understand the relation between CyA and Cl.

Thanks!
Ann

 

[RobbieH]

The pool store can't measure over 100 either, and also the CYA test is one they typically get wrong.

Regarding putting salt water on your plants, I hear it can be an issue for tender plants, but I've never had a problem putting it straight out onto my St Augustine lawn.

 

[one_knight4u]

Hello ATATX (Ann) Welcome to TFP and we are glad you are here,

Can we use the 3500ppm salt water on our plants?

Any other considerations for draining half the pool?

I would not drain the water on the plants. Your concentration of water is alot lower than that of the ocean but vegetation will not take much salt water before killing it(of course that depends on the plant).
I have on occasion cut down some hardwood trees that would sprout from the stump. A one inch spade drill bit with 4 tablespoons of table salt will keep most any tree from regrowing. When it rains it soaks the salt water into the stump.

Im not sure if you have any regulations against dumping salt water in the storm drain if you live in the city, or in a drainage ditch. You might have to call the powers that be and check on that one.

 

[RobbieH]

When we cleared out a tree that had grown against the house and had sprouted roots into my plumbing, we dumped a whole bag of that solar salt onto the new plumbing to keep any roots from coming back.

 

[ATATX]

Success!
We drained ~45% of the pool, refilled overnight, did a rough calculation on how much salt we needed, and our new numbers are:
salt 3400 ppm
pH 7.5
FCl 3.5
CC 0.5-1 - don't know where that came from, tap water??, we never had it before.
CH ~ 750, but I need new reagents for this test
TA 150 - still would like to get that lower
CyA 65 - Yay!

Just wanted to let everyone know it was rather easy to do.
I did call the municipality to check whether it was okay to dump the water.

Thanks for your help!
Ann