SLAMing a SWG pool

[surfbabe]

OK, so finally the pH is at 7.2
I will put in the 10ppm FC now.

Question: how long will it take for the CYA to register on a test? Richard320 mentioned that I could start the SLAM at the same time as adding the cya but surely I need to make sure that it's up to 30ppm? If I add 30ppm worth of cya and they have 20ppm already which isn't registering, then 12ppm FC won't be enough.
If we can't assume that the CYA is 0 then obviously I am going to add it a bit at a time. First lot will be 10ppm worth of it and see if it registers on the test, if not, then another 10ppm and if needed another 10ppm. That sound about right?

 

[jblizzle]

Behind the scenes we are doing some experiments to figure out just how quickly the CYA shows up.

The liquid is believed to show up practically instantly on the test (just circulate for an hour). The granule CYA, seems to be showing up within 1-2 days (we used to say 7 days) if you follow the recommendation to dissolve it out of a sock (in the skimmer or in front of a return jet).

 

[surfbabe]

Ok, so I've been doing the 10ppm for 10 minutes test. At first, the drop was down to 2ppm, I've continued and the last couple of time the drop was 1ppm. I've gone through about 4 gallons of bleach.

Is this ok for me to add the CYA now or should I carry on until there is no drop at all?

 

[Richard320]

Ok, so I've been doing the 10ppm for 10 minutes test. At first, the drop was down to 2ppm, I've continued and the last couple of time the drop was 1ppm. I've gone through about 4 gallons of bleach.

Is this ok for me to add the CYA now or should I carry on until there is no drop at all?

If you have the situation where all your CYA broke down into ammonia, you'll have really high CC. Do you?

If you're only losing 1 ppm FC in ten minutes and the CC is low, like under 2, then you're ready to add some CYA and raise the shock level.

 

[surfbabe]

thanks Richard!

it took another couple of 10 minutes... but finally FC loss was under 1ppm and CC was 1.5

I added 50 oz of liquid cya which should be about 9.6 ppm. It's now 35 minutes since I did that so I'm going back to test the CYA level and probably to add another 10ppm.

 

[kimkats]

WOW! What a great thread! surfbabe you have some of the finest on TFP helping you! Listen to them and your neighbor's pool will be as clear as yours!

Thanks everyone that has jumped in to help!

Kim

 

[surfbabe]

I know Kim, these guys are just amazing!

When I first tested the CC this evening after Richard told me to do it, it was at 4.5ppm.

Can somebody explain to me what is meant by the CYA breaking down to ammonia? Why does that happen?

 

[jblizzle]

The belief is that there is a bacteria that gets into the water when the FC drops to 0 for long periods of time (like over the winter) which is able to convert the CYA to ammonia. To get rid of the ammonia you have to use large amounts of chlorine before the chlorine level will start to hold.

 

[surfbabe]

The belief is that there is a bacteria that gets into the water when the FC drops to 0 for long periods of time (like over the winter) which is able to convert the CYA to ammonia. To get rid of the ammonia you have to use large amounts of chlorine before the chlorine level will start to hold.

So that sounds like that was a problem here.

So far, I've used about 5 gallons of bleach and I haven't started the SLAM yet. I added liquid CYA which should have been about 10ppm but it still didn't show up in the CYA test, so I've added another 60 oz and I'll test again in about 30 minutes.

The water already looks loads better. As we added the first 10ppm of FC and brushed the sides of the pool, you could see the algae going white. The pool is no longer turquoise - just a cloudy blue with a hint of turquoise.

 

[jblizzle]

You are certainly making progress

I guarantee those 5 gallons cost way less than you would have spent if you went to the pool store to be at this point

 

[surfbabe]

Just tested the cya after the second addition of 10ppm and it was about 20 ppm, maybe just under. They really didn't have any cya in there at the beginning. I added another 60oz or so (the rest of the bottle) and added 8ppm of FC to bring it to about 13ppm. It is now dark and rainy in Austin......I'll be going back in the morning.

They will need to buy some more cya and I guess I should ask them to get powder. I'm hesitating on that one just in case the cya is under 30ppm in the morning and I want to raise it up whilst continuing the SLAM.

I was talking to them about the pool. They bought the house in October and the pool was a slimy green swamp. They ended up getting about 4/5 different pool companies in to try and fix it, they've spent hundreds of $$ and the pool was turquoise all through the winter until now. It hasn't been emptied and so I'd like to think that the pool companies did make sure there was CYA in it and that as previously mentioned the CYA has been used up by bugs.

So far, the cost to them has been about $40 in bleach and $35 for the liquid cya. They will be buying some tests - I think they will need a test for salt, chlorine and pH.

 

[Texas Splash]

If you go back to the store today, don't feel obligated to buy the $35 liquid conditioner. You can still simply buy the granule stuff at many places that sell pool products (i.e Wal-Mart, Home Depot, Lowes, etc) and buy granule stabilizer (4 lbs for about $16.) Once you put the required about in a sock and start soaking/dissolving, consider it all but in there and adjust your FC up accordingly. Might save you a few bucks.

As for the pool history, the only thing "unknown" is what those pool companies may have done or put in the water that's a mystery. Hopefully it wasn't any algaecides or fancy products that contain metal. That would be another chapter in this story. For now, bleach, bleach, and more bleach. Hang in there.

 

[surfbabe]

Good Morning Everyone!

Pool looks noticeably better this morning than yesterday...

I tested the CYA and it showed 40ppm - slightly higher than we wanted. I had added sufficient liquid cya to go to 30ppm in a 15000 gallon pool which is what they told me they "thought" it was - no documentation. So either the pool is smaller than they think or there was some cya in there still or the cya took longer to show on the test? I'm guessing the pool is a bit smaller. Its a funny sort of fat 8 shape with steps and a gradient that I was really hoping to avoid having to measure!!

This morning's FC was down about 2ppm overnight and is now 11ppm.

I've revised the shock level of FC to 16ppm since cya is higher than 30

I've added 5.5ppm FC to take FC to 16.5 ( It equaled 121 oz or 1 bottle...)

 

[jblizzle]

Sounds like you are progressing well.

 

[surfbabe]

just measured the FC and CC after topping up to what I thought was 16.5ppm..

FC = 21
CC =1

The pool is definitely smaller than the 15000 gallons.
Is there an easy way to work out the volume in gallons?

121oz gave a 10ppm rise in FC , not the 5.5 I thought it would....
a quick play on pool math suggests that their pool is actually about 9000 gallons according to the rise in FC.
Am I missing something here?

 

[ping]

It could be several things, the strength of chlorine is not what you think it is, the pool size could be smaller than 15,000 gallons, and/or your default strength of chlorine in PoolMath is wrong.

I'm getting that you have 6% in PoolMath for the chlorine strength to get 5.5ppm rise in FC for 121 ounces of chlorine, but if the actual chlorine is stronger it will add more just like you got with the 10ppm rise.

 

[surfbabe]

I've checked the pool math chlorine strength and I have it at 8.25 % I'm using regular clorox at 8.25%
"I'm getting that you have 6% in PoolMath for the chlorine strength to get 5.5ppm rise in FC for 121 ounces of chlorine, but if the actual chlorine is stronger it will add more just like you got with the 10ppm rise."

Ping, I'm sorry but I don't get what you mean.

for a 15000 gallon pool, 8.25% chlorine strength 121 oz - pool math gives me a 5.3ppm rise.
for a 9000 gallon pool 8.25% chlorine strength 121 oz - pool math gives me an 8.9ppm rise

considering that the cya went to 40ppm on the amount that I thought would get me to 30ppm, I think that the pool volume is smaller...

 

[jblizzle]

Split the difference and set the pool volume to 12000 gallons and see how that goes

 

[ping]

I've checked the pool math chlorine strength and I have it at 8.25 % I'm using regular clorox at 8.25%
"I'm getting that you have 6% in PoolMath for the chlorine strength to get 5.5ppm rise in FC for 121 ounces of chlorine, but if the actual chlorine is stronger it will add more just like you got with the 10ppm rise."

Ping, I'm sorry but I don't get what you mean.

for a 15000 gallon pool, 8.25% chlorine strength 121 oz - pool math gives me a 5.3ppm rise.
for a 9000 gallon pool 8.25% chlorine strength 121 oz - pool math gives me an 8.9ppm rise

considering that the cya went to 40ppm on the amount that I thought would get me to 30ppm, I think that the pool volume is smaller...

Your're right, I'm wrong on the math, sorry about that. Use 12,000 gallons for now like jblizzle suggested.

 

[surfbabe]

I just measured FC and CC again..
"Oh good" I thought, "FC is holding steady"... then I remembered that the SWG is on!! The plan was to switch it off tonight for the OCLT.
CC is at 1.ppm
FC 21ppm
Since the FC is a bit high for the 40ppm CYA, should I switch off the SWG and let the FC go down a bit?
It's a Jandy SWG with 2 buttons on the front, one is on/off. I guess I just press that one?