Slam with Stabilized granules if i have CYA of zero?

[sentry1]

Hello!

I have a first question for this forum. I need to slam my pool which is 14,000 gallons before I winterise it. Yesterday I got the test kit which allows me to work out my CYA levels and I think they are zero (Not holding FC at all).

So I was wondering, could I use the stabilised chlorine granules that I have to do a slam and raise the CYA levels at the same time?

I will then use the TFP method as i have a load of 11% liquid chlorine. I just thought it mught be good to use up the granules as i have no pure CYA yet.

PH is 7.6
FC is effectively 0
TC is slightly more than 0 but not by much
TA was 110 last i checked.

14k gallon pool - how much of the granules (dichlor I think) should I be using to raise CYA and to shock please?

Thanks so much in advance!

 

[PoolGate]

With the pool closing and no one going to swim in it, you really don't need to worry about cya.

 

[Whynotme]

I would feel much better over winter if my CYA was at proper levels before closing. Wouldn't low or no CYA allow the available chlorine to basically evaporate very quickly, leaving the water susceptible to algae blooms for months? I'm new at this, so if I'm wrong someone please explain why. Thanks

 

[ajw22]

Are you putting a solid cover on your pool at closing?

 

[sentry1]

Thanks for the replies. I’m putting a winter cover over it - not solid. I inherited the cover too and clearly judging by the state of the pool when we got it, it lets lots of debris, insects etc under it. I’ve looked at water filled bags to keep the edges sealed but they are v expensive.

Yes - the reason I thought CYA will be important over winter is that on just over the last week, blooms have begun appearing again. I’m assuming because chlorine got low.

Should I expect the pool just to go green over winter and resign to a big clean up in Spring or should I be chlorinating it every few days under the cover? I’m not sure what’s best/ what’s worth doing?

Any advice in CYA over winter - and whether stabilised chlorine granules will be ok to do this while slamming - would be appreciated

 

[PoolGate]

What is your water temperature? I close based on water temp when my water is below 60. At that temp you won't get any algae.

 

[sande005]

CYA or not, Cl doesn't last for really long times (weeks/months). Very cold water/no or little sun will allow it to be there longer. CYA would also extend the time a bit. But in the end, you are balancing the earlier warmer temps where algae might grow, and trying to get to the period where temps inhibit it (mostly) from growing. Too many variables (species, light, etc) to equate, but I have had growing algae in my pool with temps as low as 45F (7C). Not that it grows very fast, but...
Me? I would add CYA to get that bit of reserve it provides. If you have stabilized granules you could use them if starting from 0 CYA. Just be aware that it will be a constantly moving double target - CYA going up with the SLAM level Cl, which means more granules, which moves up the CYA faster...so you want to test both a lot, and not overshoot the CYA goal. There can be a lag in the CYA readings after addition, so you may want to do granules once a day, then augment with liquid if needed for the rest of the day. Test CYA the next to get your new levels, and repeat as needed. Then switch to only liquid to continue the SLAM until complete. Maintain your Cl at the high end of the recommended range until it gets almost too cold to work outside. Then build it up to SLAM level again just before closing.
If you can get it, frequently recommended here is PolyQuat 60 at closing for long term algae deterrence over the winter. It won't kill it, but will inhibit growth.
Between the two, and opening as early as you can (even if just uncovering to be able to add Cl) and your odds of having a algae free pool in the spring will be very high.

And - cold temps can have an influence on your testing - so if water is below about 60F (15C), warm it up inside before testing...

 

[Whynotme]

CYA or not, Cl doesn't last for really long times (weeks/months). Very cold water/no or little sun will allow it to be there longer. CYA would also extend the time a bit. But in the end, you are balancing the earlier warmer temps where algae might grow, and trying to get to the period where temps inhibit it (mostly) from growing. Too many variables (species, light, etc) to equate, but I have had growing algae in my pool with temps as low as 45F (7C). Not that it grows very fast, but...
Me? I would add CYA to get that bit of reserve it provides. If you have stabilized granules you could use them if starting from 0 CYA. Just be aware that it will be a constantly moving double target - CYA going up with the SLAM level Cl, which means more granules, which moves up the CYA faster...so you want to test both a lot, and not overshoot the CYA goal. There can be a lag in the CYA readings after addition, so you may want to do granules once a day, then augment with liquid if needed for the rest of the day. Test CYA the next to get your new levels, and repeat as needed. Then switch to only liquid to continue the SLAM until complete. Maintain your Cl at the high end of the recommended range until it gets almost too cold to work outside. Then build it up to SLAM level again just before closing.
If you can get it, frequently recommended here is PolyQuat 60 at closing for long term algae deterrence over the winter. It won't kill it, but will inhibit growth.
Between the two, and opening as early as you can (even if just uncovering to be able to add Cl) and your odds of having a algae free pool in the spring will be very high.

And - cold temps can have an influence on your testing - so if water is below about 60F (15C), warm it up inside before testing...

That's interesting about doing SLAM just before closing and using Polyquat 60. I was reading that Polyquat 60 has little to no effecacy at high FC levels. I created a post here the other day asking about just that topic.

 

[ajw22]

That's interesting about doing SLAM just before closing and using Polyquat 60. I was reading that Polyquat 60 has little to no effecacy at high FC levels. I created a post here the other day asking about just that topic.

Algaecide - Further Reading

www.troublefreepool.com

Buckman Labs says that even if the Polyquat is broken down, it is still effective when used as an algaecide. Moderate to high levels of chlorine break down Polyquat but it still only transforms the formula into shorter chain polymers that are still just as effective.

 

[sande005]

I missed the "how much" part of your question. Download the Pool Math app. There you can input your pool parameters and then have it calculate the effect of adding a given amount of dichlor. It will tell you the expected rise in both CYA and Cl.

 

[Mdragger88]

Please be careful and use
PoolMath effects of adding - trichlor & dichlor are acidic so you don’t want to tank your ph & or ta with it.

 

[sentry1]

Please be careful and use
PoolMath effects of adding - trichlor & dichlor are acidic so you don’t want to tank your ph & or ta with it.

Ok. I’ve done a combo of dichlor and liquid 11% over the past couple of days. CYA is now at 55. Ph is 7.5. And FC is somewhere above high above 5 ppm (my testing kit only goes to 5).

I’ll plan on vacuuming and brushing thoroughly over next few days, keeping FC high with liquid and then will look to winterise it all.

I don’t plan on using algaecide.

Anything I should particularly remember? And does anyone have a good idea for edging the winter cover (I can really afford those water bags along the edge - they are expensive and have pretty bad reviews)

 

[Mdragger88]

Without an fas/dpd test its not possible to do the SLAM Process properly or prove the algae is gone. You risk over chlorination and damage or simply not ever reaching slam level.

You can attempt to tether the cover or use buckets or pots filled with something heavy to hold it down. The cover should rest on the water if it is a tarp style.