Pool Chlorine Level Keeps Dropping (Please help! Incurring astronomic costs in chemicals)

[Bill1974]

CYA does not go down by itself. Draining water and replacing is the only practical way to get rid of it. Reverse osmosis can be used, but costly if it's even available. The only other way I have heard of getting rid of it is if the pool basically turns into a swamp the the bacteria or algae consume it and turn it into some this else. There is no easy way to filter it out. Typically it will drop slowly from backwashing and whatever gets splashed out of the pool and is replaced by fresh water.

 

[mgtfp]

CYA degrades very, very slowly. The only efficient way of reducing CYA is draining water.

Even though the algaecide you are showing is the only one (referred to as Polyquat 60) that TFP recommends in some use cases, it will not be efficient in getting rid of already existing algae.

The use cases where TFP recommends Polyquat 60 are cases where the pool has no algae, but FC can't be maintained for a while. For example during a metal staining treatment that requires chlorine removal. Or adding Polyquat when closing a pool for winter. In these scenarios, Polyquat can buy some time before algae gets a hold, but not for a very long time.

Polyquat is not very good at removing existing algae. It may help to slow down things getting worse until a proper chlorine treatment can start, but will not remove the root cause.

 

[Newdude]

+1. Algae grows exponentially and stopping that runaway train is difficult and takes a good amount of time even with high levels of chlorine.

Algecide can't keep up at that point.

Imagine having a fence to keep neighborhood dogs out of your yard. But the gate was open and the dogs got in. Closing the gate with the dogs still inside doesn't help. It's too late. It's kinda like that.

 

[Mdragger88]

Thanks to all of you, I agree that there is no sense in slamming until the CYA is lower. I added some water to the pool (about 10%), but I don't really want to throw any out as long as the pool is clear. I am on a small island where we have to be fully self-sufficient with our own rainwater supply (I know, annoying). Will the CYA come down on its own after a while? Also, please let me know how the algaecide supplements work and if it makes sense to throw any of these in? I have attached an image. At this point in time I told the gardener that he needed to scrub any algae regularly in order to control it for the time being.

Save your polyquat for closing (if that’s something that you do)
Its too late for it now.
Its a preventative at best - not a killer
It will take quite a while for the cya to go down enough though “natural causes”
To get it down now so you can get a handle on your algae you need to exchange approximately 40% of your water with fresh.
Depending upon your water flow rates this could be completed in a day or so.
Check out

Draining - Further Reading

www.google.com

 

[qsch1]

So if I were going to try to slam the pool at a CYA of 90 - 100, (we call it shock), how much chlorox (or chlorine granules without stabilizer) shall I put in daily and for how long?

 

[Newdude]

Download PoolMath and you can see how much of each chemical to add when needed.

chlorine granules without stabilizer

Chlorine is a gas and is stabilized with water (bleach), CYA (tabs) or Calcium (cal-hypo/ powdered shock). So the granuals will raise your CYA or your CH.

how much chlorox shall I put in daily and for how long?

For our SLAM Process you test the pool several times a day and add back to SLAM level each time. The goal is to maintain the target with as many doses per day as time allows. The more time it spends at SLAM FC, the quicker it goes. Your effort makes the difference in 'for how long'.

'How much' is decided at each test. 6 gallons of 10% bleach will get you from 0 to 39 FC to start. But 39 FC will burn off quick in the sun, plus any that consumes algae. It will be costly and difficult to attempt to maintain a 39 FC.

Say you lowered the CYA to 30, your SLAM target you'd try to maintain would be 12 FC, a considerable difference.

 

[Mdragger88]

As @Newdude mentioned, unstabilized chlorine granuals are calcium hypochlorite. This adds calcium along with the fc. The fc gets consumed quickly but the calcium remains & builds (similar to cya).
You didn’t list your current ch level so unsure whether you can withstand an increase. Too much calcium leads to scale.
One thing is for certain though- using cal hypo in large quantities to maintain slam level increases ch quickly. Large additions of cal hypo also have a tendency to cloud the water.
For these reasons you should stick to liquid chlorine for the
SLAM Process

 

[qsch1]

Download PoolMath and you can see how much of each chemical to add when needed.

Chlorine is a gas and is stabilized with water (bleach), CYA (tabs) or Calcium (cal-hypo/ powdered shock). So the granuals will raise your CYA or your CH.


For our SLAM Process you test the pool several times a day and add back to SLAM level each time. The goal is to maintain the target with as many doses per day as time allows. The more time it spends at SLAM FC, the quicker it goes. Your effort makes the difference in 'for how long'.

'How much' is decided at each test. 6 gallons of 10% bleach will get you from 0 to 39 FC to start. But 39 FC will burn off quick in the sun, plus any that consumes algae. It will be costly and difficult to attempt to maintain a 39 FC.

Say you lowered the CYA to 30, your SLAM target you'd try to maintain would be 12 FC, a considerable difference.

Thanks ND, so what do you suggest. How many gallons of chlorox shall I put in to start, and for how long shall I have the level up. Is there an approximate amount of chlorox I should throw in each day leading on from that until I am finished? Bear in mind that my PH (before adding a half gallon of acid yesterday) was at least 8.5 and I do not have a pump that runs 24 hours per day.

I did not do a CH test didnt think it is relevant, I am using rain water.

 

[Newdude]

Sorry I am new at this

Please ask anytime you are unsure of something. If you do something you're unsure of, you risk causing multiple issues. And dont worry, we'll help straighten THAT out too, but it's better for all parties if we only have one fish to fry. So we will happily be patient for anything you need and go over it until youre comfortable.

many chlorox shall I put in to start,

Enough FC to get to SLAM, which is 40% of your CYA level. Say you test 3 FC but need to be 39 FC for a CYA of 100. Then add 36 FC.

This is where you plug the #s in PoolMath to find out. It will often change and you need to change your adds with it. Sometimes your bleach supply changes strength and you'll need more 6% than you did with 10% (etc etc). Poolmath will do the calculations for you when you change the strength added.

for how long shall I have the level up.

You want to maintain (the M in SLAM) the FC as often as reasonably possible. If you're busy away from the pool, do the best you can, but test and add every 2 to 3 hours when possible at first. The more effort you put in, the quicker it goes. For example, you're away at work all day. Test before and after, but put the effort in all evening until bed.

The process still works when life pulls you away, but it takes longer.

 

[Mdragger88]

Thanks ND, so what do you suggest. How many gallons of chlorox shall I put in to start,

You use however much
PoolMath tells you to reach slam level for your cya
FC/CYA Levels
based on the % of your sodium hypochlorite & your pool volume

and for how long shall I have the level up.

Until you pass ALL 3 End of Slam criteria
You are done when:

CC is 0.5 or lower;
You pass an Overnight Chlorine Loss Test
AND
The water is clear.
(Crystal Clear w/no algae dead or alive)

Is there an approximate amount of chlorox I should throw in each day leading on from that until I am finished?

No - every pool & algae bloom is different
You just have to test & feed the pool as necessary until you pass all 3 criteria.
We normally tell people to get 10 gallons to have on hand at the beginning.
The first few days the fc consumption can be quite high so it’s best to be prepared.
Test & replenish fc multiple times per day. The more often you do this the faster you will gain the upper hand.

Bear in mind that my PH (before adding a half gallon of acid yesterday) was at least 8.5 and I do not have a pump that runs 24 hours per day.

You need to lower your ph to 7.2 before beginning slam as outlined in the article
SLAM Process
As during slam the only thing you will be testing is fc & cc

I did not do a CH test didnt think it is relevant, I am using rain water.

If you have a plaster pool you need to ensure your ch is not too low or you could get etching.

What Are My Ideal Pool Levels?

Use our tool to find ideal chemical levels for any swimming pool. Check TFP recommended levels on pH, free chlorine, cyanuric acid, and more.

www.troublefreepool.com

 

[qsch1]

You use however much
PoolMath tells you to reach slam level for your cya
FC/CYA Levels
based on the % of your sodium hypochlorite & your pool volume

I am not seeing how to check this in pool math? Not seeing a slam option? I think my first step is to drop the PH with acid to the level you suggested (7.2) and to check the CH?

 

[Newdude]

I am not seeing how to check this in pool math?

After you set up the basic pool details in PM, close/open the app and the parameter tabs appear. Click on whichever one you wish to adjust and that opens up all those details to select.

I think my first step is to drop the PH with acid to the level you suggested (7.2) and to check the CH?

Yes to adjust the PH. Calcium isn't an issue for now.

 

[qsch1]

After you set up the basic pool details in PM, close/open the app and the parameter tabs appear. Click on whichever one you wish to adjust and that opens up all those details to select.

View attachment 556513


Yes to adjust the PH. Calcium isn't an issue for now.

Thanks yes I am on that page above, but how do I see what I need for the slam level?

 

[Mdragger88]

Click the fc card

Then you will be here

Be sure SLAM is toggled on
Then scroll down and you’ll see this

Adjust your chlorine % to the strength you have & it will tell you how much to use
Hit the log your addition button & it will save it to your logs.
If you don’t have a subscription it will just save the last one each time replacing the previous log.

 

[mgtfp]

I did not do a CH test didnt think it is relevant, I am using rain water.

Just reiterating what Mdragger88 already mentioned as you haven't replied to that yet:

If you have a plaster pool you need to ensure your ch is not too low or you could get etching.

What is your pool surface: Plaster, Vinyl or Fibreglass?

You are correct in your thinking that rain water is not oversaturated with dissolved calcium carbonate so that calcium carbonate scaling is not an issue with rain water.

But the process also goes the other way round: Rain water is in fact undersaturated with calcium carbonate and will pull it out of surfaces it is in contact with when available (as in plaster surfaces).

And should you have used calcium hypochlorite for chlorination in the past then your water could well be already oversaturated with calcium carbonate (the carbonate comes from TA-increaser).

 

[qsch1]

Click the fc card
View attachment 556517
Then you will be here
View attachment 556518
Be sure SLAM is toggled on
Then scroll down and you’ll see this
View attachment 556519
Adjust your chlorine % to the strength you have & it will tell you how much to use
Hit the log your addition button & it will save it to your logs.
If you don’t have a subscription it will just save the last one each time replacing the previous log.

I get it now, thank you! So I ordered ten bottles of bleach and 2 bottles of acid to drop the PH first. I am being told to put 5 bottles inside. Is it enough to try and check the FC in the pool in the morning and evening, then add the bleach level needed to maintain 39 FC? Once that level is maintained I assume I have to do an overnight chlorine loss test, but after how many days do I do that?

 

[Newdude]

Is it enough to try and check the FC in the pool in the morning and evening, then add the bleach level needed to maintain 39 FC?

Yes. The more often you can put it back to 39, the quicker it goes. When you're around at home, 2 to 3 hours each is best, no need for more often than that.

You can also add early, say on a weekend when you have errands to run. Dose before you go and it buys you the next 3 hours away.

Once that level is maintained I assume I have to do an overnight chlorine loss test,

You should see more loss whenever you test at first because there's more to kill. As the process moves along, the FC holds longer between adds.

Once the water is clear with no signs of algae (on the walls or poofing when you brush), you're getting closer and move on to the overnight test. There's no need for them at first.

Scrub every inch of the pool, paying special attention to anywhere algae can hide in plain sight. Ladder rails hold a gallon or two of old water for example, or all up in the guts of thr skimmer.

Also pay attention to your filter because it'll be working overtime capturing all the dead algae. Clean it when the psi rises 25% over clean.

 

[qsch1]

My pool finish is plaster diamond brite. I am going to do another test shortly for CYA and FC, I will also add CH and post it here before I start shocking the look. I got the attached chlorine shock, let me know if this is ok. It seems to need a lot more of this than the chlorox bleach? It says 6 pounds but only 3 bottles of chlorox.

 

[Bperry]

My pool finish is plaster diamond brite. I am going to do another test shortly for CYA and FC, I will also add CH and post it here before I start shocking the look. I got the attached chlorine shock, let me know if this is ok. It seems to need a lot more of this than the chlorox bleach? It says 6 pounds but only 3 bottles of chlorox.

That stuff has calcium in it, so be aware of that. If you’re calcium is very low it’s ok to add it but you don’t want too much calcium in the water.

 

[qsch1]

My pool finish is plaster diamond brite. I am going to do another test shortly for CYA and FC, I will also add CH and post it here before I start shocking the look. I got the attached chlorine shock, let me know if this is ok. It seems to need a lot more of this than the chlorox bleach? It says 6 pounds but only 3 bottles of chlorox.

Ok guys so I have done the 4 of the most important tests again today. FC is still only 1 (same as last time), but then we have algae although the water is clear which explains that. I did a calcium hardness test which is also high. That is 750 in total. Then I did the PH it’s a bit hard to say if it is 7.8 or 7.5, I personally would say 7.8 as it is a bit brighter. The CYA is 90 now as we added some fresh water. Shall I start slamming the pool now or shall I get the PH lower? What are your recommendations I assume not to use the granules (Aqua Org Plus) above as my calcium is so high already, is bleach better in that case? What about this product I have attached (70% unstabilised chlorine). I am trying to log the tests in the app but it would not let me?