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

[mgtfp]

You can use a 5ml sample with 1ppm/drop, no problem, that's what we usually recommend during a SLAM.

I was just suggesting that in your case with 70ppm CYA and the resulting high SLAM-FC, plus your difficulty in getting reagent replacements, it could make sense to use a 2.5ml sample (or a 5ml sample of 50:50 FG diluted pool water) with 2ppm per drop. To avoid running out of reagents before you're done. Just go more precise when doing the OCLT.

 

[mgtfp]

You are saying to use 2.5 pool sample water 2.5 rain water and each drip will be 2 ppm?

You can use either just a 2.5ml pool sample, or mixing a larger amount of pool and rain water (say 100ml each) and take 5ml from that. This may be easier to measure than 2.5ml. But there is no point in measuring 2.5ml pool water and measuring 2.5ml rain water and mix them.

 

[Mdragger88]

So basically this is what happened the first day. After about 3 hours I was asked to put in another 3 gallons. We brushed it a lot then after about 3-4 hours again I was asked to put in another 4 gallons. It’s the end of the day now, shall I do more tonight or wait until the morning? We scrubbed it well, and it looks quite clean. I think the filter must be pretty dirty now so asked the gardener to come tomorrow to change that. I am down to 4 gallons left from 20. I was told that 10 gallons of 15% should be enough. They are only 5%, not 15. I assume I need at least 8 more gallons what are your recommendations?

10 gallons of 10% to start with (have on hand) was what was recommended for you to aquire.
Each slam takes whatever it takes to complete- it’s different for every pool.
You’re going the right direction- just keep going
& get your hands on some more liquid chlorine/bleach.
Also, understand that you’re using only 5% bleach so it takes twice as much to do the same thing as 10% strength. You’re gonna have alot of empty bottles. It is what it is.
In the US many are able to source 10% liquid chlorine in refillable jugs at pool stores or janitorial/pressure washing suppliers for cheaper than using household bleach. Hopefully you’ll be able to find another supplier. If not that’s ok too.

 

[sande005]

Just to recap - the bleach is being used to kill the live algae At first there is a lot of algae, so the bleach gets used pretty quickly and more has to be added. As time goes on, there is less and less to kill. Meaning longer times between needing to add more bleach. Until you finally get to that SLAM point where there is no more algae, and therefore nothing to use up the bleach. The initial algae load, amount of sunlight the pool gets, etc. all factor into the bleach use, hence why it is hard to guess ahead as to "how much". But if all is going as it should, your trips to buy more will be less and less as the SLAM process progresses. Once complete, then your SWCG can take over the job of adding chlorine.

 

[qsch1]

Hello

10 gallons are a good start. That's enough to get up to SLAM and see how quickly you go through it. And then buy more. Every SLAM is different, you have to go with the flow. The more often you check and get back to SLAM level, the faster the overall process, but there's also no point in getting paranoid. I would check one more time once it's dark.

In your case with limited reagent access and relatively high SLAM level, I would even consider using a 2.5ml sample (measured with a syringe) and have 2ppm per drop resolution for the test and dose. Just assume for the dosing that FC is 2ppm lower than you tested to calculate the next chlorine top-up. You might overdose slightly, but wasting a bit of chlorine is in your situation better than running out of reagents mid-SLAM, I'd say. Or make a 50:50 mixture of pool and rain or distilled water and take a 5ml sample of that to get 2ppm per drop.

Hi, so it is now slowing down today the chlorine consumption and the pool looking very nice. I had one question, when checking the CYA, should I do it indoors or outdoor, I know I should have my back against the sun, but wasn't sure as I assume the result would also depend on how much light / bright it is in the area.

 

[mgtfp]

Generally outside. It's usually less important to nail the CYA test down to the last ppm than doing it reproducibly.

 

[qsch1]

Update: It seems the chlorine level is holding up now, and from this afternoon until now it has not dropped. The CH is quite high (850) that's the only one, and I am slowly getting down the Salt which is now 4400, whilst TA (70), PH (7.2), CYA (75 - 80) seem to be in the ideal range. What should I do with the CH, or is that not as important? I think I am going to do the Chlorine Loss Test tomorrow night.

 

[Mdragger88]

Update: It seems the chlorine level is holding up now, and from this afternoon until now it has not dropped. The CH is quite high (850) that's the only one, and I am slowly getting down the Salt which is now 4400, whilst TA (70), PH (7.2), CYA (75 - 80) seem to be in the ideal range. What should I do with the CH, or is that not as important? I think I am going to do the Chlorine Loss Test tomorrow night.

Great news about the FC
Keep going until you pass all 3 end of slam criteria.
The high ch is not ideal but it’s manageable for now until more water can be exchanged. So long as you don’t add any more ch containing products & your fill water has low ch then as you refill your water lost to splashout it should gradually decrease.
After the slam process is complete you will want to be sure & manage your csi to reduce the scaling risk.

Calcium Hardness - Further Reading

www.troublefreepool.com

 

[mgtfp]

That's great news about your chlorine starting to hold. Well done!

Are you testing pH with an electronic meter or the drop test from your kit? I'm a bit surprised to see a pH of 7.2 while at Slam level. Above FC 10, the chlorine starts to interfere with the pH drop test and usually turns it purplish, making pH look high.

 

[qsch1]

Hi I threw more acid in to keep it low in the recommended amount you all said of 7.2, it was about 7.8 up to that. What I don’t understand yesterday afternoon the FC was 29 and then in the evening it was the same 29, this morning around 9 am (after 2 hours of sun and after brushing the pool) it dropped to only 22? I thought it would be only a few points less because of the result yesterday evening but not a whole 7? Is this normal due to the algae still not completely gone or is there an issue with my SWG?

 

[Bperry]

Hi I threw more acid in to keep it low in the recommended amount you all said of 7.2, it was about 7.8 up to that. What I don’t understand yesterday afternoon the FC was 29 and then in the evening it was the same 29, this morning around 9 am (after 2 hours of sun and after brushing the pool) it dropped to only 22? I thought it would be only a few points less because of the result yesterday evening but not a whole 7? Is this normal due to the algae still not completely gone or is there an issue with my SWG?

Do NOT test or adjust pH during the SLAM. Your SWG also must be turned off or the OCLT won’t be accurate.

 

[qsch1]

Do NOT test or adjust pH during the SLAM. Your SWG also must be turned off or the OCLT won’t be accurate.

Ok in relation to the PH, I may have done it just before starting the slam. How do I turn off the SWG? Just switch off the Auto Pilot computer or pull out the cord?

 

[mgtfp]

Hi I threw more acid in to keep it low in the recommended amount you all said of 7.2, it was about 7.8 up to that. What I don’t understand yesterday afternoon the FC was 29 and then in the evening it was the same 29, this morning around 9 am (after 2 hours of sun and after brushing the pool) it dropped to only 22? I thought it would be only a few points less because of the result yesterday evening but not a whole 7? Is this normal due to the algae still not completely gone or is there an issue with my SWG?

Once the sun hits, FC starts going down, not sure if sun in the tropics is already strong enough in the morning to do that much of an effect.

I suspect that there is still algae on the walls and brushing removed the protective layer and brought the algae into the water so chlorine could react quite quickly with it.

Keep going and keep brushing.

 

[Bperry]

Ok in relation to the PH, I may have done it just before starting the slam. How do I turn off the SWG? Just switch off the Auto Pilot computer or pull out the cord?

If There’s a cord to unplug, you could do it that way, unless someone else can comment on your specific system. The chlorine needs to hold without any being added including by the salt Chlorinator.

 

[Mdragger88]

You can simply turn your production down to 0%
See page 7

https://images.inyopools.com/cloud/documents/pool-pilot-digital.pdf

 

[qsch1]

You can simply turn your production down to 0%
See page 7

https://images.inyopools.com/cloud/documents/pool-pilot-digital.pdf

Ohh yea I forgot that! Sometimes my computer screen goes haywire, if I plug out the connections and put them back it usually goes back to normal. I will post a picture…BTW I tested 29 free chlorine this afternoon around 1 and now at 6 it only dropped to 28.

 

[Bperry]

Ohh yea I forgot that! Sometimes my computer screen goes haywire, if I plug out the connections and put them back it usually goes back to normal. I will post a picture…BTW I tested 29 free chlorine this afternoon around 1 and now at 6 it only dropped to 28.

If your SWG is still powered on you can just wait to do comparison testing until it’s powered off as it doesn’t mean a whole lot if it’s still powered on.

 

[qsch1]

If your SWG is still powered on you can just wait to do comparison testing until it’s powered off as it doesn’t mean a whole lot if it’s still powered on.

Remember my pump is solar driven so it doesn’t run overnight anyway. So from when I tested yesterday evening after the sun went down to this morning before the sun is up it was not running.

 

[Bperry]

Remember my pump is solar driven so it doesn’t run overnight anyway. So from when I tested yesterday evening after the sun went down to this morning before the sun is up it was not running.

Ok, that’s good, just don’t get fooled by it once you get close to finishing.

 

[qsch1]

I just checked the FC in the pool this morning and it is now 22 from yesterday evening where it was 28 (although it only went down 1 or 2 points over yesterday afternoon). So it’s going down quite a lot overnight still although the pool was already quite clear two days ago. I put another two gallons of liquid chlorine in and one quart to get it back to 2.9. Is this normal after 3-4 days?