cloudy water in endless pool

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maggiecrowe

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Nov 5, 2012
36
Hello from Surrey, England.

I have an endless pool which was installed almost a year ago.
I have been generally lucky with the water and until 2/3 weeks ago I could get it clear if it went a little cloudy.
I also managed to remove combined chlorine successfully in the summer.
Now, I cannot get the water to look pleasant at all. :(
It is cloudy. Also any chlorine I put in seems to instantly vanish.
I suspect that I will have to drain (or partially drain) the pool.
If this is your recommended advice. Is there anything I need to do when adding new water? and how can I prevent future problems?
Any advice would be welcome.

Ph is 7.2
Alkalinity is 110
Free Chlorine 0
Total Chlorine 0
Calcium Hardness 230
Cyanuric Acid 90 (I think this may be a major part of the problem) :?

I use a Taylors test kit which I understand to be one of the best.

Thanks
Maggie
 
Welcome to TFP.

Which model test kit do you have?

The only way to ensure your pool stays clean and sanitary is to keep FC in it in relation to the CYA 100% of the time. What has happened is that at some point you've let the FC get too low for the CYA.

My recommendation is to drain about half the water and refill with fresh to get the CYA down. Then you'll need shock the pool with the new CYA level as the reference point. Once you've finished the shock process, if you'll keep the FC at the level recommended here for your CYA you won't have this problem in the future.
 
That kit is going to be a little bit of a problem. As you are aware, you can only test with DPD up to 5ppm for the FC. To perform the shock process correctly as described in Pool School, after you get the CYA down around 50ppm, you will need to accurately maintain the FC level at 20ppm.

To do this, you need to add the FAS-DPD chlorine test to your kit. It is the Taylor K-1515.
 
Ah! Now the Taylor kits are difficult (impossible) to get hold of here, and postage costs from the US make it impractical to buy direct.
The one I have came with the pool.
I can get hold of reagents for the test system though, so maybe there's a way around it?

I'm new to this and the advice on the kit states to maintain FC between 2-4 on the colour chart. This has a range from 0-.5 up to 5-10
Please can you explain how that fits with 5ppm & 20ppm.
I will also take another look at pool school.

Thanks
 
Most recommendations would not take into account your CYA level is at 90. CYA significantly reduces the active level of chlorine in your pool but also is needed to protect the chlorine from loss to sunlight so this is a balancing act. We recommend 30-50ppm for a non-swg pool. The range on your tester going from 5-10 I believe is up to 5ppm on Chlorine and up to 10ppm on Bromine. You would need to be able to test 4x higher than that.

Here are some helpful links for you

pool-school/pool_water_chemistry
pool-school/chlorine_cya_chart_shock
pool-school/shocking_your_pool
 
The test kit instructions do not take the CYA/FC relationship into account. The 2-4ppm recommendation they make is really based on having no or very little CYA in the water ... this is extremely harsh on skin and clothing. The CYA acts as a buffer to lower the amount of actual "active" chlorine in the water as well as protecting it from the sun.

If you read through the articles in Pool School a couple times it will start to make sense.

Your kits test for chlorine OR bromine in the same vial. You have a chlorine pool, so you just ignore the larger scale that is for bromine. So your chlorine test only goes from 0-5ppm.

Looking at the Chlorine CYA Chart in Pool School. You can see that with a CYA of 90ppm, the MINIMUM your FC should ever be is 7ppm (which is above what you can test) and the shock level to use while clearing up algae is 35ppm (very high). Thus the recommendation to replace the water to get the CYA into the 30-50ppm range we recommend. In the chart, you can see when the CYA is 50ppm, then the minimum FC level is 4ppm (hard to distinguish on your DPD test 4ppm vs 5ppm right?) and then shock level is a more manageable 20 ppm.

The key to maintaining the pool is understanding the different chemistry and required chemical levels and then testing accurately and only adding what you need to into the water. To do this for FC and CC, the FAS-DPD is the ONLY test that works. You should be able to get it in England, there are a few posts about where to find the kits in Europe ... I will see if I can find them.
 
Here is what a different member found. Much of this info is in regards to a full test, but you are only needing to add the FAS-DPD I think ... at least could give you an idea of companys to contact:
pool-test-kits-in-europe-what-i-learned-so-far-t52074.html?hilit=test%20kit%20europe

This person might be able to get you some extra of the powder reagent:
palintest-dpd1-10g-powder-5-inc-postage-to-uk-fas-dpd-t53139.html?hilit=test%20kit%20europe

Sounds like the Palintest SP300 might be easier to get than the Taylor K-1515.
 
Thanks this is starting to make sense :lol:

I looked at the chart and I think I understand - chemistry isn't my strong point :?
(My teacher at school asked if I was any good at French and shook her head knowingly when I admitted that my French grades were similar to my Chemistry grades :roll: )
I'm a mathematician so at least I can do the sums :cool:

If I understand correctly I need to
1.Remove half the water, then add new water
2.Test CYA
3.Shock to achieve CYA of 50 (I believe I can find how to do this in the pool school - not sure what the FC 20ppm means? - but saw advice about amount of chemicals to add)
4. Maintain FC at 7ppm once the CYA is stable

Have I grasped it? :?
 
Keep reading ... you are still a little mixed up ;)

1. Remove 1/2 the water and add new water
2. Test CYA and confirm it is in the 30-50ppm range
3. Follow the shock process with a shock FC level of 12-20ppm (depends on your CYA level ... see the chart)
4. Once you pass the 3 tests to stop the shock process, maintain the FC above the minimum for your CYA level at ALL times

Generally in maintenance mode, people are adding bleach (liquid chlorine) every 1-2 days to stay above the minimum.

What have you historically been using to maintain your FC levels? {Probably should have asked this up front, as a complete change to your normal maintenance might be required} Realize that any solid form of chlorine is have side-effects which become problematic eventually.
 

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OK.

I have been using a chlorine concentrate powder/granules.
I have just bought a different brand (as the company closest to where I live doesn't stock the product I was using) :)
The difference in the suggested level of application between these two products is enormous. (100g versus 15ml to achieve the same thing)

I think as a newbie at this I will take one step at a time and make contact as I reach each stage of the process.
Would that be appropriate?
 
That explains the high CYA reading. The product you are using not only adds CYA, but copper too and you do not want to add metals to your water. Liquid chlorine would be your best choice :goodjob:
 
Yup, Dichlor products add CYA very quickly ... and just will not work for any length of time keeping your pool clean because the CYA rises so fast.

For every 10ppm of FC added (which gets consumed by organics and the sun), it also added ~9ppm of CYA (which does not go away). If a "normal" pool needs 2ppm of FC / day ... that means in just a week you will have added ~13ppm of CYA. In a month, you would add ~54ppm of CYA (which is more than the total recommended amount).
 
Yup. Any liquid chlorine will work. There are typically varying strengths and there are some fairly simple calculation you can do to determine which are the cheapest $ per amount of actual FC you get.

Over here, it is typical that the 6% bleach comes out to be the cheapest, but that also means you have to haul twice as many bottles to get the same amount of FC ppm rise. Although some pool stores have refillable bottles that are a good deal for 10-12% strength (which is the max we get).

Realize that the higher the strength, the shorter the half-life, so I would not stock up on too much of the 14-15% strength as it will loose strength over a few weeks especially if it is not stored in a cool dark place.
 
It does not matter which you use ... they are the same ingredient. For the same volume, If the 5% is less than 1/3 the price of the 15%, then the 5% is actually cheaper per ppm. If the 15% is not 3x the cost of the 5%, then the 15% is cheaper per ppm.
 

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