Newbie with high CYA issue

[Summer555]

TF100 results:

FC 3.5
CC 0.5
PH 7.5
TA 170
CH 160
CYA 150 (I used 50/50 solution and 4 of us tested result of between 70 and 80 so I went middle ground)
Copper 0.2 (pool shop, I added algaecide and then they had me add it again, reduced from 0.4 through dilution I guess)

Pool is cloudy blue

It was very green, couldn't hazard a guess how much I shocked it with but my CYA went up by around 100 according to pool test shop, one of the testers is actually quite good so I used her original result as a guideline.

Biggest hurdle I have is trying to reduce CYA levels, I live in a rural area where having to cart water in could possibly cost me close to $1000, I am on tank water. I believe I have reduced CYA levels a little by keeping pool solar cover on at all times when pool is not in use, it's made a huge difference in reducing evaporation significantly. I have been topping up pool (around 70gallons every day, have to do it by bucket). We've had a bit of rain over Nov/Dec to help dilute. I am also redirecting some water catchment to go straight into the pool. I am aware that this is not a recommended way of doing it, but it's the most economical for me.... 12.5% bleach is a lot cheaper than water! Over winter this will dilute a helluva lot as we get a fair amount of rain, conservative amount is 8-9k gallons of water going in.

Okay, so is my plan of attack to shock straight away and hold until I pass the overnight test? Calculator says 33, are these vinyl liners strong enough for this?
Should anything else be adjusted?
Will the cloudiness reduce or go away with what everything else is reading, or is it just taking a while for my filter to pick things up... the cloudiness is reducing ever so slowly. Todays FC is lowest it's been, generally have been aiming to keep it around 10.
Will I have to keep the cover off while everything is going on, 99f today, sun is extremely hot and it's very windy so will keep cover on today/tonight and start afresh tomorrow as we have 4 or 5 days of lower temperature?

Absolutely awesome site, it's a shame I had to damage my water in order to find you. But now, I have seen the light and no more pool shop with their wildly bouncing results. Thank you!

 

[zea3]

Hi, welcome to TFP!
Since you have a good rainy season, before every big storm is expected you should drain off a couple of inches of water. It may take a while but eventually you will be able to reduce the CYA level in your pool.

You can use your cover during the shock process if you want. The shock levels may shorten its life a little bit. You may notice a little color fade in the liner, but overall chronically low pH will cause more harm to the liner than high chlorine levels.

Continue the shock process until you pass the overnight test, the water is clear, and CC is .5 or less. If you find you pass the overnight test and the CC is less than .5 for two or three days but the water is cloudy then you may need to keep running the filter 24/7 and clean it frequently. You can also turn off the pool overnight and see if all the debris settles to the bottom and carefully vacuum it out.

 

[Summer555]

Thanks for your reply.

Ended up leaving cover off overnight and doing OCLT test..

PM AM
FC 13 10
CC 0.5 0.5

Will start shocking today. Wish I had taken a before picture but this it yesterday (if it works), kids had jumped in and made it more cloudy. Left pool cleaner in for point of reference.

 

[Summer555]

30 minutes after chlorine addition and I noticed a huge difference. About to go do my first check.

I was re-reading the instructions for the tests and realised that I didn't quite follow instructions properly. Alkalinity test, I forgot about wiping the bottle after each drop until I got to the last 2 or 3.
And the CYA test, I followed the instructions from the test kit where I mix, wait 30 seconds and then shake again... other instructions state to shake for 30 seconds. Will these have made a big difference to what my results should have been?

Thanks for your help.

 

[Bama Rambler]

For the TA test, only a select few new bottles have the static issue and that's the reason you need to wipe the tip. If your kit is not brand new or oyu don't have the static issue, wiping the tip won't affect the test. You can run it again, wiping the tip and see if there's a difference.

As for the CYA test, either set of the instructions work. It's usually easier to shake it, let it sit, then shake it again, instead of shaking it for the entire time. Doing it either way won't affect the test enough to matter.

 

[Summer555]

Argh! I got the FC balance up to 35 at 6.30pm and thought that would cover me for overnight allowing for a slight drop but as 9pm it had dropped to 30. Left it at that as I wanted to the the OCLT test overnight, in hindsight should've have just bumped it back up.

PM
FC 30
CC 0.5

AM
FC 24.5
CC 1.0
Water is pretty close to being clear. Little bit of Crud on bottom, which in itself is finally a relief to see as I hated vacuuming the unknown, lovely dirt roads.

Am going to add a fair chunk of water shortly so bumped up CL a bit more to allow for that.

I'm wondering if the drop in FC was so big because the AM test it is light, but the sun hasn't quite risen. Should I be setting alarm a little earlier, to test before it gets light? It'd only mean getting up about 45 minutes earlier.

 

[Summer555]

So close, 2/3!

PM
FC 32
CC 0.5

AM
FC 28.5
CC 0.5
Water clear

Bleach usage has halved over the last 24 hours.

Am keeping a record of the amount of water that goes in the pool and estimating how it'll affect CYA levels, allowing for evaporation. I feel a little geeky but it's kind of enthralling. I'm not checking this until end of the month.
So just to clarify, no matter what CYA levels will not rise ever as long as I just use bleach and if I allowed an average daily evaporation of 50 gallons then what I put in above this per day would add to the dilution? The pool cover will go back on after shocking, to reduce evaporation particularly overnight.

 

[chem geek]

So just to clarify, no matter what CYA levels will not rise ever as long as I just use bleach and if I allowed an average daily evaporation of 50 gallons then what I put in above this per day would add to the dilution? The pool cover will go back on after shocking, to reduce evaporation particularly overnight.

That is correct. The CYA will not rise unless you were to use Trichlor or Dichlor. If you use bleach (or chlorinating liquid) then you will not raise the CYA.

Evaporation concentrates what is in the water so if you then add water you just end up diluting it back to where it started. This is because only water evaporates, not CYA. To reduce CYA, one has to remove the water as with a partial drain/refill; evaporation won't work for lowering the CYA. So your use of a pool cover to reduce evaporation is fine and won't affect the CYA.

 

[Summer555]

PM
FC 34
CC 0.5

AM
FC 32
CC 0.5 (The colour is so close to being clear, just a little touch of pink)
Crystal Clear

Hopefully tonight is the end of the shock, and end of pump running 24/7! Have a 102c day coming up in 2 days so it'd be nice for the chlorine to start dropping down a little.

Will aim to keep it around 15ppm while CYA is at 150, is that a reasonable target?

What do I do with the PH at this level though, roughly where should I be reading?

 

[UnderWaterVanya]

Hopefully tonight is the end of the shock, and end of pump running 24/7! Have a 102c day coming up in 2 days so it'd be nice for the chlorine to start dropping down a little.

102 degrees Celsius is
215.6 degrees Fahrenheit

I'm hoping you meant 102 Fahrenheit - otherwise you may not want to swim in the boiling water in that pool!


- Sent using Tapatalk

 

[jblizzle]

You have discovered one of the reasons why high CYA is bad. The pooh test is not accurate if you have to maintain a FC greater than 10ppm. The test well read artificially high ... So now you will be guessing as to the true pH.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[UnderWaterVanya]

You have discovered one of the reasons why high CYA is bad. The pooh test is not accurate if you have to maintain a FC greater than 10ppm. The test well read artificially high ... So now you will be guessing as to the true pH.

Posted from my Droid with Tapatalk ... sorry if my response is short

If I recall correctly you can take the pH very quickly to help with this and also I think chem geek said high FC due to high CYA didn't make this quick read as difficult as high FC during shock process.

So until the pool owner lowers his FC he may have to read pH fast and then adjust conservatively.

Another option might be to bottle a sample and leave it in sunlight for a couple of days to allow FC to drop, but I'm unclear if the pH will hold steady.

OP Really needs to drop CYA to make this easier.


- Sent using Tapatalk

 

[jblizzle]

Leaving it in the sun will not work as the pH starts to change as soon as you take it out of the pool. That is why PH should be the first test you do.

you are correct that if you read the pH very quickly then you can get an accurate result but this is within seconds of starting the test.

Posted from my Droid with Tapatalk ... sorry if my response is short

 

[Summer555]

102 degrees Celsius is
215.6 degrees Fahrenheit

I'm hoping you meant 102 Fahrenheit - otherwise you may not want to swim in the boiling water in that pool!

Oops haha. I try and convert everything from what we use, that's quite an oversight.


Edit: Figuring out the quote thingy.

 

[Summer555]

OP Really needs to drop CYA to make this easier.

Working on this relying on splash outs & vacuuming to waste and then refilling back up, keeping evaporation to a minimum, it's a long process. Unfortunately it's possible we might be going into drought again so water is scarce and expensive, come winter time though I think the problem will resolve itself as I can do bigger drain/refills as water is not an issue then.

 

[Summer555]

So until the pool owner lowers his FC he may have to read pH fast and then adjust conservatively.

Another option might be to bottle a sample and leave it in sunlight for a couple of days to allow FC to drop, but I'm unclear if the pH will hold steady.

I was thinking that because my minimum FC target is 11, if I let it drop to 9 I could do a PH test and then bump it back up to where I need to be.


Overnight test is draggin on.
PM
FC 38.5

AM
FC 35.5
CC 0.5 (pink tinge is almost non-existant)
Water clear

I have thrown everything in the pool, brushed the walls and floor, vacuumed. Can't figure out what else the problem could be, maybe the top up I did last night may have affected it. Or maybe it's just user error at these levels.

My husband hooked the hose up to the dam tap 2 days ago to water the garden, it was flushed out with fresh water but he's contaminated it hasn't he?!

 

[UnderWaterVanya]

So until the pool owner lowers his FC he may have to read pH fast and then adjust conservatively.

Another option might be to bottle a sample and leave it in sunlight for a couple of days to allow FC to drop, but I'm unclear if the pH will hold steady.

I was thinking that because my minimum FC target is 11, if I let it drop to 9 I could do a PH test and then bump it back up to where I need to be.


Overnight test is draggin on.
PM
FC 38.5

AM
FC 35.5
CC 0.5 (pink tinge is almost non-existant)
Water clear

I have thrown everything in the pool, brushed the walls and floor, vacuumed. Can't figure out what else the problem could be, maybe the top up I did last night may have affected it. Or maybe it's just user error at these levels.

My husband hooked the hose up to the dam tap 2 days ago to water the garden, it was flushed out with fresh water but he's contaminated it hasn't he?!

Some people have seen less than exact repeatability from the FAS-DPD test - most people get pretty consistent numbers but not everyone. Make sure you are doing the tests the same way and with the same size drops etc as much as possible (ie same techniques). If you are really worried it is technique you could try this but it will use a lot of extra reagent and powder and you may hate me for it:

Do each test 3 times and average the results and then compare the OCLT based on averages.

This is not normally required but if you feel like everything is in balance and the problem is purely a testing artifact that is one way to help yourself find out.

 

[UnderWaterVanya]

102 degrees Celsius is
215.6 degrees Fahrenheit

I'm hoping you meant 102 Fahrenheit - otherwise you may not want to swim in the boiling water in that pool!

Oops haha. I try and convert everything from what we use, that's quite an oversight.

LOL - Just post in your native units and we can convert ourselves...

 

[Summer555]

Finally passed OCLT test!

PM
FC 36

AM
FC 35.5
CC 0.5 (again pink so faint it's almost negligible)

26 litres of 12.5% bleach at $29 and 5 days of patience, pre TFP I had spent well over $200 in 2 weeks and still hadn't resolved problem (in fact made it worse by blowing CYA off the chart).

Now to tackle CYA.

 

[UnderWaterVanya]

Finally passed OCLT test!

PM
FC 36

AM
FC 35.5
CC 0.5 (again pink so faint it's almost negligible)

26 litres of 12.5% bleach at $29 and 5 days of patience, pre TFP I had spent well over $200 in 2 weeks and still hadn't resolved problem (in fact made it worse by blowing CYA off the chart).

Now to tackle CYA.