Chlorine pucks - how much CYA

[Krulligo]

Hi. I still kind of new to pool ownership. We got our liner replaced on our small 15f round pool (~4700 gallons). Water is freshly refilled from tap.

Last year I had quite a bit of a problem with high CYA due to the pool store telling me to use 3" chlorine pucks. After some research, I realized that the pucks might not be such a good idea to use since it would raise my CYA levels significantly. However, I am now back to 0 CYA due to fresh refill and want to get back to that optimal 30PPM zone. I still have a bunch of pucks left over and would like to add CYA with pucks instead of buying CYA separately.

From another thread on this forum, I calculated that for my sized pool, 1 puck would up my CYA levels by about 11 PPM, so meaning that I need to use 3 pucks to reach about 30PPM of CYA. However, I just wanted to verify that I am calculating this correct. Would anyone tell me how much one standard 3" chlorine puck would raise my CYA levels in my 4700 gallon pool?

Thank you!

 

[mknauss]

Welcome to the forum!
Sure -- use Effects of Adding Chemicals in PoolMath
One 8 oz 3" puck will add 12 ppm FC and 7.1 ppm CYA to your pool.
I suggest you read through Pool School - Trouble Free Pool and even look at a few of our videos TFP-TV - Trouble Free Pool

 

[Krulligo]

Perfect thank you. So dissolving in 3-4 pucks over the next few weeks should get me to that 30-40 PPM target range. Wow no wonder I had issues with CYA in my pool last year. The pool store was telling me to use 2 pucks per week in my pool.

Thanks for the article suggestions and the videos. I have already read and watched them and wanted to switch out from advice from the pool store and go with the method outlined in the articles (mostly switch out the use of chlorine pucks to liquid chlorine - 10%). The pool store also got me to buy products like Clarifier, Algaecide, and phosphates, and told me to add them in certain amounts on a weekly bases. From my understanding I don't need these at all? So all I need to really worry about is balance my alkalinity and PH, keep adding about 400ml of liquid chlorine (10%) daily and every one or 2 weeks (depending on use) I should SLAM the pool? I am in the process of ordering a good pool testing kit (a bit harder to come by here in Canada). This sounds much simpler then the advice from the pool store.

 

[Her pool boy]

I get my testing supplies from Pool and Hot Tub Depot in London. They deliver within 2 days.

 

[PoolStored]

Welcome to TFP!

So all I need to really worry about is balance my alkalinity and PH,

Keep your pH so it starts with a 7. Simple. TA will manage itself. Only in some particular situations might we look to (typically) lower TA. Just manage pH for now.

keep adding about 400ml of liquid chlorine (10%) daily and every one or 2 weeks (depending on use) I should SLAM the pool?

Keep adding LC daily after testing FC to get FC levels back to the appropriate target range for your CYA level. FC/CYA Levels

I am in the process of ordering a good pool testing kit (a bit harder to come by here in Canada). This sounds much simpler then the advice from the pool store.

Yep, sure is. If you have a smartphone, download PoolMath, it will help you with how much of what to add!

 

[mknauss]

From my understanding I don't need these at all?

Correct.

I should SLAM the pool?

You should never have to SLAM the pool if you keep your FC at target or above based on your CYA.
Many members here have never done the SLAM process to their pool.

process of ordering a good pool testing kit

That is hard in Canada. Easiest way is to order in the USA and have delivered to a mail drop at the border. Drive over the border and pick it up.

 

[Krulligo]

Great thank you all. This is very helpful. While I'm here I had another quick "newb" question. Where do I point my return jet?

It's a 15f round pool with 1 return jet located near the top potion of the pool about 3 feet away from the skimmer. Right now I have it pointed away from the skimmer along the wall about a 45 degree angle to the bottom of the pool. Is this somewhat correct?

 

[mknauss]

You want the return jet set so it helps make a swirl pattern on the surface of the pool. This will bring the material that falls on the surface of the pool to the skimmer. Be sure you do not try to fight the wind direction.

 

[Krulligo]

OK. So I have a couple more questions. I am still waiting on a testing kit so I decided to get my pool water tested at the store. Here are my values (mind you this is a completely fresh refill, water temperature still quite cold at 57F):

Total Alkalinity = 110 ppm
pH = 7.5

These look good and looks like I don't need to adjust anything here.

Free Chlorine = 0 ppm
Stabilizer = 0 ppm

These are as expected due to a fresh refill. I am addressing these by getting my stabilizer up to 30-40 ppm, and also adding liquid chlorine.

Calcium Hardness = 120 ppm --> The store suggested a level between 200-300 ppm and wanted me to buy 3 kg of calcium to add to my pool. They say that this will prevent corrosion of pool surface and equipment. However, from reading the articles here, I am under the impression that since I have a vinyl pool, that I don't need to worry about calcium (unless it is very high). Am I correct here?

Borate = 0 ppm - The store suggested levels between 40-60 ppm to make water feel softer and wanted me to buy a product called SkinSilk. Do I need to worry about this? Does it make a huge difference if I kept it at 0 ppm?

 

[Oly]

Welcome,
Be very careful relying on pool store test results. Realize adding anything based on that data is suspect.
Yes there should be no CYA and very low if any FC in your fresh fill so get those going and stay in the zone FC/CYA Levels.
No need to adjust CH now wait for your test kit and check it again but you are vinyl.
I don't use Borate. I may benefit slightly with my SWCG but the risk to my grand-kids, animals and my yard dissuaded me and all is well. Less is more.
Enjoy your pool and post up the results from your home testing. Do you have a FC/pH tester at home?

 

[Krulligo]

Unfortunately good testing kits are hard to get here in Canada so I am trying to source one from somewhere. Right now, the pool store results are all I can go by. I do not have a FC tester other then some strips, but I do have access to a pH meter (scientific laboratory grade) at work that I am going to test my water with tomorrow to confirm the pool store's results.

"No need to adjust CH now wait for your test kit and check it again but you are vinyl." So a bit confused, do I still need to worry about CH if I am vinyl or should I just leave it as is? I will stay away from borates for now.

 

[Oly]

Is your water from a municipal system, a well or delivered by tanker truck?
Vinyl can be affected by high Calcium Hardness and develop scale. Low CH, aggressive water, is less a problem for vinyl pools than fiberglass or plaster pools
A good test kit allows you to balance your pool water properly at home and repeatably when needed, try to source a good test kit, Test Kits Compared as its the foundation of managing water chemistry. Lots of sad stories in here of folks relying too much on pool store testing.
Someone once said....."It's not what you don't know that will get you in trouble, it's what you think you know that ain't so".
You are smart to test for accurate pH as your pump equipment can be damaged when out of range.

 

[Mdragger88]

Here’s some info on ways to obtain a proper kit - section 5

Pool Test Kits - Further Reading

www.troublefreepool.com

 

[Krulligo]

Thanks for the reply. The water was from a municipal system. Completely understand how valuable a good at-home test kit is. I wanted to call around some local pool depot stores tomorrow to see if anyone carries the Taylor kits.

On a side note, I wanted to add my stabilizer first and get it up to 40 ppm (4700 gallon pool). I used the pool math calculator and it is telling me going from 0 to 40 ppm, I need to add 25 oz (700 grams) of stabilizer. I was wondering if this is correct. Also, I put this in a sock and leave it in the skimmer basket with pool pump running 24hrs for couple days (until it all dissolves) correct?

Thank you for all the help.

 

[Oly]

Yes then safe to assume your CYA is 0 and use PoolMath always double check, but for your pool size (assuming gallons?) you will need 25oz or 712grams of 100% granular CYA or just under 6 trichlor tabs 8oz. Work your way up and test is best practice to avoid over shooting. Avoid using the skimmer, rather hang a old tied off sock in the pool in from of a return, well away from the wall and squeeze the sock after the granules have turned to mush. CYA will discolor your vinyl if it is in contact for very long before going into solution so avoid that. Also trichlor tabs will do the same.

 

[PoolStored]

I wanted to call around some local pool depot stores tomorrow to see if anyone carries the Taylor kits.

If you do, ask specifically for the K-2006 or the K2006C. The C just means larger reagent sizes. If they don't have either of these, don't buy it. Anything else (other than the TFTest kits) will not have the tests you need, specifically the FAS-DPD for FC.

 

[Krulligo]

Another question regarding CYA. Would it be easier to pre-dissolve 700g of CYA granulated in let's say 1 liter of water. Would it go into solution in a few hours of constant stirring and some heat added? Then once dissolved just dump the solution into the pool while pool pump running to spread it around.

Also, with my Alkalinity at 110-120 and pH of 7.5, will I expect a significant drop in pH from adding CYA or is the alkalinity going to buffer it?

 

[Oly]

I would not use one liter to disolve 700g. Better to use 4 gallons in a bucket but still use the sock and squeeze, my opinion. To get all the granules to fully disolve takes some time and you will want to be done. The sock filters undissolved granules and protects your liner, your choice.
You will get a slight lowering of pH from the CYA, use pool math in "effects of adding chemicals" to estimate. Yes your higher level TA will drive your pH back up in no time with a little water movement and aeration.

 

[IceShadow]

I've tried pre-dissolving CYA in a bucket. It doesn't really want to do it.