High cya, help!

[Poolnurse]

Hi! I bought a house with a pool this spring and thought everything was going well until our cya levels rapidly escalated over the last couple weeks. (The feeder was going through trichlor tabs so fast, it was keeping the FC level between 7-11ppm even when I tried turning it all the way down). A few days ago I stopped using the feeder (started using skimmers) and today I bought non-stabilized chlorine tabs (sodium hypochlorite) and don't ever plan to use trichlor again.
Today's test:

FC 3
CC 0
pH 7.6
TA 100
CH 180
CYA >100 (the dot disappeared about halfway to 100)

The water looks clear but I have some yellow/green algae that keeps trying to grow along the southern wall and steps (I have been brushing/vacuuming it off for the last couple weeks but it keeps coming back).

My husband wants to go with the pool store recommendation of adding a copper algaecide (they told him not to shock). I want to try shocking/slamming but don't know how high to go since I don't have an accurate CYA value and I read that I need to get the CYA down before slamming anyway.

I drained and refilled about 3 inches today but I feel bad doing this on our well and with our CYA so high I feel like it won't make a difference anytime soon. The pool store said to give it a few months and never drain more that a foot to preserve the plaster... Is it really safe to drain half the pool or should I try draining and filling simultaneously to swap out the water?

What do I do in the meantime while I try to get there CYA down? Can I shock and how do I know how high I need to get the FC?

Thank you!

 

[YippeeSkippy]

Hey there PoolNurse, welcome to TFP .

When you test for CYA and it says "100", it very well could be much more. THe test tops out at 100. So you need to do a diluted test-
Mix equal parts of pool water and tap water and mix well. Then repeat the test using this mixture as your sample, and double the results.

This will tell us how much you need to drain and refill to lower the CYA. Nothing else will do it, no matter what a pool store tries to sell you.

Putting copper containing *anything* into a pool is a disaster waiting to appear!! Copper is what causes stains on the pool surface and your blond hair swimmers to suddenly develop green tinted hair.

Your FC is far too low, which is why you have algae. See this -->FC/CYA Levels

You might investigate the cost of trucking in fresh water if your well can't fill the pool. If you decide to do the SLAM process as it is *now* its gonna take a whole mess more liquid chlorine.

Go ahead and use CalHypo as needed because for a plaster pool your CH is too low also. But don't use it after your CH gets to be 250-300.

Maddie <--another nurse

 

[YippeeSkippy]

 

[duraleigh]

Welcome to the forum

Your first step is for you and your husband to get on the same page. What we teach at TFP and what the pool store will tell you will not match up.....period.

If you decide on the advice here at TFP, you really should stay out of the pool store. The next step would be to follow the instructions Maddie gave you above for doing the dilution method for your CYA test and then reduce your CYA down to around 50 ppm.

With CYA currently at 100+, your water is pretty unmanageable and your chlorine costs will be through the roof. This late in the swim season, you may decide to limp along as best you can and start over in the Spring but it will be difficult for you to get your pool algae free with your CYA where it is.

 

[ajw22]

Welcome to TFP.

@mknauss can give you a water exchange method so that you do not have to worry about exposing your plaster during a drain.

 

[Poolnurse]

Thank you guys! I just checked CYA with the 1:1 dilution method and it is probably just over 200. I also noticed that the Taylor kit (it came with the house) reagent expired in April so I ordered another one. In the meantime should I still trust the numbers?

I got my husband on board with me...we're planning to try the water exchanging method and if that doesn't seem to work we'll call around and order fresh water.

We're also going to dump 5 gallons of bleach in today to get up to the minimum FC, start using the nsc tabs, and add some calcium. I'll start checking the levels daily to maintain the FC with nsc/liquid bleach and hope to get the CYA low enough to slam in the near future. Does that sound the the right way to handle this?

 

[ajw22]

CYA reagent is very stable and good for more then a year. Your CYA test is valid.

 

[mknauss]

You can exchange some water without draining.

If you place a low volume sub pump in the deep end and pull water from there while adding water in the shallow end (through a skimmer or into a bucket on a step so you lessen the water disturbance) you can do a fairly efficient exchange. That is assuming the water you are filling with is the same temperature or warmer than your pool water. If your fill water is much cooler than your pool water, then switch it. Add the water to the deep end (hose on bottom) and pull water from the top step.

The location of the pump and fill hose may change if you have salt water, high calcium, etc.
In my pool, with saltwater and high calcium when I drain, I put the pump in the deep end and hose in shallow end. The water in the pool weighs more per unit volume than the fill water from the hose.

Be sure to balance the water out and water in so the pool level stays the same. Also be sure your pool pump is disabled during this process. Once started do not stop until you have exchanged the amount of water you wish.

 

[holdup1time]

Hi! I bought a house with a pool this spring and thought everything was going well until our cya levels rapidly escalated over the last couple weeks. (The feeder was going through trichlor tabs so fast, it was keeping the FC level between 7-11ppm even when I tried turning it all the way down). A few days ago I stopped using the feeder (started using skimmers) and today I bought non-stabilized chlorine tabs (sodium hypochlorite) and don't ever plan to use trichlor again.
Today's test:

FC 3
CC 0
pH 7.6
TA 100
CH 180
CYA >100 (the dot disappeared about halfway to 100)

The water looks clear but I have some yellow/green algae that keeps trying to grow along the southern wall and steps (I have been brushing/vacuuming it off for the last couple weeks but it keeps coming back).

My husband wants to go with the pool store recommendation of adding a copper algaecide (they told him not to shock). I want to try shocking/slamming but don't know how high to go since I don't have an accurate CYA value and I read that I need to get the CYA down before slamming anyway.

I drained and refilled about 3 inches today but I feel bad doing this on our well and with our CYA so high I feel like it won't make a difference anytime soon. The pool store said to give it a few months and never drain more that a foot to preserve the plaster... Is it really safe to drain half the pool or should I try draining and filling simultaneously to swap out the water?

What do I do in the meantime while I try to get there CYA down? Can I shock and how do I know how high I need to get the FC?

Thank you!

Curious where you found non stabilized chlorine tablets....that would be perfect...I'm running through liq chlorine like crazy trying to keep up my FC ....my cya is 80....made the switch too late..

 

[Poolnurse]

Curious where you found non stabilized chlorine tablets....that would be perfect...I'm running through liq chlorine like crazy trying to keep up my FC ....my cya is 80....made the switch too late..

Or local pool store has them... Maybe pool stores are good for something after all ?

 

[duraleigh]

Careful with the "non-stabilized" tablets. I assume they are Calcium Hypochlorite and not intended for a tri-chlor puck feeder. Do you have a brand name for these tablets?

 

[Poolnurse]

Careful with the "non-stabilized" tablets. I assume they are Calcium Hypochlorite and not intended for a tri-chlor puck feeder. Do you have a brand name for these tablets?

Thank you, they are actually pool life brand calcium hypochlorite and we are putting them in the skimmers along with dumping household bleach directly into the pool to keep the FC around 7.5% of the CYA level.

 

[duraleigh]

Yeah, I have seen the Cal-hypo pool life pucks around. A new product that seems to show promise. I am not a huge fan of putting tabs in the skimmer but I think that is a MUCH lesser evil than tri-chlor tabs and the subsequent over-stabilization of your pool water.

It will be interesting to watch how these pool life cal-hypo tabs turn out. If they don't have any GIANT bugaboos, it will be a real winner of a product. Of course, they leave a calcium residual in your pool water which I think eliminates them from the Southwest hard water areas but for Florida and the Northeast, they have potential.

 

[frogabog]

I'm interested in these, but I don't need a whole bucket! I found it on Amazon for $104. Another brand is $180 though so the Pool Life brand seems a decent deal.

There is next to 0 CH in our city water. Even the people on wells in the PNW don't have very high CH. A little extra might not be the worst and I could go out on my boat for a few days and not worry about CYA rising.