cya too high

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M

mlkh

0
Jul 5, 2008
3
Burleson, TX
I am new to the BBB method but can not seem to get my FC high enough to keep algae down. My CYA is 100 and I flocked about a week ago and vacuumed to waste approx. 6in down then did a refill. It did not lower the CYA. I continue to pour bleach in at high levels but it is not helping. I am spending $30/week on bleach so I am looking for some help. Is draining half my pool the only answer...I have an inground liner pool with 36,000 gals. That is a lot of water! Thanks for your help!
Martha
 
Welcome to TFP!

Unfortunately, the only way to lower the CYA is by draining and refilling. You will need to replace 50% of your water, however, do not do it all at one time. You run the risk of floating the pool and/or getting wrinkles in you liner. Continue to do partial drains and refills until you get the level down to at least 50.

Do you have a testing kit that has the FAS/DPD CL test and a CYA test? If not, you need to get one. I suggest a TF Test Kit sold at tftestkits.com or a Taylor K-2006. If your CYA is really 100, your target level for CL is 14. There are no other tests that will be able to test for that high a CL level. To reach that target for a 36,000 pool, you would need to use about 8 gallons of 6% bleach if you started with a FC reading of 0.

Do you know what your CL is now?
 
Frequently when your CYA test comes out at 100 the actual results are much higher. That would explain why when you replaced some water your CYA didn't change. I concur with the prior advice; partial drains and refills to lower to the 50ish range, don't do it all at once.
 
Thanks so much for your reply, Yes I have access to the TF 100 Kit and have been going by it. Do I need to rent a pump and drain half the pool or just do it by the pump on waste? That will only take it down below skimmers which is about 4 in. If I do it by the pump, do you have any suggestions to try to keep the water decent. Today my FC and TC are at 3.5, the water is cloudy and has a light green tinge in the deep end. The water temp today was 86, the air temp was 100. Thanks for your help, I am trying to be patient but it is hard when the pool water will not stay nice and clear. That is why I flocked it so I could get it clear for a party, only to keep it clear for about a week then right back to where I had started!
Martha
 
Personally to avoid other troubles I would just do it by the pump below the skimmer, once or twice more, and that should get it to a more managable number. I'd do it twice and retest the CYA after the second drain/refill. Test the FC in between and make sure you have enough FC in there, after the 2nd drain test your CYA again. Then adjust your targets according to your cya level.
 
You can rent a pump, but do not drain half of the pool at one time. Try doing 25% and then testing your CYA.

FPM is right. Your CYA is probably over 100. For a CYA of 100, you need to add 6 1/8 gallons of 6% bleach to get up to FC 14. How much bleach have you been adding daily?
 
Last night I added 3 gallons and this afternoon I added 3 gallons. I have not tested after todays add but this am my FC and TC were 3.5. Tomorrow I will do a partial drain and refill, then do it again. I will get back with you with new #'s after I do that.
Martha
 
We all agree that a too high CYA level is undesirable and we know that the only way to reduce it is through dilution. In Martha's case that will be at least eighteen-thousand gallons. That's a huge amount of water!

The fresh water has to come from somewhere: a reservoir, an aquifer, piped in from another state. The waste water goes into the sewers, septic system, or is drained on the land where it will likely evaporate or run off (the location is TX) when discharged rapidly rather than slowly soak into the ground to replenish the aquifer. At a time where droughts have been and are threatening our food supplies we pool owners need to be especially aware of and responsible about our water usage.

High CYA levels require special water management and diligence. Just as the stabilizer didn't get that high in one week it doesn't really need to be brought within a more normal range in that short of a time. This pool could be drained of 1,000 gallons per week over the next several months. With a little bit of plumbing magic the drain hose could be made to connect to a soaker hose and provide irrigation for the surrounding landscaping. Refilling of 1,000 gallons of fresh water would put far less stress on the water supply.

I often feel that we pool owners are an especially privileged group for being able to create and live in an environment where we have the luxury of playing in a dwindling natural resource. I believe that we need to hold ourselves to a higher standard of environmental stewardship because of that.
 
Hi Martha,

Adding information about your pool and equipment in your signature will be a big help. All the information needed is listed in Pool School's first article...."Getting Help....Read this before you post" There is a link to Pool School at the top of each page in the sub-heading and a link in my signature.

Once you determine the info needed, go to "User Control Panel" (upper left, under TFP logo) and select "Profile" and then "edit signature".

Since your main problem seems to be the high CYA, partial drains are recommended; however, you may not need to lower your CYA to the 'recommended levels'. SOME pools, depending on location & exposure to sunlight, etc., do quite well with a slightly higher CYA, such as 70 to 80.

Hopefully, members from your part of the country will chime in and give their view on the CYA levels that work for them. Not having to drain as much water would definitely be a very good thing.

Keep us posted on your progress and welcome to the forum. :-D
 
AnnaK said:
We all agree that a too high CYA level is undesirable and we know that the only way to reduce it is through dilution. In Martha's case that will be at least eighteen-thousand gallons. That's a huge amount of water!

The fresh water has to come from somewhere: a reservoir, an aquifer, piped in from another state. The waste water goes into the sewers, septic system, or is drained on the land where it will likely evaporate or run off (the location is TX) when discharged rapidly rather than slowly soak into the ground to replenish the aquifer. At a time where droughts have been and are threatening our food supplies we pool owners need to be especially aware of and responsible about our water usage.

High CYA levels require special water management and diligence. Just as the stabilizer didn't get that high in one week it doesn't really need to be brought within a more normal range in that short of a time. This pool could be drained of 1,000 gallons per week over the next several months. With a little bit of plumbing magic the drain hose could be made to connect to a soaker hose and provide irrigation for the surrounding landscaping. Refilling of 1,000 gallons of fresh water would put far less stress on the water supply.

I often feel that we pool owners are an especially privileged group for being able to create and live in an environment where we have the luxury of playing in a dwindling natural resource. I believe that we need to hold ourselves to a higher standard of environmental stewardship because of that.
Click to expand...

Excellent post, AnnaK. Thank you.
 

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Martha,

Depending on the source of the chlorine demand, there are other options available when one has a high CYA level, but they usually cost more money. If the chlorine demand is due to nascent algae growth, then use of a supplemental algaecide such as a weekly dose of PolyQuat 60 or use of a phosphate remover, will reduce or eliminate such growth (the phosphate remover may be more expensive, depending on phosphate levels, but it will eliminate algae growth if you get phosphates below 150 ppb). This could reduce the amount of chlorine that is needed, but as I said, at a cost. A weekly maintenance dose of PolyQuat 60 would cost you about $5.60 (initial dose is three times that amount). For the phosphate remover for your pool size it would take 19 fluid ounces of Natural Chemistry PhosFree for every 100 ppb of phosphates and this costs about $6 so can get expensive if phosphate levels are high (1000 ppb would cost $60) though would only cost this much in a one-time dose with weekly maintenance much lower (probably around $6 so the same as PolyQuat 60 but more effective at stopping algae growth).

This might not be a bad option while one slowly dilutes the water over time. When the CYA gets lower, then you can just maintain an adequate chlorine level and discontinue use of the algaecide or phosphate remover. You would still have chlorine loss from sunlight and from bather load, but this should be lower than what you are currently seeing. If you were able to get to a chlorine demand of 2 ppm FC per day or less, then that would be 1.6 96-ounce jugs of bleach or around $2 per day or $14 per week depending on bleach prices -- about half of what you are spending now.

The above is not the conventional advice on this forum since managing a pool with chlorine alone is almost always possible, but there are always tradeoffs and having a high CYA level in a larger pool does mean a lot of water replacement and using lots of chlorine if algae is developing and even more chlorine to shock the pool to get ahead of such growth.

Richard
 
Excellent points, Anna!

Martha, I agree, it's not critical to lower down to "recommended levels" asap, every pool IS different. I ran all summer last year with a CYA of 70, and managed fine. I used more chlorine, but I did alright.

So use your judgement, for your location, your pool, etc. Good luck, we're here to help.... :)
 
I agree with the others who say not to drain it all at once. Keep your chlorine levels up & drain slowly. Vacuum to waste, let rain water dilute, etc. Even though your chlorine levels have to be higher, the CYA does keep the chlorine from burning off quite so fast, so that helps with the chlorine usage. Your algae is part of what's using your chlorine right now.

If you do decide to use an algaecide, make sure it's a polyquat 60, not a copper based.
 
I for one survived a CYA of 100 for a summer. Upon opening the next year, it was way down. Not sure of the exact figure.

If you have an CYA of 100, a FC of 3.5 just isn't going to cut it. You have to keep it up nearer to 8 or 10ppm. Get used to the idea of buying bleach all week long. You also have to have excellent circulation for the chlorine to get all the nooks and crannies. So, operate your pump/filtration system a MINIMUM of 12 hr. day for a pool you size. I would keep mine operating 24/7 when pool temps were >86 degrees.

I did use polyquat weekly at the higher maintenance dose when my CYA was high. Not so much anymore now that its around 60ppm.

Living in drought conditions here in North Carolina makes me reconsider draining and refilling. Use your best judgement.
 
Preventing the situation is ideal, but better to solve the problem quickly than drag it out, imo. I don't disagree that we need to be responsible pool owner, but ecologically speaking who's to say what's better, draining water or continuing to use much higher amounts of chlorine? What are the costs to the environment of the production of that chlorine? How much energy is used in the process, how much waste is created? How much fuel and emissions from the transport? Are the empty containers being recycled and at what cost? I don't claim to know, but saying not to drain the pool to conserve water may be counter productive both to solving the problem and in terms of total environmental impact. Just a thought.
 
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