Can I treat mustard algae with CYA at 120 without lightening liner?

[DistantHorizon]

The title says it all. Neglected the pool while not swimming in it this summer, and ran trichlor FAR after I should've stopped. (Pool has a slow intermittent leak; CYA drops over winter as water leaks and is refilled; during season I run mostly trichlor until CYA is around 80; repeat) I also let chlorine levels drop too low on multiple occasions, and ended up with some persistent algae that seems to come back in the same spots a few days after SLAM - I'm thinking mustard? First year I've ever neglected pool, and as a result, first year I've ever had trouble with algae that didn't clear overnight with a SLAM.

Selling my house but I have a conscience, and I'd like to not leave the new owners with mustard for next year... but I don't want to get rid of it at the expense of the pool liner. Thoughts?

 

[Texas Splash]

Whether or not it's MA, the initial treatment is still the same - SLAM via Pool School - SLAM - Shock Level And Maintain. Once you pass all 3 SLAM criteria, only then for the next 24 hours do you raise the FC to SLAM level as indicated on the Poolmath calculator . But first - SLAM.

 

[chiefwej]

Since the 120 is beyond the limit of the test it could be much higher. Are you sure tha CYA is 120? Did you do a 50/50 pool/tap water test to confirm?

 

[DistantHorizon]

Whether or not it's MA, the initial treatment is still the same - SLAM via Pool School - SLAM - Shock Level And Maintain. Once you pass all 3 SLAM criteria, only then for the next 24 hours do you raise the FC to SLAM level as indicated on the Poolmath calculator . But first - SLAM.

Sure, I know how to SLAM, and have done that. But can I run shock up to 64 like Pool Calculator suggests to treat for mustard WITHOUT lightening the liner?

Since the 120 is beyond the limit of the test it could be much higher. Are you sure tha CYA is 120? Did you do a 50/50 pool/tap water test to confirm?

Good call, I did not. I cheated on this one, doing math based on how much trichlor had been added since last CYA test, and with estimated water loss due to backwash. Likely I could be off by 5 or 10 or more.

Have to go out of town for a couple of days, so I can't do more yet - but I'll post an accurate CYA before I proceed further. Thanks for the help both of you!!!

 

[duraleigh]

But can I run shock up to 64 like Pool Calculator suggests to treat for mustard WITHOUT lightening the liner?

The theoretical answer is absolutely yes and the practical answer is I would do it in my pool but start to get cold feet suggesting dosages when you are so far out of normal ranges.

If you absolutely, positively cannot drain 50% of your pool to get the CYA down, then, yes, I would personally SLAM at that value and cross my fingers just a tiny bit.

 

[DistantHorizon]

Since the 120 is beyond the limit of the test it could be much higher. Are you sure tha CYA is 120? Did you do a 50/50 pool/tap water test to confirm?

Checked via dilution method, indeed, it is 120.

The theoretical answer is absolutely yes and the practical answer is I would do it in my pool but start to get cold feet suggesting dosages when you are so far out of normal ranges.

If you absolutely, positively cannot drain 50% of your pool to get the CYA down, then, yes, I would personally SLAM at that value and cross my fingers just a tiny bit.

I can drain; I hate to put a big water bill on my records for potential house buyers (increase potential pool-owner fears); I don't like the expense; and hate to waste the water from an environmental standpoint. But you make a good point and I will have to consider it.

 

[JoyfulNoise]

Checked via dilution method, indeed, it is 120.



I can drain; I hate to put a big water bill on my records for potential house buyers (increase potential pool-owner fears); I don't like the expense; and hate to waste the water from an environmental standpoint. But you make a good point and I will have to consider it.

Don't know where you live but can you use your pool water for irrigation purposes? CYA has no effect on plants (heck, it probably helps when soil bacteria break it down to ammonia and nitrates) and chlorine dissipates fairly quickly in soil. Some grasses are susceptible to chlorine but you could always test a small patch to see how it reacts.

Just a thought....


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[DistantHorizon]

Don't know where you live but can you use your pool water for irrigation purposes? CYA has no effect on plants (heck, it probably helps when soil bacteria break it down to ammonia and nitrates) and chlorine dissipates fairly quickly in soil. Some grasses are susceptible to chlorine but you could always test a small patch to see how it reacts.

Just a thought....


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That's not a bad idea, but it would still going to jack my water bill up significantly, and the part of yard that needs it isn't very close to the pump station or backwash hose. Rigging extra hose would be a great option if I was sticking around, but I'm doing a quick unexpected move where I'm already up to my eyeballs in projects.

 

[JoyfulNoise]

That's not a bad idea, but it would still going to jack my water bill up significantly, and the part of yard that needs it isn't very close to the pump station or backwash hose. Rigging extra hose would be a great option if I was sticking around, but I'm doing a quick unexpected move where I'm already up to my eyeballs in projects.

Agreed. Pool/Irrigation water exchange is a long term thing. Several TFPers have used it as a means of reducing calcium hardness by turning off their landscape irrigation and using the pool to water the yard. By doing that, the water you'd normally use for irrigation goes in as fill water to the pool and slowly lowers the "permanent" compounds in the water (CYA, salt, borates, phosphates, calcium, etc). Assuming, of course, your water supply is decent (no metals, low CH, etc).


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[chiefwej]

I can understand that you aren't looking to create a record of extremely high utility bills on a property you are trying to sell. Do you have an alternate way of replacing water? Do you have a good neighbor with a couple long garden hoses that you can compensate, or is water delivery available where you are at?

Are you really helping out the next owner, if he has a pool full of water with an extremely high CYA level? Even if it's clear when he takes over it won't be easy to manage.

 

[DistantHorizon]

I can understand that you aren't looking to create a record of extremely high utility bills on a property you are trying to sell. Do you have an alternate way of replacing water? Do you have a good neighbor with a couple long garden hoses that you can compensate, or is water delivery available where you are at?

Are you really helping out the next owner, if he has a pool full of water with an extremely high CYA level? Even if it's clear when he takes over it won't be easy to manage.

This pool seems to run best with CYA in the 70-90 range (no shade whatsoever), and thanks to a slow intermittent leak, every winter over half of the water gets replaced... so I'm not saddling the next owner with a high CYA at all. I might have a neighbor to ask, that's a thought!

 

[Tepelus]

If you do not want to drain 50% of water now you can add 7 oz of sodium bromide or 10 tablets of bromine. That will make your pool a bromine pool for a while. CYA will be not relevant this year. Just add bleach and keep pH in range. In spring you will treat your pool as you would normally would.