Need help getting pool in shape so I can close it....

(30000 Gallon, 20x40, Vinyl IG pool.... Just moved into this house on 7/1 and this is my first pool.)

We are in the process of remodeling around the pool and renovating the landscaping so my pool kind of got out of hand. By out of hand, I mean the bottom and sides were covered with a greenish-yellowish slime, at least it was as far as I could tell... I couldn't see the bottom in the deep end.

For 3 days or so, I dumped 10 gallons of bleach in the pool. I also put 6 3" tablets of chlorine in the chlorinator and turn it all the way up. I can see the bottom of the pool now, but it doesn't look like all the algae is dead.

At this point, I am just trying to get my pool back "in shape" so that I can close it down. I just tested the water and here are my numbers:

FC 2
TC 3
Ph 7.0
TA 100-110
CYA 65

I am sort of stalled here... What do I do now.... Get my pH up? If my limited knowledge is correct, don't I need to raise my pH up before anything? Then adjust my TA, then chlorine?

Is there, somewhere on this forum, a step-by-step guide on what to do, the order in which to do it, and how to do it (i.e. add X pounds of baking soda to raise TA by Y amounts etc. )?

Thanks,
Ed

Welcome to the pool forum!

You can use Borax to raise your pH. It will take about 250 ounces of Borax (about 3.3 boxes that are 76 ounces each) to raise the pH from 7.0 to 7.5, but you could just raise your pH to around 7.3 instead (using 167 ounces of Borax or about 2.2 boxes) since your liqud chlorine and high FC will raise the pH -- eventually when you are done battling the algae and the FC gets lowered the pH will drop as well back to your 7.3 (or thereabouts).

After adjusting the pH (to prevent your vinyl from getting hurt by the acidity), the top priority for you is to get rid of the algae and that means keeping your FC level up at shock level according to Ben's Best Guess CYA chart which means adding liquid chlorine or bleach to maintain an FC of 20. Do you have a FAS-DPD chlorine test kit so you can test such high chlorine levels? By maintaining this high FC, all of the algae will get killed. You need this high FC because your CYA is a bit on the high side at 65. It may take more than just the 3 days to kill all the algae. Also, you will need to vacuum up the dead algae and/or clean your pool filter which hopefully has been filtering it out.

Your use of 3" tablets in the chlorinator means you are using Tri-Chlor tablets and these not only add chlorine, but also add CYA to your pool so you should stop using them because you already have high CYA. Also, the Tri-Chlor tablets are very acidic which is why your pH got low. Just use liquid chlorine (chlorinating liquid from the pool store or unscented bleach from anywhere, whichever is cheaper "per % of chlorine"). You can use BleachCalc to calculate how much chlorine to add or just remember the rough rule that 1 gallon of liquid chlorine will add the "% of chlorine" amount of ppm in a 10,000 gallon pool. So one gallon of 6% bleach adds 6 ppm in a 10,000 gallon pool (and 2 ppm in a 30,000 gallon pool, etc.).

That's all you should worry about right now. Your TA is OK. Remember that the most important rule when battling algae is Patience, Patience, Patience. I'm fairly certain that your pool will be completely clear within a week or less. You'll know all the algae is dead when you don't see any more, the pool is clear, and the FC level doesn't drop overnight (it may drop in the day if the pool is exposed to sun).

[EDIT] If you have a PC, you can use Michael Smith's BleachCalc which you can get from this link. It won't calculate the amount of Borax to adjust pH, but it will give do most everything else. [END-EDIT]

Richard

Thanks for the info.... Added the Borax.... Waited a couple of hours, then added 10 Gallons of 6% bleach, which If my calculations are right, should bring my FC up to a little over 20 PPM. 10 Gallons of 6% increases 30Kgallons by 2 ppm, so that would increase it by 20 PPM right? Will I need to add this much chlorine each day? Or will the FC level fall slow enough so that I can add just enough to maintain the FC > 20.

WHat is the way to calculate amount of Borax to add? How many pounds per what?

Honestly, I don't know if I have a FAS-DPD or whatever it was. I bought my kit at The Pool Place, so I'll check it and see.

Also, I turned the Chlorinator to OFF.

As an added "bonus", I found a ex-chipmunk in my skimmer while working on the pool. Is there anyway to prevent the little guys from getting in the pool? This was the second one, since we moved in but we were able to help the first one out before he met his demise.


Ed

Quote:

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Originally Posted by chem geek

Welcome to the pool forum!

You can use Borax to raise your pH. It will take about 250 ounces of Borax (about 3.3 boxes that are 76 ounces each) to raise the pH from 7.0 to 7.5, but you could just raise your pH to around 7.3 instead (using 167 ounces of Borax or about 2.2 boxes) since your liqud chlorine and high FC will raise the pH -- eventually when you are done battling the algae and the FC gets lowered the pH will drop as well back to your 7.3 (or thereabouts).

After adjusting the pH (to prevent your vinyl from getting hurt by the acidity), the top priority for you is to get rid of the algae and that means keeping your FC level up at shock level according to Ben's Best Guess CYA chart which means adding liquid chlorine or bleach to maintain an FC of 20. Do you have a FAS-DPD chlorine test kit so you can test such high chlorine levels? By maintaining this high FC, all of the algae will get killed. You need this high FC because your CYA is a bit on the high side at 65. It may take more than just the 3 days to kill all the algae. Also, you will need to vacuum up the dead algae and/or clean your pool filter which hopefully has been filtering it out.

Your use of 3" tablets in the chlorinator means you are using Tri-Chlor tablets and these not only add chlorine, but also add CYA to your pool so you should stop using them because you already have high CYA. Also, the Tri-Chlor tablets are very acidic which is why your pH got low. Just use liquid chlorine (chlorinating liquid from the pool store or unscented bleach from anywhere, whichever is cheaper "per % of chlorine"). You can use BleachCalc to calculate how much chlorine to add or just remember the rough rule that 1 gallon of liquid chlorine will add the "% of chlorine" amount of ppm in a 10,000 gallon pool. So one gallon of 6% bleach adds 6 ppm in a 10,000 gallon pool (and 2 ppm in a 30,000 gallon pool, etc.).

That's all you should worry about right now. Your TA is OK. Remember that the most important rule when battling algae is Patience, Patience, Patience. I'm fairly certain that your pool will be completely clear within a week or less. You'll know all the algae is dead when you don't see any more, the pool is clear, and the FC level doesn't drop overnight (it may drop in the day if the pool is exposed to sun).

[EDIT] If you have a PC, you can use Michael Smith's BleachCalc which you can get from this link. It won't calculate the amount of Borax to adjust pH, but it will give do most everything else. [END-EDIT]

Richard

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Yes, your 10 gallons of 6% bleach should increase your chlorine by 20 ppm in your 30,000 gallon pool. If your pool is exposed to sunlight in the day, then you could lose up to half the chlorine during the day, though this time of year I would suppose that you might only lose about one-third (or if the day is overcast you might not lose much at all). I doubt that you will need to add 10 gallons each day -- I would guess 3-5 gallons or so depending on how much algae you still have. You will lose more than that if you still have algae that is getting killed and oxidized. Just try and keep the chlorine level up and check it as often as you can, especially during the day (if possible -- at least morning and night). Because you have a vinyl pool, you can't just throw in extra chlorine to be too high in the morning because you could risk fading your liner, but try and keep the FC close to 20 as much as you can.

The amount of pH rise that Borax causes is dependent on the starting pH and the TA level (and CYA level). 10 pounds of Borax in your 30,000 gallon pool will raise the pH from 7.0 to 7.29, but if you start with a pH of 7.5 it will raise the pH to 8.14 so you can see how the starting pH makes a big difference as to the effect of the Borax (this same effect happens with other choices of base such as Soda Ash or Caustic Soda as well). When adding acid or base, it is usually a good idea to add about half of what you might expect you need and then measure to see what really happened. Sorry that it's not simpler than that. The "guidelines" that come on bottles of pool products of acid or base are just applicable near a typical pH not far from 7.5 and with a TA in the normal 80-120 range.

If your pool chlorine test kit has you look at the color of the liquid compared to a standard, then if this color is shades of yellow then this is an OTO test kit; if it's shades of magenta then this is a DPD test; if instead of looking at the color you add drops until a magenta color disappears and count the drops, then this is a FAS-DPD test. The OTO is least accurate, but can measure high chlorine levels, the DPD test is more accurate, but can't measure chlorine above around 10 ppm, and the FAS-DPD is the best since it is the most accurate and can measure high chlorine levels (up to 50 ppm). If you don't have a FAS-DPD test, you can measure the higher levels of chlorine by diluting it with distilled water, but this isn't terribly accurate (but is better than not measuring it at all) -- so diluting by mixing 1 part pool water with 4 parts water is 5:1 dilution so if you measure 4 ppm then that's 4*5=20 ppm in your pool.

Gee, I have no idea how to keep the chipmunks away. Didn't know the critters longed to be swimmers.:) Perhaps someone else has a suggestion for that one.

Richard

CelticDaddio...do a web search for Skamper Ramp and you'll see a device that should help keep your chipmunks from an early demise. It also comes in a "Big Dog" variety for animals up to 90# but hopefully, your chipmunks aren't THAT big!!:eek: :D :D

I forgot to ask this, but I assume I should be running the filter the entire time I have the FC up to kill the algae....Is that right?

Ed

So... if I know the starting pH (and TA and CYA), what is the formula for calculating the target pH given a particular amount of Borax?

Quote:

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Originally Posted by chem geek

The amount of pH rise that Borax causes is dependent on the starting pH and the TA level (and CYA level). 10 pounds of Borax in your 30,000 gallon pool will raise the pH from 7.0 to 7.29, but if you start with a pH of 7.5 it will raise the pH to 8.14

Richard

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Quote:

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Originally Posted by CelticDaddio

I forgot to ask this, but I assume I should be running the filter the entire time I have the FC up to kill the algae....Is that right?

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Yes, it would be better if you kept your filter running. Having the filter on ensures that the chlorine is distributed everywhere in your pool and also allows for the dead algae to get caught into your filter. If you only ran your filter part time, as you do when there is no algae, you would still probably kill the algae, but it would take longer (since the chlorine level would drop locally where it is consumed in areas of algae) and would certainly take longer to filter out the dead stuff.

Actually, I keep my filter running 24/7. Is that a problem? Other than running up my power bill?

Ed

Quote:

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Originally Posted by chem geek

Yes, it would be better if you kept your filter running. Having the filter on ensures that the chlorine is distributed everywhere in your pool and also allows for the dead algae to get caught into your filter. If you only ran your filter part time, as you do when there is no algae, you would still probably kill the algae, but it would take longer (since the chlorine level would drop locally where it is consumed in areas of algae) and would certainly take longer to filter out the dead stuff.

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CelticDaddio, Chemgeek and Dawndenise have given you the answers you asked for, but I'll add two things
1) Brush the pool to help expose the algae (espesially in the 'nooks and cranies') to your lethal dose of chlorine - it'll speed things up a little and make sure you kill it all.
2) A 'noodle' hanging into the pool and secured to the deck will allow the 'monks an exit (if they can swim well enough to get to it :D ), if not they stand a chance to be mentioned in the 'Darwin Awards'
Welcome to the forum, as you can see from this thread, there are people here that want you to have a 'hastle-free' pool! :) - Waste

Quote:

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Originally Posted by CelticDaddio

So... if I know the starting pH (and TA and CYA), what is the formula for calculating the target pH given a particular amount of Borax?

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You're going to hate this answer -- it's not a simple formula. I have a spreadsheet that calculates all of this, but it is so complex and scary that it has been known to make grown men cry and teenage girls shriek in horror. If you are a real risk-taker, thrill-seeker, and can close your eyes to all the chemical equations and can live with no instructions or help, you may find this monster by clicking on the link near the end of this post in The China Shop. Don't say I didn't warn you... (HINT: Put in your Initial and Goal conditions and use the "Calculate Acid/Base/TA" button to figure out how much Borax is needed -- this will let the TA value float to match the pH you want while only calculating acid/base and not bicarb. or CO2 outgassing). (SECOND HINT: If you want to see the effect on pH of adding Borax, just put in your initial conditions and the amount of Borax you are adding in the Base section and use the "Calculate pH/TA" button to calculate the Goal values).

Richard

Thanks for the link to the other post... That is just the type of info I was looking for.

Ed

Quote:

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Originally Posted by chem geek

You're going to hate this answer -- it's not a simple formula. I have a spreadsheet that calculates all of this, but it is so complex and scary that it has been known to make grown men cry and teenage girls shriek in horror. If you are a real risk-taker, thrill-seeker, and can close your eyes to all the chemical equations and can live with no instructions or help, you may find this monster by clicking on the link near the end of this post in The China Shop. Don't say I didn't warn you... (HINT: Put in your Initial and Goal conditions and use the "Calculate Acid/Base/TA" button to figure out how much Borax is needed -- this will let the TA value float to match the pH you want while only calculating acid/base and not bicarb. or CO2 outgassing). (SECOND HINT: If you want to see the effect on pH of adding Borax, just put in your initial conditions and the amount of Borax you are adding in the Base section and use the "Calculate pH/TA" button to calculate the Goal values).

Richard

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