Help, even bleach disappears

I have read many posts about shocking to kill algae and ben's best guess chart. I have tried to follow it but I can not get chlorine to stay in pool.
28k vinyl
FC 4(after using 17 Gals 8.25% bleach over past 2 days, plus 15 or more bags shock)
CYA 70
TA 100
ph 7.4
Goldline SWCG
All this year I have had to supplement with chlorine. Since I am a 12 year SWCG user, it is difficult for me to remember to add chlorine. Like I said, I have added 17 gals before today 9added 4 more today and 4 bags shock as well. Have not made new reading yet but so far, the highest I could get the reading was 12 and that did not last long. I saw new algae starting to grow at the base of the liner today even after the 17 gals of bleach. I am thinking that I have had an algae problem all year but was able to stay one step ahead of it and keep it from getting bad enough to see. Then I went out of town for a couple days and when I cam back it was growing everywhere although the water was not green, just cloudy. That is when I started adding the bleach, setting my goal at 20 ppm. Only I never can get there. The most I added at one time was six gals and a few bags of shock. Is my problem that I still have enough algae to destroy the chlorine I keep adding? Is it simply that I should have added enough to get to 20ppm all at once no matter how many it took? It is difficult to buy that many at once and scary to put that many in the pool at once. PS. for years, even when the water is clear and the pool looks good, I always have black or dark green algae in the grooves of the liner clips around the steps. Is this normal? I have to get a stiff bush mounted on an extension to get the stuff out of the clip grooves but it always comes back. Oh, yes and I have had to backwash de filter twice in past week. Today, I took it apart and cleaned it out really good, just in case any algae was hiding in there.
Update, after adding 4 more gals bleach today and 3 bags shock, I finally got the chlorine to read somewhere between 16 and 20. Hopefully I am on the right track now. How long do I need to keep it at this level?
Any advice will be greatly appreciated,
Brent

First off: What are you testing with?
How big is your pool? Cannot estimate how much chlorine you need without that.
What is the ingredient of your "shock"? We HATE using "shock" as a noun rather than a verb here, because as a noun it can be ANYTHING--Cal-hypo, di-chlor, tri-chlor, lithium, "non-chlorine shock", sodium hypochloride. These things all add chlorine (except the non-chlorine) but add other stuff as well.

Plus, if you have algae, you have to kill it before the chlorine level can be maintained.

Sorry Carl. I tried to give all the relevant info. I did say 28k vinyl. 28000 gallons that is. Also the bleach 8.25 percent sodium hypochlorite from walmart. The shock is from walmart as well "pool essentials" and is trichlor. I am testing with the Taylor kit as recommended here, don't remember the exact numbers of the kit, but uses 5 drops 0001 and 5 drops 0002. You know the one that turns pink rather than the cheaper ones that turn yellow.

Sorry, missed the first part.
What you are describing is a DPD chlorine test kit, vs an OTO test kit. DPD bleaches out at above 10ppm but usually around 15, but maybe sooner. The DPD Taylor kit is K-2005, not the K-2006 that we recommend. The difference is that the K-2006 uses the FAS-DPD chlorine test, not the DPD test. FAS-DPD can test to 50 or even 100ppm, and uses a powder first, then a liquid in a brown opaque bottle. The powder is, R-0870 and the brown bottle is R-0871.

If you're throwing in bags of Tri-chlor powder then I'll bet your CYA is now far higher than 70ppm. Trichlor adds 6ppm of CYA for ever 10ppm of chlorine. Stop using it. Don't use Di-chlor powder either.
If your Calcium level isn't too high, you can use cal-hypo--but the WalMart stuff is 48%--worthless. You'll need something over 60% or more.

So...Here's what I am GUESSING is going on
1) You're bleaching out a DPD chlorine test
2) Your CYA is now much higher than you measured, meaning, your chlorine isn't anything close to shock level for the CYA level.

Somewhere around here we have a key to the darker colors of the OTO (yellow) test kit. If you have an OTO kit, using distilled water you can double, triple or quadruple its range. And if it goes to "5" for chlorine, that means you can measure to 10, 15, or 20ppm.

Just mix equal amounts of pool water to distilled (I like to use a shot glass) and mix. In the OTO test if it says "5" it is now 10. If you mix 2 shots of distilled to one of pool water, "5" means 15. 3 shots--20.

That is what I was doing with my test kit. I took 4 ounces of pool water and added 12 ounces of tap water from the faucet (I know should have used distilled). Then I tested it to read around 4. Multiplied the 4 times 4 and translated that to read 16. Does this not work with that type kit? Even if I use distilled water? What about Kroger purified drinking water? I do not have the OTO test kit. I would be more likely to order the reagents you described above. Where can I get cal hypo?

I don't know that dilution works with the DPD test. And, you should test the tap water FIRST before you use it to dilute...if it has a chlorine level it will add it. Same for the Kroger water.

Distilled water is sold in every grocery and chain drug store, so it's easy to get. Also, OTO kits are sold just about everywhere. But the BEST that is sold in retail stores is at Leslies--it's Taylor's own OTO kit, in a Leslie box.

Another really good one is the HTH 5-way drop test kit sold at WalMart (may be called a 6-way drop test kit now). It's an OTO kit as well but it's tests for pH, TA and CYA are pretty much as good as Taylor's.

The FAS-DPD test is sold as a stand-alone test by Taylor. I believe it's the K-1515--and using it with the K-2005 for the chlorine test instead of the DPD test makes the K-2005 the same as the K-2006.

Cal-Hypo powder is sold in pool stores, including WalMart (but not the stronger stuff).

There are Leslies stores all over the Atlanta area, but only one inside the beltway.

It's not that I'm a big fan of Leslies--but that they are the ONLY ones that sell exclusively Taylor drop test kits, even when they are badged (and overpriced) as Leslies own. And the quality of their pool chems is usually good, if also overpriced.

Personally, I found a store years ago that sells 12.5% Liquid Chlorine (same as bleach only stronger) in 5 gallon carboys for $20. They cater to pool maint services so their turnover is tremendous and their stuff always tests at 14% or higher. I use that. They are a good drive but I combine errands when I go there--Orthopedist, electronics supply store, Harbor Freight, better Home Depot than my local one, etc.

ok, you were right. My test shows cya at 100 now, maybe a little higher. It is cloudy now and drizzling so the sun is not out. I tested again using Kroger purified drinking water, sorry forgot to buy distilled when I went back to Kroger for more bleach. My test showed around 20 ppm chlorine and like I said 100 on the cya. I am a few inches short on water level right now so I am hoping these several days of rain predicted will refill it for me. If not when I top off I will dump a little and get the cya down to around 80 again. I noticed you did not comment on the algae I always seem to have in the liner clip around the steps. I assume this is not normal but I have had it for years. Also, a co-worker has a similar set up as mine, de filter, goldline swcg, but 40000 gallons vinyl to my 28000. He claims to run his pump and swcg only 6 hours per day. I have to run mine for 12 to 14 hours and still have no chlorine. He claims to read a constant 4 with his system and run time. Is this possible? The Hayward people told me that the t15 system would have to run at 100% 24/7 to make enough chlorine to keep a 40000 gal pool at 3ppm. He told me that mine should then have to run about 28/40(or 16.8 hours) to keep my pool at 3ppm. If this is true, it makes me want to run dual swcg systems so I can cut down on the run time. With the above readings, have I reached shock level at 20ppm? Do I need to dump some water tomorrow and do the whole thing over again with a lower cya? Thanks for all your help by the way!

Ok. I'm not an expert on persistent black algae, but I can tell you that you need to get your chlorine level up even further, to 25, and keep it there for a number of days before it will stop crashing on you.

Will it get rid of the black algae? I don't know, but you need to brush it daily to have a hope.

I cannot really comment on what Hayward told your friend as it makes no sense whatsover and something must be garbled in translation. There are just too many inconsistencies. I'm no SWCG expert either but I know enough. The t-15 is their biggest cell, designed for pools up to 40K (though you usually want to go bigger than the pool). 3ppm of FC is the normal production level for just about any SWCG and should be matched with a CYA of 60. For the cell to have to run at 100% 24/7 to produce that just doesn't add up. Do you both have the same controller as well?

Ok, I have five new gallons of bleach. I will go back down and bump it up to 25 or so. These several days of rain may come in handy to keep the sun at bay and allow me to pull this off. The Hayward story came to me directly from the Hayward tech support via a phone call. The story about my friend was the fact that he runs his for six hours, and yes we both have the goldline aquarite system. He runs a Hayward cell and I am running a compupool, that is the only difference other than the size of the pools. I have run Hayward cells in the past and I have not seen any difference between the two, other than price. Maybe I need to go back to the brand name cell, who knows.

My chlorine held at the 25 mark overnight. I got in the pool, reluctantly, with a small brush and went around all the fixtures(lights, returns, skimmers, rope hooks, and steps). All of them had algae, both green and black. In some cases long strips of black or dark green stuff were brushed away. I have seen this before, but I thought it would be good to clean it off while the water is at shock levels. I also snapped the covers off the tracks around the steps and cleaned them with the brush. I added one more gallon of bleach for good measure. I am going to do some research on this forum about the black algae. I have not addressed the cya issue yet, but it is raining now and hopefully that will dilute it some. My concern is whether I have a high enough shock level and how long should I maintain it at that level. I would like to be ready for swimming by Saturday.

Actually, the chlorine won't hurt you at that level, but you will want to wear old suits that you don't mind being faded. And you probably don't want it in your eyes so goggles are a good idea.
If the level holds at 25 overnight for a couple of nights, I'd say you're good to go. But with the CYA at 100, you'll need to keep the level between 8 and 15 even while swimming. If it goes down to the 60-90 range, chlorine should be kept between 5 and 10.

Algae is VERY resistant to chlorine when it's attached or embedded in the walls and crevices of the pool. Brushing it out was a VERY good thing! And you should plan to do it regularly, like weekly, to control it.

Hope this helps.

Took a sample to Leslie's this afternoon. CYA read 90. This was after I drained about six inches of water yesterday and refilled. My chlorine was down to the 16 to twenty range also. This was with my test using the dilution method. Actually I ran it with a 1 to 5 ratio and it appeared to read about 4. Not very accurate but that is as close as I can get. I guess I am going to let the chlorine slowly decrease now and see where I stand. My concern is that the SWCG will not be able to keep the chlorine in the 5 to 10 range as you recommended. If that is the case, I guess I will continue to supplement, with cal hypo this time, until I can drain more water and refill to get the cya down further. Thanks, Carl, for all your help. I should have known better. I sort of blame Leslies for the incident because their guy acted like I was crazy to use bleach several days ago. He said since it was only 8.25 percent bleach that it was 91.75 percent something else and that was bad for the pool. That caused me to decide I would use some shock with the bleach. Also the heaviness and difficulties transporting the bleach added to this flawed response. As much as I have read on this forum, I really should have known better. Thanks again!

Oh, wow!

Here's how I can help:
1) When your water is clear, you generally aim an SWCG to run at 5% of the CYA level--because it's a constant flow of Chlorine without ups and downs. Since most SWCGs request you keep your CYA in the 60 to 80 range, you'd keep your FC (that's Free Chlorine) in the 3-4 range. With your CYA at 90, that means you should keep it at least at 4.5--you've cleared up all the rest of the problems so you are going into maintenance mode--normal, daily care.

2) When you do NOT have an SWCG, the "Best Guess Table" is our/your guide, ie, the range I gave you. And, if you have an algae bloom, you do NOT want to use "Boost" mode from the SWCG as you will shorten your cell's life drastically. Best to use bleach or liquid chlorine. Safer, cheaper, extends the life of your cell.

3) You can find the "Best Guess" table at our sister site, PoolSolutions.com. You don't need to join, but I suggest you read EVERYTHING you can find there. It's an education in itself.

4) The Leslies guy is full of it. Bleach is made from brine so the OTHER 91.75% of it (assuming you are using regular bleach) is...SALT WATER! Yeah, that's right. And if you use nothing but bleach for 10 years in your pool you STILL won't have enough salt to run an SWCG. People without SWCGs add 50# bags of salt frequently because it makes the water feel softer. There's not nearly as much salt in bleach or liquid chlorine. Did he also try to "Pool Store" you and sell you "Phosphate removal" and calcium? If you know what you are doing, IMHO, they have some of the best supplies of any chain. If you don't, the salesmen/women may WELL try to sell you garbage--I've heard the "other stuff" argument from their people before. Buyer Beware!

5) Liquid Chlorine (LC), sometime sold in gallon jugs as "Liquid Shock" is nothing more than strong bleach, nominally 12.5%. I buy it in 5 gallon carboys, for $20/gallon. My deposit of $6 on each carboy(I have 3) was so many years ago it doesn't matter. I have a couple of screw on spigots, which are like an old-fashioned beer barrel tap, and I refill old bleach bottles and reuse and reuse them. Since bleach is has gone from 6% to 8.25%, the calculation is: If a gallon of LC is less than 50% higher than a gallon of 8.25%, the LC is cheaper to use. Otherwise, the bleach is cheaper. When 6% was the "Ultra Bleach", the ratio was double--LC could be up to 2x the cost of bleach to be cheaper.

6) If you use Cal-Hypo, track your Calcium Hardness. When it gets to 400ppm, you should stop using the Cal-hypo. When it hits 500ppm, I would say you MUST stop using it or risk your water going milky and getting scale on metal parts. Personally, I rarely use the stuff and only use Tri-Chlor in the spring or when I refilled so I could boost my CYA at the same time as my chlorine. But I also watch pH as Tri-Chlor is VERY acidic.

7) While you can ALWAYS use bleach or LC, Cal-Hypo, Tri-chlor and Di-chlor all add stuff you have to watch. Used correctly, they are beneficial. Used incorrectly, they can cause problems. Test, test, test!