Weird Levels

As you can see from my previous posts we have been dealing with mustard algae. Ran out of reagents and were unable to test for 3 days. We continued to add 6% bleach until we got the reagents we ordered. Also added a box of borax since ph was 7.2 Tested at 6:30 pm tonight the levels were as follows:
FC 25.5 CC 0 ph 7.2 Alk ?? CYA 40 Now the question. My CYA was running anywhere from 80 to 95 in all the previous tests. I tested twice tonight to make sure I did it correctly. Same results both times. The alkalinity never did turn red. Lost the green color after 8 drops. Did this test twice also, same results. After 20 drops, I stopped.

By my calculations using the Pool Calculator I should add 9.8 (10) jugs of 182oz. 6% bleach. Can I add another box of borax or should I wait? We still have 10-12 small dime size brown spots in the bottom of the pool but the water is clear.

Found polyquat 60% at the local pool store. Once this mess is cleaned up do you recommend? I definately do not want this to come back. I have the Taylor K-2006 teting kit. For chlorine the reagent is R-0871. The 2oz R0871-C is the same correct? Just a bigger bottle? Thanks in advance for all of your help.

Chlorine level after 2 hours is 60- after 10 jugs of bleach.

Lynn

Help! I really need to know why/how my cya level has dropped and why alk test does not turn red. Levels are as follows today: FC 29 CC 0 ph 7.2 alk ? turned orangish at 75 (same results when I used the 10ml instructions in the test kit) cya 35-40 CYA was 80-90 a week ago I tested twice last night and twice tonight and it was the same. Regarding the Taylor K-2006 test kit. Is the only differece in the R0871 and the R0871C just the size? These questions may seem silly to some but I will get the hang of this. On the bright side, have not seen any more "brownish/yellow dust". Makes us VERY happy pool owners. One last question. Since we had the problem with mustard algae do you recommend the polyquat be used or not? We are undecided on it.

Sorry you haven't gotten responses to this yet--I've spent quite a bit of time on the forum in the last few days and this is the first time I've seen this post--don't know why. Anyway...
The only difference in the R 0871 and r0871c is the size of the bottle.
I'm not sure why your alk doesn't turn red--but I would count the drops until you get the last permanent color change and call it that level. Regarding CYA, other than biodegration by algae or some bacteria, the only explanation that I could offer for lowering CYA is replacement of water--either splashout, large amount of vac'ing to waste, or backwashing the filter. You can backwash out an immense amount of water with a sand filter.

Regarding the polyquat, I don't use it in my pool, but also have never had to conquer mustard algae either. My guess would be that it would be a good thing to use as a secondary defense to chlorine, but I'll let Pooldoc, Waterbear, chem geek, or some of the others chime in with a more informed opinion.

When the chlorine level is very high, the TA test goes from blue to yellow instead of green to red. You might be be confusing the initial blue as thinking it's green or perhaps it's an in between color, but going to yellow makes it look sort of clear. That sounds like what is happening. As for the CYA level, I don't have an explanation for that but I wouldn't worry about it. You'll know if the CYA is really that low because you'll notice higher chlorine loss during the day and after things settle down you can test again if you want.

As for yellow/mustard algae, you really need to get completely rid of it including behind light niches and under removable ladders where it likes to hide out in shade. Also, all pool equipment that contacts the pool water needs to get into the pool. If you want extra protection, you can either 1) keep the FC at a minimum of 15% of the CYA level (though that obviously can become impractical) or 2) use Polyquat 60 weekly or 3) use 50 ppm Borates in the pool. Though I believe the Polyquat may help, I'm not sure about the Borates for yellow/mustard algae -- I know it helps with green algae).

Levels today at 11:00 am : FC 15 CC 0 ph 7.6 ALK 90 CYA less than 30. Last night I added sodium carbonate to raise the ph. I know it can raise alk but as we were at 80, felt it would be ok. Will be going today to get more borax. What do I need to do to raise the CYA levels? Or should I let it be and use the triclor pucks that I have when the chlorine level comes down a little more? Can you swim with the FC at 15 without turning highlighted hair green? Water is clear with no signs of the mustard algae or brown dusty spots. Have soaked EVERYTHING that goes in the pool in bleach. Thanks to everyone that helped us get rid of the mess. Couldn't have done it with out you.

You can just use your pucks to add chlorine and CYA for awhile and then when your CYA hits about 50, discontinue their use and switch to bleach. (But, read the label on the pucks and make sure they are only trichlor. Some have other things like copper in them and you do NOT want copper in there!)

Contrary to popular belief, it is copper that turns blonde hair green and not chlorine. You can swim with chlorine at 15ppm. I won't hurt people but I wouldn't wear my good swimsuit. Take a look at the Best Guess Chlorine Chart in Janet's signature above.

pH at 7.6 is about perfect so don't add any Borax at this point. If you do decide to use the pucks, watch your pH. The pucks are very acidic and will drive the pH down.

Levels today: FC 5.0 CC 0 PH 7.4 ALK 90 CYA 50 Temp 92. HOORAY!!! Clear water, levels good, NO brown dusty spots, not yellow dusty mustard algae. And we did it with out going to the pool store. Well, let me take that back. I did buy some stabilizer since ours was less than 30. Thanks to all who helped us get back in our pool. Could not have done it with out you. I can't believe more people don't do this. How much bleach would you think I will need per week when the pucks come out? How fast will the levels drop? Am I going to have to test everyday? Again, thanks to all who contributed to our nice clean algae free pool.

For awhile, you do need to test every evening while you are getting a feel for how your pool is going to behave. Each time you test, add enough bleach to get to 6ppm. If you find that by the next evening, you have dropped lower than 3ppm, take it a little higher that evening. With a CYA of 50, you never want to let the chlorine drop below 3ppm or you'll be right back where you were with algae!

I have the same size pool as you and I am to the point where I can usually test every other day and when I do, I usually add a small jug (3 quarts) of bleach. That is not a hard and fast rule and it also depends on what the weather has been like, how much swimming we have done, etc. You'll soon learn what your pool is going to need but for now, it is smart to test cl and pH every night.

By the way --- regarding the pucks ---- your CYA is great at 50. You really don't want it higher. Finish up the pucks you have in there and then no more. You'll also need to test your CYA again when the pucks are dissolved and if it is much higher, you'll need to adjust your needed chlorine levels. See the Best Guess Chlorine Chart for more about that.

Good luck and have fun swimming! We are glad you got things turned around! Be diligent about your pool chemistry so you don't have to fight this battle again.

Watermom and I rarely diverge on our advice-giving, but I just wanted to throw something out there....you now have a nice, clean, clear pool, and Watermom has given you great advice about testing daily to get a feel for how much chlorine your pool uses and roughly how much you'll need to add. However, if you feel that you're still using too much chlorine in a day's time (different pools with different sunlight exposure, temps, etc vary in how much chlorine they use), you might try bumping your CYA up just a little bit to see if that slows your chlorine loss any. When you raise your CYA level, you'll also have to raise your minimum chlorine level, but you might find that you lose less chlorine overall with a slightly higher CYA. I run my pool at 80-90 ppm CYA on purpose, because that's the point where I lose the least amount of Cl in a day. It means I have to maintain chlorine levels of 5-10 ppm, but I only lose 2 ppm or so daily, where if I tried to run a CYA of 50 ppm pool, I would lose 4-5 ppm daily. It also allows me to dose every 2-3 days, rather than every day.

Just something to consider.....

Janet

Thanks to both of you. Our pool is in direct sun all day until about 6 pm. Running a slightly higher cya level is something to think about. Will monitor daily for awhile to see how much cl we lose daily.