Please help with test results, etc.

[meeko350]

I have an above ground 30 foot round vinyl pool with 52" walls. I'm in Louisiana with full sun all day. Pump & fountain runs continuously. I've already stopped using the chlorine pucks so the cya won't climb anymore. We had an enormous amount of rain last week and I haven't added any chemical since then, but did have to drain water several times and I vacuumed out the mustard colored algae. Any other background info needed? I tested using the K-2006 FAS-DPD kit and can't figure out the included wheel chart.

Ph 7.4
TA 60
FC 4.4
CC 0
CYA 88
Calcium 60

How much baking soda should I add? And what will that do to my ph? How much borax should I add?

At what level do I need keep the chlorine since my cya is so high? And was the algae caused by the rain or my cya level? I didn't notice it before the rain.

Thanks for your help!

[aylad]

Hi,

You don't need to add any baking soda(that raises TA, and yours is okay where it is) or borax (that raises pH, and yours is fine). You need, with a CYA of 88 (where did that number come from? If it's from the K-2006, then just round it to 90), to be keeping your chlorine at an absolute minimum of 5 ppm, and you're on the verge of having to jump up to a minimum of 8 ppm. Considering the amount of rain you've had to dilute the chlorine, and the fact that it's so low now, it probably needs to be shocked. For a CYA of 90, that means bringing it up to 20 ppm and holding it there until you can measure chorine at night and again in the morning at sunup and not lose more than 1 ppm of chlorine.

The rain didn't cause the algae--more likely, failure to check and maintain chlorine levels during the rain, combined with your high CYA with low chorine, are what caused it.

Where in Louisiana are you? I'm close to Shreveport...

[Watermom]

With an AG pool, i wouldn't worry about the TA if your pH is pretty stable. Your pH is great at 7.4. So, you really don't need baking soda nor Borax at this time.

How do you know you have algae? You report a CC reading of 0. Not always, but usually when you have algae you'll have a CC reading.

With a CYA of 88, you need to be keeping your chlorine level between 5-10 all the time and your shock level when needed is 20ppm.

Test your chlorine tonight when the sun is off the pool and then again in the morning within 2 hours of sunrise. (Test FC and CC both times.) Report back how much FC you lost overnight and what your CC reading is. Then, we can help you determine what your next steps are.

How does the water look?

Please complete our new Pool Chart form -- it takes about 30 seconds, but will save much more than that.

Pool Chart Entry Form

EDIT: Here we go again, Janet, playing tag and answering posts at the same time. You beat me this time!

[meeko350]

Aylad, I'm 10 minutes outside of Monroe. The CYA was a little under the 90 Mark, so I estimated.

Watermom, my water looks great, so it may not have been algae. It was a very fine silty substance and it was yellowish tan. I vacuumed it on Monday and it hasn't returned. I shocked it to 14.5 ppm the day before the rain started and then it rained several times a day for almost a week (very unusual here). My TA was 90 before the ring spree.

So test tonight and in the morning before I shock it? Or shock it first?

[aylad]

I know I'm late with this answer, but the idea is to see if there is chlorine loss when the sun isn't out, so it doesn't matter whether you shock , then take the night's reading, or don't shock, take the night's reading, and then shock it AFTER the morning reading. (Won't tell you anything if you shock it between the night and morning tests). However, with the amount of rain you've had, and the high stabilizer, I would go ahead and shock it as soon as possible. I run my pool with CYA of 90-100, and if I left my Cl at 4 or lower, it wouldn't take more than a day or so before it would start clouding up.

Janet

[famousdavis]

Interesting thread. After one year of pool ownership, I've settled on keeping my CYA around 70-ish during the summer, and using the rule-of-thumb that FC should be no lower than 5% of your CYA reading, I'm keeping my FC around 3-4. My pool equipment manufacturer says that FC shouldn't be greater than 3.0 or it can cause pool damage to the pool equipment. I don't know whether that's foolhardy advice or not, but since the equipment is still under warranty for 2 more years, I'd rather play by Jandy's rules. Since I've had my pool, the only problem I've ever had was pink slime started growing on the grout sometime late last summer. I bumped up the FC until it went away, and so far, it hasn't returned. The water has always been very clear, and the CC has always been between 0 and 0.5. So, my pool conditions are similar to the OP's, in that our pool's FC is both hovering right around the 5% of CYA mark -- but my pool hasn't had any trouble yet.

Could the yellow stuff be pollen?

[aylad]

The yellow stuff could be pollen, but we won't know until we see if there's a chlorine demand overnight, which is why we're advocating the overnight testing. If this OP loses chlorine overnight, then it's not pollen., it's something in the water eating the chlorine, and that thing must be killed!

There's a difference between your pool and the OP's, that will allow you to keep your FC levels a little lower than the best guess chart requires, and that's your use of the SWCG. When you have a SWCG, you're getting pretty consistent chlorination throughout the runtime of the unit, without the "peaks and valleys" of manual chlorination that happens only once or twice a day. That chlorine consistency allows for a slightly less overall chlorine level with no problems.Those folks who use chlorinators have that advantage as well, except that at some point with a chlorinator the CYA gets too high for the unit to put out enough chlorine--it can't be dialed higher than its max--to keep up.

Janet

[famousdavis]

The overnight test you and others are advocating as a debugging test is something I hadn't noticed before when I first starting coming to this forum (I'm sure the advice has always been used, I just didn't pop into any threads where I saw that advice). A few months ago, I saw that suggestion given so I've periodically taken an evening reading an a morning reading just before the filtration starts-up, to see how much chlorine I've lost. The difference has always been 1 or 0.5, so that's given me confidence that all is well with our pool.

You're right that the SWCG keeps the chlorine consistent, but when we had a high bather load recently, I was surprised at how the chlorine level dropped! Usually my SWCG is between 50% and 70% (running 8 hours a day), but I wound up putting it at 90-100% to bump up the FC level back to >= 3; it had fallen to about 1 after a lot kids and swimming. With just my family in the pool (4 of 6 of us who use the pool frequently), I can generally keep it at the lower percentage.

[aylad]

Yeah, "people goo" will use up a lot of chlorine. We don't normally advise folks to shock the pool on a weekly basis "just because", like the pool stores do, but after a few days of especially heavy bather load (especially if the swimmers are under 10 years old), even with my chlorine in the right range, I still will shock it.

Janet

[famousdavis]

Not shocking a pool on a weekly basis was one of the best pieces of advice I learned from this pool. As a new pool owner, I began by using the "shock" setting (100% for 24 hours) on my SWCG, but I'd have to remember to run the pump after the scheduled off time, and then the pool would stay at a high chlorine level for most of the week, only to be shocked all over again the following week. Very shortly after becoming a pool owner, though, I learned here that shocking is used to get rid of high CC, but if CC levels are low (0.5 or less), it's not really necessary. So, I don't ever regularly shock my pool.

Like you, aylad, I do kinda shock my pool now if I know it's going to get a lot of heavy use. But instead of adjusting the SWCG, I just pour in a 1.5 gallon of grocery store bleach before the hordes of kids come over -- I can't say for certain that that's really necessary, but it makes me feel good about re-entering the pool after everyone's left and gone home again. :-)