New BBB - a few questions about CYA/chlorine and pump time

[giffman67]

I've done a fair amount of reading over the last couple of weeks and feel like I've got a decent handle on the BBB process....but I have a few questions.

30,000 gal pool, Hayward 1.5hp pump, vinyl liner. Live in SE. Pool gets full direct sunlight from 10am until 6pm.

CYA 85
FC 2.0
PH 7.6

I believe PH is ok but based on what I've read CYA is waaay high. I've drained about 2", then refilled. Going to test CYA at the pool store in a couple of hours.

Questions:

FC level is dropping 2ppm per day. Is this drop unreasonable?

It takes approx 1 gallon of Chlorox bleach to raise FC by 1ppm. Does this seem like alot?

The pool store water analysis sheet recommends "30-200ppm" for CYA. 200 ?! Thoughts?

I'm confused about CYA. 30-50 is ideal, but I've read where higher levels 80-90 will "shield" chlorine better. With my CYA as high as it is, why is the pool burning up 2ppm in chlorine every day?

Bough a pump timer and plan to cut pump time from 24/7 to hopefully 10-12 hours per day. (2 hours in the evening when I add chemical and 8-10 hours during the hottest part of the day.) Is this a reasonable expectation?

Thanks in advance!

 

[TaterGun]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Pool stores are notoriously bad at testing, especially the CYA test. You could have taken that same water to a different pool store and received way different results. You need to order a tf-100 test kit and take the water testing into your own hands.

Assuming the pool store numbers are correct, 2 ppm seems a little high. Have you performed an OCLT to make sure something else isn't using up chlorine?

 

[giffman67]

Re: New BBB - a few questions about CYA/chlorine and pump ti

I'm testing FC and PH with the "Basic" Taylor kit and FC, PH, acid/akali demand and TA with a BioGuard test kit. Having the pool store test it about once a week and then comparing notes.

...I said "gallon" of Clorox, it's actually 3.75qt / 121oz.

Thanks.

 

[giffman67]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Read the page on OCLT. I'll try it and see what happens.

So FC can drop as much as 1 ppm overnight and still be considered ok? I figured it shouldn't drop hardly at all.

 

[Richard320]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Read the page on OCLT. I'll try it and see what happens.

So FC can drop as much as 1 ppm overnight and still be considered ok? I figured it shouldn't drop hardly at all.

It just depends on what is in the water. There could be a lot of dead skin cells, sweat, snot, grass, pollen, whatever, that needs to be oxidized. You might find zero drop overnight.

Back to the original post: 2 ppm/day is excellent.
85 is a bit steep on CYA, but if you continue to drain off a few inches (I water my lawn with pool water then refill with fresh) every week, it will come down over time. As long as you get no algae bloom, the high CYA won't hurt anything.

You can probably reduce the pump run time even more. I get by with about 3 hours/day plus whatever extra it gets while I'm vacuuming. Just keep cutting it back every week until it starts to lose some sparkle (chemistry kept in balance, of course) and go back up. Every pool has a unique personality, you just need to learn yours.

Pool Stores use manufacturers recommendations for CYA. If you read here long enough, you will start to see the pattern emerge where the pool store sells chemical after chemical and when the pool finally gets too cloudy or green, they discover your Total Dissolved Solids are too high and recommend draining it. But it's not really TDS, it's saturated with CYA. Here's a little essay I wrote a while ago that describes the pool store scenario.

We'll take a 16000 gallon pool, because that's what I have. On a fresh fill, prominent national pool chain recommends 2.5 pounds pf stabilizer per 10,000 gallons, which works out nicely to 4 pounds which brings CYA to 30.

With an average loss of 2 PPM/Day or 14 ppm/week, I'll have added 8.6 PPM/CYA if I used trichlor pucks perfectly. And they recommend a weekly "shock" of dichlor between 5 and 10 FC.... 2-3 oz per 10,000 gallons. Split the difference; I'll add 4 oz. CYA went up another .9.

So..by the end of week one, I have added 9.5 more CYA. It is now 39.5. Mimimum FC for that is 3, so I'm probably okay.

Week two, up to 49 CYA.
Week three, 58.5. Minimum FC should be 5, but they recommend 3 as ideal, so the pool looks a bit hazy. So I'll toss in a little extra dichlor "shock" to jack FC up to 10. Which adds another 6.4 CYA. Keeping count? We're up to 64.9 now.

That caught the algae just in time.. we had two weeks of good luck. A steady diet of pucks and 4 oz. "shock" each week only added another 19, up to 73.9 now.

Week 6 it started looking funky, so we "shocked"it once again. CYA is up to 99.3. But minimum FC to keep algae at bay is 8, and we're still holding things to 3, because prominent national chain's preprinted sheet shows that as ideal. So algae got a toehold and the pool has a bit of a tint. So we throw two whole bags of dichlor in which jacks it another 7.6 by the time week 7 is over, we're at 116.4, because we had pucks in the floater the whole time.

So...in 7 weeks, from 30 to 116.4. Let's say there are no more algae outbreaks because they sold me a huge bucket of phos-free and another of yellow-out monopersulfate "shock" Nothing but the pucks and the extra 4 oz of dichlor "shock" weekly. So the next 7 weeks added 66.5, which brings the total to 182.9 CYA.

Now if we didn't understand this and things looked a bit hazy, we might throw an extra puck or two in the floater every couple weeks, which will drive it over 200 easily.

 

[jpfuse]

Re: New BBB - a few questions about CYA/chlorine and pump ti

that is the second time i read that essay, and it is depressing to read , because that is exactly what happened to me, and probably to most of the bbb converts here. it is a simple-to-understand scenario of what happens by blindly following some pool stores advice and just throwing in chemical after chemical after.....

 

[giffman67]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Good information. Thanks.

Yep.... been getting hosed for about $150/mo playing the yo-yo game at the pool store. No more.

Just to show you how far off they can be - I had them test the water just for fun yesterday. CYA was 83 the day prior. Without draining/adding any water the CYA dropped to 50. ...and FC showed 6 ppm even though both the BioGuard and Taylor test kits I'm using show about 2.5 ppm.

 

[gatorbrit]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Here's a little essay I wrote a while ago that describes the pool store scenario.

This is my story!!! Clear for a few days - schock, crank up the chlorine from the nature2 and all is good until ... And now I am at 100 CYA!! Fortunately I have a plan and its name is BBB.

 

[BoDarville]

Re: New BBB - a few questions about CYA/chlorine and pump ti

Bough a pump timer and plan to cut pump time from 24/7 to hopefully 10-12 hours per day. (2 hours in the evening when I add chemical and 8-10 hours during the hottest part of the day.) Is this a reasonable expectation?

I would suggest reading this article: Determine Pump Run Time. It was updated earlier this year. Following these methods, I have reduced my pump run time considerably. I generally run my pump for about 30-40 minutes a day when adding chemicals (bleach and MA when needed). And that's in the hot DFW-area summers. Water is still crystal clear. I run it a bit longer after pool parties and after a storm or windy day when there is more debris in the pool that needs to be vacuumed up. of course, I have an energy-hog 1-speed pump. If I had a 2-speed I would probably run it around twice as long but that would still save energy even above & beyond what I'm doing now.