Question about Using Household Bleach

[afdds]

Hello all. I need some help/advice about the the BBB method.

First a little history. I recently moved to Hawaii and rented a house with a pool. I hired a pool service for $150/month. Within a 4 month period I had two major algae blooms. Pool guy was trying to convince me the problem was with the equipment (solar heater, etc....). I took a pool water sample to a local pool store and had it tested. Discovered that my chemistry was out of wack. Go figure! Suggested to pool guy he shock pool and restore pH and alkalinity to recommended levels. He charged me a fortune for the extra chemicals to get it back in balance. For the $150, he was dropping two Trichlor pucks per week and brushing down the walls. Didn't even have to vacume since I have a Polaris robot doing that. Needless to say I let him go.

Now, I recently took over the pool and decided to go with BBB method. Pool looks great but still have some concerns and questions.
I have a 14,500 gallon pool with 100% tile. Currently my pH is at 7.2, Alkalinity is 90, Cyan is 110+. The shock performed in late Nov seems to have eliminated the algae problem for now. I'm using 2-3 oz of NoMor Problems algae preventer weekly, backwashing with my sand filter weekly, and running the pool pump 10 hrs per day. So far so good.

My problem is I'm having a major problem keeping my chlorine levels up. I started by adding 2 cups of 6% bleach, raised that to 4 cups a day and now 6 cups daily. I'm trying to achieve a chlorine level of 3-4 since my Cyn levels are so high. My assumption was that the chlorine levels would maintain since I have so much stabilizer but I haven't been able to get it over 2ppm yet. Furthermore, I seem to lose chlorine faster than I can add it. When I decided to start using bleach, it was due to desire NOT to add any more Cyn to the pool. Trying not to drain with intent to bring Cyn levels down slowly through weekly backwash and normal draining due to high amounts of rain recently. Unless I have further problems with algae blooms, I'm hoping not to have to do a major drain (50% of pool) and refill.

My question: Is it normal to have to add 6 or more cups of Chlorox daily? Shouln't my chlorine hang around awhile with so much stabilizer already in the pool? What is the "normal" amount and frequency expected to add chlorine bleach in order to maintain a 3-4 ppm level?

Look forward to hearing your reply and advice!

Jeff

 

[dmanb2b]

Jeff...welcome to TFP

An FC level of 3-4 is too low if your CYA level is truly 110+. Having stabilizer that high would have me suggesting a partial drain and fill to lower your CYA level to a maximum of 70ppm (we usually recommend 30-40ppm in a manually dosed pool, but if you are getting alot of aloha sun, 70ppm is manageable). The NoMor algaecide is not required but has probably helped you some since your FC is too low. The bad news is that once algae take charge, the algaecide is basically useless as it can't kill it fast enough. That is your chlorine's job

Regular unscented household bleach is a great chlorine source, but be advised that it can come in varying concentrations (3%, 5.25%, 6%). Pool store liquid chlorine is the same exact thing except the concentration of sodium chlorde is 10.5% or 12%. One gallon of 6% bleach will raise the FC in a 10K gal pool by 6ppm (12% bleach in a 10k gal pool = 12ppm...etc). You can use the poolcalculator.com to figure out your correct dosage.

Shocking is a process, that involves raising your FC to a high level relative to your CYA level, not a product you can purchase (marketing term). Having CYA at 110 makes shocking, extremely difficult

Take a read through pool school (button on upper right) and do order yourself a testkit such as the TF100 from tftestkits.net or the Taylor k2006. We tend to like the TF100 as a better overall value, but not sure if you have high shipping costs to HI. With a testkit and reading through Pool School a few times, you will have this under control in no time.

 

[afdds]

Thanks for the reply. The previous shock was achieved by adding 9lbs of dichlor and while I didn't have the Taylor test kit and didn't follow the process as described in "Pool School" it appears to have been effective. I do know that the Chlorine level following the "shock" remained above 5ppm on my cheapo test kit for well over a week. Considering I haven't seen any additional algae, I'm assuming that it was effective.

Getting back to my origional question, using the BBB method, should I expect to add chlorine bleach daily (Using 6% Chlorox)? Would this be the norm? My wife and I are debating whether to continue using BBB, as she thinks daily testing and adding bleach is too much hassle and would prefer to stick with tabs. I now understand the implication of using tabs and would prefer to stick with BBB but haven't yet found on the forum what to expect in terms of frequency and amount of chlorine I will likely have to add. If it's easier, take my high CYN levels out of the equation.

 

[dmanb2b]

Your welcome I hate to do this, but...It's really really really hard to take CYA part out of the advice, since it is part of the BBB formula. Shocking with Dichlor is what likely raised your CYA level to 110+ (Dichlor and Trichlor pucks raise CYA, Calhypo raises CH). To answer your specific question, with CYA levels that high, you will have to test your FC level often and keep it above 10ppm, or the algae will be back. FC of 5ppm is not sufficient, given your CYA level. At more reasonable CYA level, with a good test kit, when you get really good at knowing your pool water, there are folks who go 2-3 days between bleach additions, but you have to know how high you can safely increase your FC levels.

BBB is really about accurate testing and knowing what's going on with your water and how to correct, rather than just adding bleach. The bleach part can be automated, if you wish, by using a liquidator or saltwater chlorine generator. But the requirement to test your pool water often remains, regardless if you use pucks, bleach, baquacil...etc. Most folks like to think, all I have to do is chuck a few pucks and I'm done, but as you now know first hand, it is far from the truth

Again...sorry for bringing up CYA again, but disregarding it will allow your DW to win this debate...for now.

 

[dmanb2b]

Also...one gal of 6% will raise your FC level by approx 4ppm (15k gal pool). Average FC burn rates run anywhere in the 1-4ppm range per day. To skip a day of bleach addition you would have to add more than you burn off on the days skipped

 

[Beez]

I manage my pool with bleach additions only a couple times a week, so yes, it can be done under certain circumstances. Sun exposure and bather load are the 2 biggest factors in FC depletion. In my case, the pool gets a lot of shade and I don't use it every day.

If your pool is in full sun all day you may have no other choice than daily additions. Also, if I swam in my pool every day I would insist on daily testing and additions. It really doesn't take much time once you're in the groove...

Just my $.02,
Dave

 

[Ohm_Boy]

Hard to say how normal that chlorine loss is, because there are too many unknowns at this time. My gut feeling is that you have some organics consuming chlorine in your pool, and you'll need to perform a shock to eliminate it. Alas, I do not believe that you have the tools needed to elevate the FC to necessary levels and be able to determine whether overnight loss is within acceptable levels. A FAS-DPD test is needed to test for chlorine at those levels, and is probably the only test with the precision to detect a 1 PPM loss.

9 lbs of Dichlor should have kicked your FC level up by over 40ppm, so no doubt it would stay over 5 for a while. It also would have bumped the CYA level by 38 or so. Those Trichlor pucks that your former pool guy was using were also constantly adding CYA.

I have concerns about that CYA level. Most CYA tests max out at 100, and levels above that simply read as 100, whether the level is 100, 200, 300, or whatever. Do you know what type of test was performed?

My immediate suggestion would be to get a good test kit, such as our TF-100 or the Taylor K2006, and get a proper assessment of the water chemical situation, and to perform an overnight FC loss test. Then we could set you onto the path to a trouble free pool.

 

[Richard320]

What they said: you need a test kit.

I had a pool service that did pretty much the same as yours, until I wised -up like you did. They left me with CYA somewhere around 220-240. Fortunately, I had no algae outbreaks. But I did have to dilute my samples 3:1 with tap water to measure CYA and FC. Then I sprung for a TF100, and the FAS-DPD chlorine test, and was able to measure and adjust FC using that. It is possible to maintain the pool chemistry with that high CYA - I am proof of that. With rainwater, draining and refilling, etc, I now have CYA down to 55, and I'm hoping for more rain. Soon. Your situationm is different, you have algae in the mix. Probably growing behind the light or in the filter, and you're killing it at the same rate it's growing, so you don't see it. You'll probably need to drain and refill some, to facilitate shocking.

My pool never looked bad, but you ought to see it now. The water is so clear, when the pump's off and the surface is still, it's hard to tell there's any water in it!

Just bite the bullet, order a TF100 and a speedstir (you'll thank me for that, I promise). Even with shipping to Hawaii, it'll be less than one month of crappy pool service.

While you wait for the kit, read Pool School. And bookmark the pool calculator.

 

[beezar]

What they said: you need a test kit.

I had a pool service that did pretty much the same as yours, until I wised -up like you did. They left me with CYA somewhere around 220-240. Fortunately, I had no algae outbreaks. But I did have to dilute my samples 3:1 with tap water to measure CYA and FC.

Don't mean to hijack the thread, but I also have very high CYA levels (> 100 per the TFTest Kit). Are you saying if I dilute my pool water 3:1 with tap water, do a CYA test on it, I can get an accurate number by multiplying the resultant test result by 3?

 

[dmanb2b]

It will have 3x the margin of error (normally +/- 10ppm) so you figure you could estimate it to within 30ppm +/- using the dilution method richard suggested.

 

[JasonLion]

A 3:1 dilution increases the range by four times (multiply the result by four) and multiplies the error by four times. Also, the error on the CYA test is only +-10 if you are very good at it. For most people it is more like +-15. That means a 3:1 dilution gives an error of more like +-60, which is a pretty big range, ie low precision. It is much more plausible to do a CYA test with a 1:1 dilution (multiply the result by two), assuming you really need to, but I don't normally recommend diluting more then that.