Backwashing and shocking

[elsie]

Good morning everyone,

My baseline filter pressure is 12 psi. I uncovered the pool June 1 and here it is June 22 and the psi has not changed. The pool stays very clean; the few leaves I've gotten I've fished out with my leaf net. Most debris involves bugs and silt coming down from the trees, and of course it gets filtered with my 1 hp Superpump (sand filter, 20,000 gal in ground). I get a small blob of debris in the bottom of the deep end occasionally and it just takes a minute to hook up my vac hose and take care of it. Of course I brush the pool every week.

If we get no crazy tropical storms this season and my psi stays this low all summer, then theoretically I should not need to backwash at all (I know that dirtier sand cleans better and over-backwashing is hard on the system)? And, if this remains the case, should I backwash anyway when I cover pool in September? Although there will be 8-9 months downtime, I will run pump anywhere from 10-15 times in the overnight hours when temps drop below 28 overnight during the winter months so the pump will not be totally inactive during that time (I live in the south).

* * * * *

With a CYA of 50, when I opened to a crystal clear pool after 9 months down time, I shocked to 15 ppm. Since then I continue to find no combined chlorine. Since I lose about 2.5 ppm a day under full sun I bring the ppm up to 4.5-5.0 each night (with household bleach). So the 24-hour range is 5.0 ppm to 2.5 ppm. I am the only swimmer in the pool most of the time, swimming several times a day, but I think this qualifies for a low bathing load.

Conventional pool advice, we know, tells us to shock every 10 days or so (no matter what), but if I have no CC, and crystal clear water, I shouldn't worry about shocking until I have CC (or signs of algae)? My water is completely odorless and in fact even after swimming there is no trace of chlorine smell on my skin.

One more question: if I get .5 ppm CC should I shock, or wait until I get 1.0 ppm? I apologize that I haven't the time here at work to search the archives. Thank you!

[aylad]

Hi Elsie!

Welcome back--I remember you from "before"....glad to see you've come back to the forum.

Second question first, if your pool is clear, showing no signs of a problem, and not using any chlorine overnight, and you're diligent about keeping your chlorine up adequately, then you could certainly wait until you get 1 ppm CC before shocking--I don't remember where you live, but in many cases the sun will take care of a 0.5 CC before dusk sets in. Almost all pools will have 0.5 at some time, mine almost always does for an hour or so after the kids get out (sweat, sunscreen, dirt off the toys, etc) but it's usually gone by dark. You mentioned tropical storms--I do ALWAYS shock my pool after a hurricane has blown through, though, or after a several-day rain event, even if the numbers are good, because you just never know what the rain will drop into your pool.

As far as your filtering goes, if your pool is very clean, I wouldn't expect your pressure to rise, and I see no need in backwashing it until the pressure does rise. I would, however, backwash it before closing--you don't want all the "gunk" in there from a whole season having all that time to grow bacteria and other stuff that you'll have to kill off when you reopen.

Janet

[elsie]

Hi Janet,

All excellent advice, thank you so very much! I'm in central Alabama (a transplant 8 years ago after 47 years in my native Minnesota). As I recall you're in Louisiana and keep a CYA of 100 because of the nonstop hours of full sun on your pool...funny what things stick in our minds (assuming my memory is serving me correctly). Of course these days the mention of LA--at least coastal LA--conjures up very sad thoughts. Tragic beyond words.

Thanks again for confirming my thoughts on the backwashing and shocking! And I'll "see" you around the forum!

[aylad]

As I recall you're in Louisiana and keep a CYA of 100 because of the nonstop hours of full sun on your pool...funny what things stick in our minds (assuming my memory is serving me correctly).

Yup, that's me! Still down here, oil slick or not

Janet

[jmcrae]

Hi everyone! I'm new to The PoolForum so if my post is out of place, please feel free to move it.

We are having an issue with backwashing and shocking our pool it that we have done it more to our new pool installed four months ago, than we ever did with our old above ground pool. It involves an algae issue but after reading the posts in the algae forum, I decided to post here because in the last 15 years we've had above ground pools, we have primarily use a shock product - and an occasional clarifier product... and never checked any water levels! I vacuumed the pool every other day and my husband backwashed every other week or so. We never had any problems like this before.

I am vacuuming the pool AT LEAST once a day, in the morning, and before the sun sets, the bottom of the pool is covered with a fine green/brown dusting as described in the algae forum. And I have to backwash AT LEAST TWICE before I finish vacuuming!

We will try the DE and filter sock (if I can find one) and I will attempt to find a water tester so I can provide you with the levels. Meanwhile, I need to find some kind of primer on pool maintenance and what all the abbreviations mean and how to deal with each.

Meanwhile, can you tell me if I'm destroying our filter by backwashing so much? (The Doughboy documents are very sparse)

Thanks for your time!

[aylad]

Hi, Judi,
Welcome to the forum!!

For right now, backwashing your filter frequently is much better for it than letting the pressure get too high and overloading your pump. It shouldn't hurt the filter; however, if you're having to backwash that often, there are obviously problems with the water that you need to address.

Does your filter have a vacuum to waste mode? That would allow you to still vacuum but to bypass the filter so the frequent backwashings wouldn't be necessary.


By "occasionally using a shock product and a clarifier product and not testing any water levels", you may have created a pool that's going to take some time and patience to fix, but I'm sure we can help you with it.

If you'll have the water tested with a drop-based kit (no strips!) and post numbers for at least two of the three: Free Chlorine, Total Chlorine, Combined Chlorine in addition to pH, Total Alkalinity, CYA (stabilizer), and Hardness, I'm sure we can help you get the algae problem fixed so that you don't have to spend nearly as much time vacuuming.

We also need the ingredients of the chems you've been using in the pool (specific ingredients, not just "shock").

Also, you really need to get a good, drop-based kit so you can do your testing at home and make sure that your readings are accurate. In order to clear up an algae problem, this is going to be key. We recommend the Taylor 2006K, which can be found online. Leslie's also has a relabeled version of that kit on their online site.

In the meantime, read through the "stickies" at the top of the forums--most of the general water chemistry basics and methods are in those stickies. You can also check out our sister site PoolSolutions.com and there's LOTS of information there that will help you understand what's going on with your pool. And, of course, we're here to help!! It will be helpful if you'll just keep all the information regarding this situation in this one thread, so that all the people trying to assist you have all the info in one place.

Janet

[Watermom]

Joecus ---
I split this thread and moved your question and Waterbear's reply into a new thread titled: Hot climate = Optional high CYA. Please continue there. Thanks.

[waterbear]

Joecus ---
I split this thread and moved your question and Waterbear's reply into a new thread titled: Hot climate = Optional high CYA. Please continue there. Thanks.

Thanks!