Backwashing and shocking

[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

[jmcrae]

OK Janet, got a test kit from Leslie Pools today... here goes:

FC = 2
TC = 3
CC = 1
PH = 7.5
TA = 150
CYA = 70

The pool looked great yesterday. I wasn't able to vacuum this morning and took the readings this afternoon when I got home. Pool's green on the sides and around the base. Now it's raining like mad... we're getting rain bands from the hurricane...

I don't have the filter sock or DE yet.

Thanks again for your time.

Judi

[Watermom]

Hi Judi,
Not Janet here, but hope I'll do!

With a cya of 70, your chlorine levels are not near high enough to keep algae from forming much less to fight it!

Stabilizer . . . . . . Min. FC . . . . Max FC . . . 'Shock' FC
=> 0 ppm . . . . . . . 1 ppm . . . . . 3 ppm . . . . 10 ppm
=> 10 - 20 ppm . . . . 2 ppm . . . . . 5 ppm . . . . 12 ppm
=> 30 - 50 ppm . . . . 3 ppm . . . . . 6 ppm . . . . 15 ppm
=> 60 - 90 ppm . . . . 5 ppm . . . . . 10 ppm . . .. 20 ppm
=> 100 - 200 ppm . . . 8 ppm . . . . . 15 ppm . . .. 25 ppm

As you can see in the chart above, you need to keep your cl between 5-10 ALL the time and when you need to shock, you'll need to take it up to 20ppm. Since you are reporting a CC reading of 1, and you have low FC level and you are seeing algae, all these things tell you that you need to shock the pool and try and hold the cl at 20. The more times per day that you can test and add bleach to get your cl back up to 20 the better. The very minimum is twice per day: early morning and in the evening when the sun is off the pool. But, if you can test 3 or 4 times per day it will clear up faster. The key is to sustain the high cl reading and not let the FC yo-yo up and down. When you get to the point where you are not losing more than 1ppm of cl from sundown to sunup and when you have a CC reading of 0 and no more algae, then you can let your cl drift back down to between 5-10. Never below 5 however or you will fight algae again. Also run your pump 24/7 while you are trying to clear this up. Also, brush the sides and bottom of your pool daily.

What exactly have you added to this pool -- meaning ingredients, not just "shock"? Your cya is already high at 70 so you really shouldn't use any trichlor pucks or dichlor powder in your pool. Best to stick with bleach or liquid chlorine.

What is the volume of your pool?

[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!