Need advice from swimming poolers - chlorine levels

Factual Questions
1

Ok. Here’s the deal. I will start off by saying this is the first full summer I’ve had the pool, so I’m not quite sure I’ve been doing everything right.

That said,.

I have a in ground, vinyl lined, 20,000 gallon pool. Up until last week the water has been pretty good. We get a small amount of algee on the sides but a shock treatment clears it up.

I’ve not had a problem holding a ph of 7.0-7.4.

I’ve got a rather large sand filter (not sure of the gallons). I backwash and rinse the sand filter about once every 3-4 weeks.

The pool temp has stayed between 76-80f without heating it.

Ok,. here’s my question. Why is it so hard to keep the chlorine level even at 1ppm? I’ve been keeping about 4 of those 3 inch chlorine tablets in the floating dispenser and it doesn’t seem to do anything.

About once every 8-9 days I give it a shock treatment.

Normally it’s just my family (3 people) using the pool, sometimes my daughters friend. Even then it’s only used an hour or two a day on the average. There is no use of suntan oils around or in the pool.

We had a bit of an algee bloom this week (I’ve been kind of busy so I didn’t have any time to do anything for it). Yesterday I finally had time to head over and pick up some shock. I bought some “super sock it” with 78% calcium hypochlorite. I add enough shock for 24,000 gallons (two packages).

This morning I take a look at the pool. It’s cloudy and ugly looking. At least the green is gone. I do a test on the ph and chlorine. ph is at 6.8, chlorine is at 0ppm. 0ppm?!?!. I added a bunch last night.

So, what is eating up all the chlorine? Am I missing a trick to maintaining a good chlorine level or is that the trick of having a pool?

2

It’s possible that your test went bad. Sometimes that happens with those chemicals. Are you using the same bottle from last year? I try to get a new one at the beginning of every summer.

Heat is a big fact. The hotter it is, the more the chlorine will evaporate.

You shouldn’t have to shock it that often. I’ve only shocked my pool twice in the 3 years I’ve had it and once was because I my wife and I were both sick in the early fall and we never closed it properly. We had to shock it at the beginning of the next summer.

Do you use liquid chlorine as well? You only mention the tablets. I keep about 5 or 6 1 inch tablets in my floater and still add about a half a gallon of liquid every once in a while.

3

I just bought a new test kit the other day. I suspect it’s good.

I’m not using any liquid. Just the shock and the tablets.

4

Here is your problem (it’s an easy one):

You need to stabilize the water. Stabilizer protects the chlorine from sun loss and other losses. Without cyuranic acid(stabilizer), the chlorine is unprotected…and will diasappear really fast!

Second, filter should be going 8-10 hours per day, and ONLY BACKWASH when the pressure in then filter is 7 psi higher than it is when the filter is fresh and clean (or check the manual for yours). Sand filters need debris to work at the most efficient…a totally clean sand filter is actually less efficient.

Now TOO MUCH stabilizer is bad too, because it will totally capture the chlorine and the chlorine won’t work. So add the right amount! Top end test strips, top end test kits or pool centers will give stabilizer levels! It’ s a MUST to adress this.

SHOCK: Shock every 7-10 days! Just like you bleach your whites, even though they look decent, for sanitary reasons SHOCK WEEKLY! At night! It’ smart maintenance and if you get all your chlorine from tablets (tablets contain stabilizer), then you are going to have too much stabilzer by years end (assuming you adress the stabilizer issue now). Usually, from backwashing and splashing, you are knocking out some excess stabilizer from all the tablets.

So, in summary:

GET STABILIZER LEVEL CHECKED AND ADDRESS IMMEDIATELY
SHOCK WEEKLY, at night - for sanitary reasons!
Chlorine does NOT WORK if Ph is off! Double Check!
Run the filter 8-10 hours at a minimum per day
Backwash a sand filter only when needed!

5

I used to have a regular pool & we had to put in muriatic acid. Why would your pool not require that too?

6

also, if you are shocking in the presence of algae, the shock will be used on the algae and be used up.

I have a 20,000 gal pool, in groun, liner, sand filter, in NE USA.

If I had some algae, and hit it with two bags of shock, the shock (which is chlorine…hypochlorinate) would die as it fought the evils of alage and bacteria and would have died a valiant fight.

Two bags of shock is MAINTENANCE…which implies you are dumping it into an alge free pool to keep it clear and kill stuff that hasn’t expanded into a visual problem. Once you see algae and other nasties, the two bags of shock are like two bags of ammunition in the fight. They took out the enemy, but there isn’t any left over.

Read my earlier post. Get the stabilizer level checked. Run the filter ‘continuously’ in the presence of algae (and dead algae…the cloudiness/particles hazing your water).

If my pool gets a little behind, and I shock it, it’ll whack the algae, but the filter will run for at least 12 hours, maybe 24, to get all the dead stuff out.

I spend very little on chemicals each year, and you should be in a similar situation.

7

I have a fairly new 9000 gallon pool; cartridge filter, ozone, and automatic chlorine/mineral dispenser (FROG brand).

I’m to change the chlorine cartridge, maintenance shock (one packet) and administer 4 oz. “Back-Up” brand algicide every two weeks during the swim season, every six weeks when cold.

I’ve been told that if I have an algae bloom, neither excess chlorine nor additional “Back-Up” would treat it; I’d need to bring in a water sample to have the algae identified for an appropriate treatment to match.

Can you bring a water sample to your friendly neighborhood pool store? Many do free testing of all this stuff - stabilizer, algae, etc.

8

I was in my pool just a few hours ago. I have an in-ground w/vinyl liner (about 25000 gal.)

I was fortunate in 1999 when I bought this place that I have a good friend who has a gunite pool and has been taking care of it for years. He has advised me and I will share his (and now my maintenance philisophy).

Pools turn (change colors slow- they come bakc slow - a day tto a few days)

You don’t need anyghing but chlorine tablets and liquid chlorine (alghough I am considering switching to the powder from liquid)

  • muriatic acid to raise ph and potash to lower ph and you won’t use much of either.

For testing use the “taylor Basic Pool and Spa Kit” no numbers just match the colors.

I used to use the canister on the line next to the pump made especially for the chlorine tabs - now I just keep 2-4 in the skimmer.

I use the liquid chlorine to “shock” the pool and I try to hit it with
a cuple of gallons after a rain - or maybe before the rain if I knowit is coming that night.

Keep the pool clean - if it starts changing color - hit it with the liquid chlorine

if you want to up the chlorine level immediately - use the liquid

susshine eats chlorine- if power is an issue run the pump at night
10 hours a day is plenty once you got things the way you want them - running the pump over the chlorine tabls uses and
activates chlorine

backwash more often than 3-4 weeks, whith my pool I can see what is coming out as waste and if it is brown i let it run til it clears up - if it is clear I just stop and do something else\

backwashing depends on what is going thru the system _ I do not believe I am suppose to leave a lot of crap in my sand filter to maek it work properly

  • the pool guys say 24-7 cause it make stheir life easier when everything is working and when it’s not they are amking money.

spend 10 minutes a day with the pool - you can think of somethig to do

give what you do an opportunity to work

don’t have water tests run, buy all kinds of chemicals and drive yourself nuts - use only that “Basic” test kit

Keep it simple - this is a hole full of wqater with a pump and filter

9

Get your chemicals from a warehouse if possible. The little pool supply stores can be good if you need service, but their markup on chemicals can be severe. I paid half price at a warehouse.

10

Philster, you win the stuffed bear.

I had zero Cyanuric acid. I’ve bumped that up and the pool has returned to normal.

Thanks for the replies everyone.