Can't keep chlorine in my pool

Here are my pool water values:

FC: 0.1 ppm
TC: 0.3 ppm
Comb C: 0.3 ppm
pH: 7.6
Hardness 370 ppm
Alk: 97 ppm
CA: 45 ppm
Copper: 0.27 ppm
Iron: Not run
Nitrate: 7 ppm

I added a stabalizer chlorine (96%) I think...about 2.5 lbs last night...no cholorine in the pool today

I just dumped a bunch from my EZ shock bucket into the pool...didn't even flippin measure it. Probably 2 -3 lbs.

When I do add shock it is clumping on the top of the water and I don't know why.

What do I need to do to get my pool back in shape. Is it in a chlorine lock and if so, how much more do I need to add? The stabilizer is a much higher percentage of CL and I have another 2.5 pounds left of that.

When we initially opened the pool I had no chlorine problems.

Thanks for your help.

Hello, and welcome to the forum!!

I'm assuming your CA level is actually your CYA--stabilizer--and if it's actually 45 ppm, you need to be keeping your chlorine at 3-6 ppm at all times in order to keep algae away. The fact that your CC is greater than your FC means that you definitely need to shock the pool. With a CYA of 45, that means reaching a chlorine level of 15 ppm and holding it there until you're no longer losing any chlorine overnight and your CC is zero. You can use plain, unscented bleach to do this, which is probably easiest, but if you use the "shock" that you have on hand (I'm assuming that is dichlor?) you really should pre-dissolve it in a bucket of water before putting it in the pool to keep it from clumping up.

There is no such thing as chlorine lock. From looking at your numbers, it looks like you probably have an algae bloom trying to happen, and it's consuming the chlorine as fast as you put it in, hence the need to shock the pool.

Well bleach is going to be the cheapest option at this point. How much do you think I should put in? My pool is a 29,000 gallon white plaster gunnite(sp) pool. I just checked the chlorine after having dumped 2.5 pounds of shock (not dichlor) in and it has basically almost disappeared again after only about 2 hours. I do have algacide in the pool that I put in weekly....I guess that stuff isn't working? My pool water looks so beautiful...just no chlorine....it is rather disappointing and very frustrating!

I just used The Pool Calculator and it is saying about 7 gallons of bleach...if that sounds reasonable, let me know...I'll add it tomorrow night and then see how the rest of the week goes. It is supposed to cool down a bit anyway so we can stay out of the pool for a while. 15 ppm....man that's a lot.

7 gallons should add about 14.5ppm of chlorine, so that would take you up to shock level. But, before you do this, let me run your copper level past Ben. Shocking a pool that has metals in it can sometimes cause staining, so sit tight until Ben comments on the copper level.

JG;

I'm guessing that's a dealer test? Those are awfully unreliable -- we see dealer test results that range from dead on, to 'not in the same ballpark', but until you have a K2006 yourself, we have no way of knowing which is which.

In particular metal test results seem almost random. However, showing up with Cu=0.27 ppm immediately raises the question, is it possible that you DO have copper in the pool?

The problem is that copper can stain by itself, if it's high enough, when you mix copper and chlorine stains and green hair become almost inevitable.

Here's what you need to do:

1. Get a cheap OTO/phenol red test kit, and test with that. The good thing about OTO is that, though it's not very accurate, it's very very reliable. If you have chlorine, OTO will show it. And if OTO says you have none, then you have none.

2. Add small doses of chlorine EACH evening: about 1 gallon of bleach, poured THROUGH the skimmer, in 4 parts should minimize risk. Make SURE (1,000% sure!!) you have removed ALL chemicals, tabs, pillls, etc from the skimmer BEFORE you add bleach.

3. If you have ANY trace of algae, see if you can find some polyquat locally, and use it (info => www.poolsolutions.com/polyquat.html) Otherwise, order it here:

Kem-Tek 60% polyquat @ Amazon

Polyquat will help filter any copper particles that form, and will not trigger stains OR make your pool foamy OR add copper. Be SURE to check the label before you buy locally, and be SURE you match the chemical name.

4. Tell us if you've used any copper containing chlorine (some voodoo blend tabs and granular have added copper -- it will be listed in ingredients), a pool heater, an ionizer, anything like EZ-Chlor or Simply Blue, or an algaecide containing copper.

5. Complete this Pool Chart Form:

Pool Chart Entry Form
Pool Chart Results

6. Order a K-2006 (test kit page linked in my sig)

7. Start using our Pool History Form (I've got to make it; links in the next post).

Pool History Entry Form
Pool History Results

The results I gave you are from the pool store. However, I do use the OTO test kit for pH and chlorine and it is pretty clear after I add the drops that I have no chlorine in the pool. The pH from the test kit is matching the pool store value. When the pool was opened, I was getting what I should get using the test kit.

Now for the Copper...I have a well and to fill the pool up after closing I use well water that has been properly Ph'd but it is not softened in any way. I have the classic toilet stains from my well water. I would think this is mostly iron though. I have had the pool for about 8 years or so and have always used well water. And I don't have any stains in the plaster either and I have dumped a lot of chlorine in my pool before especially before going on vacation...something like 8 to 10 pounds.

I assume the copper is a true reading...I had them check for phosphates as well and there were none.

I also don't see any algae at all. My pool looks crystal clear.

If you haven't added copper, I think it would be very unusual to see copper in well water with iron.

Iron can come out of the water VERY quickly.

I'm curious: if you've been running the pool for 8 years, why are you having trouble keeping chlorine in the pool THIS year?

Regardless:

1. Please fill out your forms; it makes it easier for us.
2. Test for chlorine demand by adding -- in the evening -- 2 gallons of plain 6% bleach per 10K gal of pool water (12 ppm FC).
3. Test your chlorine level 1 hour after dosing, and then again in the morning before 9 am.

If you've lost much chlorine, there's something in the water that has be chemically burned up (oxidized). The best way to do this is to add chlorine in the EVENING, so it doesn't get used up by sunlight.

4. Get a K-2006 testkit (or a HTH 6-way drops kit, if your Walmart has it). Both are Taylor kits; both give reasonably accurate stabilizer tests. IF step #3 doesn't show a significant chlorine demand, and IF you really have CYA=45, then you shouldn't be losing all that much chlorine during the day.

I have had this problem before. One time it was because I had phosphates in the pool. Another time I believe I didn't have enough cyanuric acid. But this time the CYA level was not in question at least that is what the data is showing and the phosphate test was negative. I did try to find the test kit in Target but they don't carry it...so I will try Walmart tomorrow.

I just put in 6 gallons of 6% plain bleach and will test in an hour like you suggested. I will leave pool pump on all night and test in the am.

You can check Walmart's site for the HTH 6-Way Test Kit and see if it's available locally.