Chemical Troubles

[rh455]

I have a 22,500 gal gunite pool that is about 8 mos old. Pentair Intellichlor salt chlorinator. I have only added about 10# of salt since Dec. About 2 wks ago, I found a dead rabbit in the skimmer. I dumped 10# of shock and waited 2 days. Water looked great. A few days later, it started to "go green" again. I shocked again 5#. Within a week, I noticed that it was "going green" again. Back to the pool store with another sample. She said chlorine was way low and found the following: Iron,Copper,Allkalinity,hardness, all good. pH was high, so add 3pts of muratic acid. Shock needed again 4#. She also said my phosphate level was way high which could be eating up my chlorine. She said to shock it first, then add a bottle of phosphate remover and said to circulate for 48hrs. Then wash the filters out. I told her I hadn't added salt in a long time. I was never given a course on water maintenance, so I don't know how to tell if it's low on salt other than looking at the lights on the chlorinator unit, which are almost always green. I did add about 20# of salt to the skimmer yesterday, hoping to get me thru the weekend before I dump all these chemicals in the pool. This morning, the water looks much better, but if my phosphates are too high, it won't last, according to her. How often do I need to add salt!

[ps558]

I have a 22,500 gal gunite pool that is about 8 mos old. Pentair Intellichlor salt chlorinator. I have only added about 10# of salt since Dec. About 2 wks ago, I found a dead rabbit in the skimmer. I dumped 10# of shock and waited 2 days. Water looked great. A few days later, it started to "go green" again. I shocked again 5#. Within a week, I noticed that it was "going green" again. Back to the pool store with another sample. She said chlorine was way low and found the following: Iron,Copper,Allkalinity,hardness, all good. pH was high, so add 3pts of muratic acid. Shock needed again 4#. She also said my phosphate level was way high which could be eating up my chlorine. She said to shock it first, then add a bottle of phosphate remover and said to circulate for 48hrs. Then wash the filters out. I told her I hadn't added salt in a long time. I was never given a course on water maintenance, so I don't know how to tell if it's low on salt other than looking at the lights on the chlorinator unit, which are almost always green. I did add about 20# of salt to the skimmer yesterday, hoping to get me thru the weekend before I dump all these chemicals in the pool. This morning, the water looks much better, but if my phosphates are too high, it won't last, according to her. How often do I need to add salt!

First off get a tester for salt like this one

http://yhst-68516734483149.stores.yahoo.ne...alt-tester.html, yes it pricey but way better then test strips. You need to add salt when the level drops by going by what Pentair says the level should be for there machine. Low or high salt readings are hard on the generator to keep working properly.

Second always add salt directly to the pool not the skimmer and brush the pool after application. Try not to use water softener salt not pure enough but will work. They do make pool salt.

Do not shock the pool then add Phosphate remover, it is a waste of shock. Remove the Phosphates first by what the bottle says. Phosphates love to eat chlorine. Most require 24 hours then clean the filter and then start to add chlorine.

[PaulR]

There's a lot of good information in Pool School.

I would not expect salt levels to drop unless you dump and replace water. Between the test strips and the Intellichlor readout you should be fine.

I've never noticed phosphates being a problem as long as there's adequate chlorine. It's algae (and sunlight) that use up the chlorine, not phosphates.

You need to be monitoring your chlorine and pH yourself, not relying on the pool store.

Powdered shock might not be the best stuff to use. Calcium Hypochlorite will jack up your hardness and might contribute to scaling. Dichlor will jack up your stabilizer (cyanuric acid, CYA) and while a SWG can tolerate high CYA, there is a limit. I would (and do) use liquid chlorine, which is basically just double-strength bleach. You need to haul around the jugs but it adds NOTHING to your pool except chlorine and a little salt.

--paulr

[rh455]

She told me that everything was good but no clue why the chlorine was about 0. I've never had a crash course on using the test strips. Guess I'd better find out. Everything was fine but the phosphate level was high.

[imnay]

Removed

[chem geek]

I agree that sunlight eats chlorine but I have never bothered with testing for phosphates in over 22 years of great pool water but I'm the same with CYA - never tested for it specifically, never had a problem - maybe I'm too dumb to know better BUT I've never had a problem with having clean and clear water.

imnay, in this post of yours, you made it sound like you get cloudiness around every 4-6 weeks, depending on the number of people who have used the pool, and you use chlorinating liquid to shock the pool to get it clear again. In this post you say that your water has gotten cloudy "a few times" in spite of proper chemical balance (of the things you are measuring -- you aren't checking CYA). Yet above you say you "never had a problem with having clean and clear water". So which is it?

I don't know why you are resisting wanting to understand how the higher CYA level in your pool requires you to use an algaecide to prevent algae growth rather than having chlorine alone take care of that and that cloudiness occurs from the chlorine taking too long to oxidize organics because the CYA level is probably very high therefore requiring you to shock with chlorinating liquid periodically. It's fine if you want to continue with this approach, but please don't try and generalize it for everyone else's pool, especially those with plaster or fiberglass pools that have a much higher risk of staining if they use copper-based algaecide and for plaster pools that really do need to check the CH level as well as TA and CYA to ensure they don't pit/dissolve their plaster (calcium carbonate).

Richard