Can't maintain the chlorine level

Chlorinating, maintaining the right chlorine levels,
chlorine problems. Dichlor, trichlor, cal hypo, bleach,
granules, chlorine pucks and chlorine sticks.
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Can't maintain the chlorine level

Postby Marian » Thu 28 Jun, 2007 18:59

I have been really frustrated at not being able to maintain any amount of chlorine in our pool this year, despite shocking the pool at twice the recommended dosage of Leslie's Chlorbrite and Power Powder Plus. We have used a Nature2 filter for several years, but we've begun to have a light staining on the bottom (resistant to chlorine, scrubbing and metal out products), so I decided to forego the Nature2 this summer when I read that it can sometimes cause stains on plaster pools. Before we got the Nature2 we always put a few chlorine sticks in the skimmer, and apart from weekly shocking, this was how we introduced chlorine into the pool. The staff at Leslie's told me not to use chlorine in the skimmers, however, because of potential corrosion of metal parts in the pump, so the only recourse we have is to float those ineffective chlorine dispensers around the pool. The other day I added 5 bags of Chlorbrite to our 30,000 gallon IG gunnite pool in the evening, and when I checked the water in the morning, the chlorine level was zero. At Leslie's recommendation, we tried an additional 4 lbs of Power Powder Plus, and it did bring the level up to 3, but it very quickly diminished again. The chemistry is Cl - 0, pH - 7.8, TA - 110, CYA - 20 (I added an additional pound of stabilizer, but since we usually use chlorine with stabilizer, I was concerned about adding too much CYA - ?). How do most people without chlorinators maintain the chlorine level in their pools?

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Postby dynamictiger » Fri 29 Jun, 2007 17:59

Technically Leslies are correct the chlorine in the sticks corrodes the pump seal.

However in practical terms as you have found out there probably is no other practical way to get the chlorine sticks dissolving fast enough without a dedicated feeder.

I would suggest you use the chlorine in skimmer as you have previously and when you can get a chlorine feeder cut in post filter and heater. Once this is done the concentrated chlorine is not in a position to damage the pump.

chem geek
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Postby chem geek » Fri 29 Jun, 2007 19:12

Two things. First, if you keep the pump running, then the acidic Trichlor should not harm the pump since it dissolves so slowly. It is more of a problem when the pump turns off and it continues to dissolve so that locally it is highly acidic in the skimmer and can damage plaster outside the skimmer. Then turning on the pump causes this blast of highly acidic water to flow through the system which MAY cause some damage.

The other alternative is to use specialized sticks of Trichlor that are designed for the skimmer. In theory, these do not dissolve when there is no water flow so do not build up in acidity, but I have never tested this myself. As was already stated in the previous posts, using Trichlor will build up your CYA level. For every 1 ppm FC introduced by Trichlor, you also get 0.6 ppm CYA.

The second item I wanted to bring up was that people who do not use stabilized chlorine add it regularly, even daily. Bleach or chlorinating liquid is typically added every day as is Cal-Hypo if that is used instead. If the pool has a cover, then you only have to add chlorine 2-3 times per week (I add chlorinating liquid twice a week in my pool that has an opaque electric safety cover).

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