I think I want to go salt.

[estermer]

Here are my test results.

Free Chlorine 3.0
Total Chlorine 3.0
PH 7.6
TA 110
Calcium Hardness 270
CYA 30
Total Disolved Solids 650

[Poolsean]

Looks like a case of low cyanuric acid ??!!? Tri-chlor tabs being used and low cyanuric acid? Very Interesting!
Any chance your pool having an Automatic Water Level device and perhaps a leak somewhere?

If not, it's possible that your low cyanuric acid is allow the sun's uv rays to degradate the chlorine.
You can use a Salt Chlorine Generator, but as with very wise recommendations, you're better off upsizing the cell to the largest one you can afford. This should provide a higher chlorine output, longer warranty, and longer cell life.

[SJohnson]

If there's a leak or constant refilling, wouldn't his total dissolved solids be lower??, 650 seems a little high to me . . . I say bring your CYA up to at least 60 before you install the SWC. Triclor use with low CYA levels, hmmm . . . something's not right with this picture, I agree . . . All those numbers look exactly where you want them to be!!

You're not using Calcium Hypochlorite are you?? You did say, "I regularly dump about 1 pound of granules" . . . That would explain allot, but I didn't think you were supposed to use that with in-line feeders . . .

SJohnson

[estermer]

Well the water in the pool has only been in it for about 10 months. I have also backflushed my filter twice since then and had to drain off some after a heavy rain.

The granules I put in is Sodium Dichloro-s-triazinetraine dihydrate and I put it directly into the pool.

What is the optimum level for CYA for a bleach pool and for a Salt pool?

[SJohnson]

Is that the same as sodium dichloroisocyanuric acid?? Anyway, the accepted levels for a "bleach" pool are around 30-50 ppm. Where the Salt Cell manufacturers recommend 60-80 ppm, I believe. Again, some on this site keep their levels much higher, say 120 ppm, with very high levels of chlorine to offset the conversion of chlorine to chlorimide, or chlorine lock, where the chlorine no longer is actively disinfecting the pool water. PoolDoc(Ben) wrote somewhere that high levels of CYA could be considered a good thing, where it preserves your chlorine longer and prevents it from being burned off in the sun. This way you don't have to add chlorine as often . . . it had something to do with the chlorine's reaction time to bio-bugs in the water. The downside being that highly stabilized chlorine has a slower reaction time than chlorine with lower levels of stabilizer in the water. I think he said high stabilizer levels kept the chlorine in reserve and released it as needed, but the time it took to release the chlorine added to the chlorine's disinfection reaction time . . .Something like that, I remember the article or thread was a very interesting read, wish I could track it down, but it may have been lost when the board crashed . . .

Hope this is helping you, I think you just need to bump up your cya levels a little . . . the debate is ongoing about cya levels and where they should be, everyone seems to differ on that subject a little.

-SJohnson

[SJohnson]

Wait a minute . . . You said that you have an inline chlorinator and you add granules every few days? You put trichlor tabs in the feeder and are dumping dichlor granules in the pool directly? Is that right? CYA levels are usually very stable so minimal draining and backwashing will not lower it all that much. Hmmm. Did you test the CYA or did a pool store test it? That kind of Dichlor your using is 56% chlorine whereas Trichlor is 90%. 1 lb of Dichlor should raise your chlorine level about 3 ppm, in summer heat, direct sun, every 3-4 days, that doesn't sound all that unreasonable . . . you're gonna love the Salt Cell . . . I'll bet.

SJohnson

[Poolsean]

SJohnson, 650 ppm TDS is not too bad. Most tap water is really low, about 100 ppm. I would say that 10 months of tri-chlor and di-chlor, both of which adds salt and cyanuric acid to the pool, would have increased the cya level and salt level higher. The backwashing and rain water drain off, would account to a lower level, but a leak would certainly lower these levels much more than normal.
However, since there was no response about an automatic water fill line, or any suspicions of a leak, there probably isn't one. OK...so back to what is consuming your chlorine at a higher pace than normal. One should not need to have a tri-chlorine erosion feeder AND have to hand dose di-chlor.

Have you added anything other than chlorine and acid to your pool? Take that back, since tabs and di-chlor are both low on the pH scale, no need for acid, but perhaps some soda ash, to increase pH. Any algaecides, clarifiers, or additives? If so, these may be reacting with the chlorine added and just plain and simply, using up the chlorine.