Chemical Balance questions

[Azsnook]

I have a pool with a SWG chlorination system and had a eak at one time. I believe I have slowed the leak significnatly, if not completely. My question is I appear to still be loosing salt, but at a slower rate. If I had been losing salt at the rate previously suggested, the calculated water loss would have been much higher than what I was actually experiencing. Am I having a pool chemistry issue where salt is being consumed through some other reaction?

My levels this morning were:
FC = 6.2
TC = 6.9
PH = 7.5
CH = 185
CYA = 59
Salt = 3,050 ppm

I use a LaMotte Color Q Pro 7 test kit for everything but salt and have a LaMotte handheld digital salt tester.

Thanks for any help.

[BigTallGuy]

Salt does not evaporate (nor is consumed) in a pool. You will have some salt loss when backwashing and through splash out, and certainly through a leak. How much Salt are you losing? How much water are you losing? I lose almost a half an inch a day in my 24 foot Round AG pool from evaporation, and I live in Mesa.

A good way to check for leaks is to take a 5 gallon plastic bucket and place it on the step in the shallow end of your pool so it is partially submerged, and fill it with pool water so the water in the bucket is even with the water level of the pool, and let it sit that way for 24 hours, then see if the water level in the bucket still matches the water level of the pool. If the pool level is lower than the bucket level, you still have a leak.

Does your Salt checker require calibration?

[Azsnook]

Thanks. I am also in Mesa. My salt levels have been declining around 20-40 ppm per day. I also run a water feature and have seen that aeration can deplete salt, but do not know if this is true. I was wondering why my CH struggles to get above 200, when new water flowing in is probably close to 400 ppm. I wondered if the salt was reacting with something the pebbletec or gunite needed since CH was a little low. My salt checker does require calibration. At the height of my leak adventure, I was losing about 1" per day and was losing 100 - 120 ppm per day on salt levels. I will re-try the bucket test.

[waterbear]

Thanks. I am also in Mesa. My salt levels have been declining around 20-40 ppm per day. I also run a water feature and have seen that aeration can deplete salt, but do not know if this is true.

Nope, salt cannot evaporate, only water can. You CAN lose salt from splashout in a water feature however.

[BigTallGuy]

Thanks. I am also in Mesa. My salt levels have been declining around 20-40 ppm per day. I also run a water feature and have seen that aeration can deplete salt, but do not know if this is true.

In our neck of the woods, water features will loose alot of water through evaporation, but as Waterbear says, you will not loose salt. You haven't mention what the source of your leak was nor what you did to fix it. How do you calibrate your Salt tester and how often?

[Azsnook]

I probably had multiple sources for leaks. The most significant was a spa light fxture - the PVC conduit most likely had an unglued joint along the way. Long story on all the attempted fixes, at the end of the day a product called Fix-A-Leak corrected the problem, where you circulate the material for 48 hours or so (with the DE filter removed) and keep it in suspension. The product finds the leak and will repair holes up to 1/8" diiameter. I also circulated the Fix-A-Leak throughout my pool system. The claim is it will fix both structural and plumbing issues. Suction side leaks are more difficult to treat with Fix-A-Leak because you have to reverse the flow and keep the PSI fairly low, so I did not do that.

My spa is 6.5 feet by 7 feet and was losing 10" of water in a 24 hour period, which is about 285 gallons per day, now it holds steady after the fix. My total water volume (pool, spa and water feature) is about 20,000 gallons. My salt loss calculations would equate to losing about 1,000 gallons per day, but I think my actual water total loss was around 600 - 700 gallons per day, with half coming from the spa light. I started another bucket test in my pool this morning.

I calibrate the salt tester with a known 3,000 ppm sample through a calibration routine built into the tester. I calibrate every couple of weeks.

In the last two weeks, I have gone from 3,800 ppm to just under 3,000 ppm, which would indicate I have lost over 4,200 gallons of water, or 300 gallons per day. When my leak(s) were at their worst, my autofill ran loudly and continuously, now its always a very low trickle.

[BigTallGuy]

My 24' round AG pool holds about 11,000 gallons, with an average water depth of 42 inches. If I loose approximately 1/2 inch per day to evaporation, that figures to be somewhere near 130 gallons a day as a comparison. With Your pool being approximately twice as big, 300 gallons/day may not be too far off. However, you will not see salt loss through evaporation. During your peak loss, you were double that amount so I'm glad to know you got it fixed.

What was the result of your first bucket test?

I don't have any experience with Salt Testers, but I can tell you that I get a different reading at just about every pool store in our area. Have you compared your unit against any pool stores?

[Azsnook]

Well, Ratz! The result of my bucket test this morning is about 100 gallons to evaporation and 200 gallons unaccounted for - so I still have a leak. The 200 gallons accounts for the 20-40 ppm of salt.... Fortunately, the leak is probably pressure side since I got similar results with and without the pumps on.

I have not compared my tester results to any pool store testing - have compared to test strips and have gotten ballpark similar results.

[BigTallGuy]

So, Exactly how much water evaporated out of the bucket?

[Azsnook]

I lost almost 3/8" to evaporation and have an approximate 500 square foot surface area. In the pool I lost another 1/2" to 5/8".