SWG Operation - Lessons Learned

[sw_stupid]

Just trying to keep this at the top so we can have a sticky. Has this already been saved as a sticky somewhere? I can't find it.

[sw_stupid]

So Pat, does this mean I need to maintain pH a LITTLE low (7.4 maybe) to make the SWC more effective? I am looking for a way to cut down how long the SWC generates (it's at 75% now). It sounds like a lower pH might help. I maintain 7.8 now.
Thanks,
Brad

[PatL34]

Brad,

7.8 pH is generally considered to be the high end where chlorine production by the cell is minimal. 7.4 would be ideal, and will help to reduce the loading on the cell, and the %age setting.

Depending on your system, if you can keep a fairly steady pH with muriatic acid, and the TA at 100 - 120 ppm, you should have more time for swimming.

Pat

PS. It is not yet a sticky and am waiting to hear from Ben regarding this.

[boscogabby]

Very helpful thread. I have an Aquarite SWCG and I have a PH of 7.4 and TA of 120 which I am able to maintain pretty consistently without adding acid. However I am reading alot in this thread about adding acid to maintain PH. Is this because most of these pools are plaster and not vinyl? I have an inground 12,000 gallon vinyl pool. Filter runs 12hrs a day and SWCG at 20%.

[PatL34]

I came across this anomaly in another thread in this forum I think and have not yet been able to find a reason for the steady pH in vinyl pools.

If you could post a complete analysis, and mention the chemicals you add on a regular basis, it might help to get a better insight. Also what you do when there is an upset through bather load, weather conditions, etc.

Pat

[cwstnsko]

The 1st thing you need to know to understand stability or lack therof is the chemistry of your make-up water. My make up water comes out of the tap above 7.8 and that's part of the reason I add acid on a regular basis. My pebble sheen is still less than 2 years old, so it may still be driving the PH up as well. I use about 2 gallons of acid a month in a 14,000 IG pool

[waterbear]

I have a fiberglass pool, my fill water has a pH of 7.2 and an TA of 110. My pool also has TA of 110. I have to add acid every 3 weeks to get my pH to 7.2. After 3 weeks it goes up to 7.6 or slightly higher and I add acid again. Run my cell at 5% output with 8 hours of run time to maintain 3ppm FC. Still a small price to pay for the sparkling water I always have with the SWG! I would think that the non reactive surface of fiberglass would be similar to vinyl but my pH does rise. Granted I have to add very little acid when I do. 1 gallon lasts close to 6 months!

[boscogabby]

I came across this anomaly in another thread in this forum I think and have not yet been able to find a reason for the steady pH in vinyl pools.

If you could post a complete analysis, and mention the chemicals you add on a regular basis, it might help to get a better insight. Also what you do when there is an upset through bather load, weather conditions, etc.

Pat

The only chemicals that I add are ph+ (sodium carbonate) and ph-(dry acid) from pool store. This is my first season with SWCG, used to use Baquaglop. I have not yet had an upset through a heavy bather load and I really do not do anything but vacuum after bad weather conditions, I just let the extra water evaporate. My latest test results are 5ppm FC - PH 7.4 - TA 120 - CYA between 60-70 and Calcium hardness at 250.

[PatL34]

Very helpful thread. I have an Aquarite SWCG and I have a PH of 7.4 and TA of 120 which I am able to maintain pretty consistently without adding acid. However I am reading alot in this thread about adding acid to maintain PH. Is this because most of these pools are plaster and not vinyl? I have an inground 12,000 gallon vinyl pool. Filter runs 12hrs a day and SWCG at 20%.

The only chemicals that I add are ph+ (sodium carbonate) and ph-(dry acid) from pool store. This is my first season with SWCG, used to use Baquaglop. I have not yet had an upset through a heavy bather load and I really do not do anything but vacuum after bad weather conditions, I just let the extra water evaporate. My latest test results are 5ppm FC - PH 7.4 - TA 120 - CYA between 60-70 and Calcium hardness at 250.

I see from your two posts above that you use ph+ and pH-. This tells me that you are using up salt for the process, and will eventually have to add some when the low salt alarm comes on. Dry acid is acid but in a different form, as it dissolves to form sodium sulphate and sulphuric acid. No problem in that but it tends to skew your argument regarding not having to add acid.

The total dissolved solids will increase in the pool accordingly, and may well be assisting the TA in acting as an extra buffer to minimize pH bounce. This is just a theory on my part. Someone with better chemistry than I, hopefully may enlighten us further.

Pat

[PatL34]

Have added some extra comments regarding bleach cost vs. SWCG cost in the "Pro" section of the original post (#1).

Pat