SWG Operation - Lessons Learned

[salinda]

Can you tell me what drop-type salt test I should use? I have been using the strips that you put in a small vial of water and wait a few minutes to take a reading.

Also, regarding the potential damage to tile/coping etc., I have found only the opposite. I have a Calcium reading on the high side (520 ppm). My overflow from my spa always had a lot of scale. Since the swg has been in operation, the scale has actually been disappearing. Maybe I am just more aware of ph and adding muriatic acid more often.

I do use A LOT of acid--at least 1/2 gallon/week with a 37,000 gallon pool.

[PatL34]

Can you tell me what drop-type salt test I should use? I have been using the strips that you put in a small vial of water and wait a few minutes to take a reading.

Also, regarding the potential damage to tile/coping etc., I have found only the opposite. I have a Calcium reading on the high side (520 ppm). My overflow from my spa always had a lot of scale. Since the swg has been in operation, the scale has actually been disappearing. Maybe I am just more aware of ph and adding muriatic acid more often.

I do use A LOT of acid--at least 1/2 gallon/week with a 37,000 gallon pool.

The salt water test kit is from Taylor, (Item # K-1766) which you can order from your local pool store. I don't think Taylor likes to sell to the public direct. Test your salt level at least once a week while removing the scale and then once a month when your pool chemistry is balanced. Use the salt test strips only as a rough guide.

A calcium reading of 520 ppm is definitely on the high side, so keeping the pH down to between 7.2 to 7.6 will definitely help. You will be using a lot of acid during this time. 300 ppm CH is your goal. The TA should be checked as well, and if above 150 ppm, I would start aerating to bring it down using a low pH down to 120 ppm. Hopefully your scale should disappear even faster.

Check your cell once a month too.

Hope this helps.

Pat

[salinda]

Pat, I have very little scaling now--less since the swg was installed (not what I expected, but it's great!). My TA is only 90 according to the PS233. My system is well-balanced except for the Ca level and that is the same as last fall when I closed. The cell on my Clearwater is clear so I visibly check it often and I did do a muriatic acid soak on it at the beginning of this spring. Why would the salt level change "while removing scale?" I had to adjust my salt level this spring because we got soaked this winter in California and my water was very diluted, but now we won't see rain until next fall so the salt level should be fixed.

Doesn't the salt water test use silver, which is expensive? That's probably why they don't have too many in stock.

[PatL34]

Pat, I have very little scaling now--less since the swg was installed (not what I expected, but it's great!). My TA is only 90 according to the PS233. My system is well-balanced except for the Ca level and that is the same as last fall when I closed. The cell on my Clearwater is clear so I visibly check it often and I did do a muriatic acid soak on it at the beginning of this spring. Why would the salt level change "while removing scale?" I had to adjust my salt level this spring because we got soaked this winter in California and my water was very diluted, but now we won't see rain until next fall so the salt level should be fixed.

Doesn't the salt water test use silver, which is expensive? That's probably why they don't have too many in stock.

You might have had some scale on the salt sensor which is now clearing up.
You should be able to get the salt water test kit easily. The chemical used is silver nitrate. This reacts with potassium dichromate indicator to give the red color of potassium nitrate.

The reason they don't have too many in stock, is that the test kit at $25, lasts a LOT longer than the test strips at about $8.00, a third of the price. They would rather you buy test strips.

Hope this helps.

Pat

[PoolDoc]

You might have had some scale on the salt sensor which is now clearing up.
You should be able to get the salt water test kit easily. The chemical used is silver nitrate. This reacts with potassium dichromate indicator to give the red color of potassium nitrate.

The reason they don't have too many in stock, is that the test kit lasts a LOT longer than the test strips at about a third the price, about $8.00.
Pat

Hi Pat,

It looks like you've created a thread worth making a 'sticky', but it's a bit cluttered with followup OT items. If you would, post a copy again, and then PM me when you have done. I'll add a 'threatening' follow-on , asking people who know (including Sean & Mark) to offer corrections. Once corrected (something I can't do, never having had a SWG), I'll 'sticky' it.

Oh, and about the K-1766 -- were you really able to get one for $8? It currently lists for $20.75, and I thought I was offering a real deal on the PS234S. But, if you can get one for $8, it's not a deal. AgNO3 prices *are* way up, so it's possible that the older price was much lower -- I haven't looked through old Taylor price lists. And, a very quick 'Google' for K-1766 showed prices between $24 and $35.

Ben

[PatL34]

Hi Pat,

It looks like you've created a thread worth making a 'sticky', but it's a bit cluttered with followup OT items. If you would, post a copy again, and then PM me when you have done. I'll add a 'threatening' follow-on , asking people who know (including Sean & Mark) to offer corrections. Once corrected (something I can't do, never having had a SWG), I'll 'sticky' it.

Oh, and about the K-1766 -- were you really able to get one for $8? It currently lists for $20.75, and I thought I was offering a real deal on the PS234S. But, if you can get one for $8, it's not a deal. AgNO3 prices *are* way up, so it's possible that the older price was much lower -- I haven't looked through old Taylor price lists. And, a very quick 'Google' for K-1766 showed prices between $24 and $35.

Ben

Ben,

Thanks for your support. I will "clean it up" so to speak and resubmit it. I was trying to make it as generic as possible.

Regarding the K-1766 testkit, it is the test strips that I meant were at $8. My apologies for the confusion, and I will edit that post to make it clearer. My kit cost $23 over a year ago.

Thanks again.

Pat

[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%.