TDS Levels for my situation?

[ti_chris]

Hi,

I've recently switched from the all too common trichlor pucks to liquid chlorine coupled with liquid acid to keep my Cl & pH in line. I've been happy with the results thus far, whoever predictably, my TDS which has historically been very low has now been steadily climbing. Pool stores would of course have you refill the pool at 1500, but I'm wondering what level is actually safe for my pool. A bit of info about my pool:

The pool is a 24k gallons gunite pool and the only chemicals I throw in there are the 2 mentioned above. My main drain is an old Copper pipe, but all of the other returns are plastic (assuming ABS). I'm in Califiornia, which means that we ahe an arid cilmate and there's enough wind and trees that dirt inevitably does get into the pool. I'm currently pouring around 1/2Gallon of chlorine per day and roughly a quarter of that in acid. My TDS has risen relatively quickly in a few months (about 200 in 2 months).

My question here is what's safe and acceptable for my pool assuming that most of the TDS are from the chemicals I'm adding in the pool? I've read somewhere about salt ions not being great for Copper (particularly the ability to leech off of it if the conductivity is too high). Should I stick to a strict 1500 for TDS and refill like everyone else (probably once a year)?

I moved to liquid chlorine hoping that it would diminish my need to refill the pool every year, but at this rate, the TDS is rising fast enough that it seems I'll have to do it yearly anyways .

 

[mknauss]

TDS is meaningless. You must still be getting tests from a pool store.

Get your own proper test kit.

 

[Leebo]

To expand on Marty's comments, TFP prefers to ignore TDS as a whole and look closly at each variable that makes up TDS. A user could have VERY high Calcium levels but low salt levels and end up with a low TDS level. In this case the user can experience scaling and so forth on equipment or surfaces and see some issues. On the flip side a user may have low CH levels yet high Salt levels (salt water generator as an example) and end up with a very high TDS level. In this case it's possible the user will never see any issues.

In short, TDS is something that's not very helpful as there's simply too many moving parts. Instead lets look at each moving part individually and give assistance from there.

 

[ti_chris]

TDS is meaningless. You must still be getting tests from a pool store.

Get your own proper test kit.

I have a test kit that I run daily, but I'll use the pool store's test once a month or so since some of my tests are near useless with the home kits. Namely, I haven't found anything that measures the CH properly (ie: in a way I can discern the levels). The last things I tried were test strips and unless the numbers are crazy high, it hardly shows a signal.

To expand on Marty's comments, TFP prefers to ignore TDS as a whole and look closly at each variable that makes up TDS. A user could have VERY high Calcium levels but low salt levels and end up with a low TDS level. In this case the user can experience scaling and so forth on equipment or surfaces and see some issues. On the flip side a user may have low CH levels yet high Salt levels (salt water generator as an example) and end up with a very high TDS level. In this case it's possible the user will never see any issues.

In short, TDS is something that's not very helpful as there's simply too many moving parts. Instead lets look at each moving part individually and give assistance from there.

Yah that makes sense. I read the article and agree with the concept. I guess my question is really more around "Assuming that all of my chemicals are balanced as per TFP (which I follow) should I be worried about anything in my pool that may cause my coper pipes to get attacked over time due to the liquid chlorine adding salts to my pool"? The short answer seems to be 'yes' I should be worried since salt is corrosive to copper pipes. The follow-up question would then be how can I go about testing that and what levels would be problematic?

 

[Newdude]

The short answer seems to be 'yes' I should be worried since salt is corrosive to copper pipes. The follow-up question would then be how can I go about testing that and what levels would be problematic

Well for starters, With seawater at 35,000 ppm salt, It’s a much bigger concern. With a chlorine pool 500-1500 ppm or a ‘salt pool’ 3000-4000 it’s 90% +, less of a concern.

 

[Bperry]

I have a test kit that I run daily, but I'll use the pool store's test once a month or so since some of my tests are near useless with the home kits. Namely, I haven't found anything that measures the CH properly (ie: in a way I can discern the levels). The last things I tried were test strips and unless the numbers are crazy high, it hardly shows a signal.


Yah that makes sense. I read the article and agree with the concept. I guess my question is really more around "Assuming that all of my chemicals are balanced as per TFP (which I follow) should I be worried about anything in my pool that may cause my coper pipes to get attacked over time due to the liquid chlorine adding salts to my pool"? The short answer seems to be 'yes' I should be worried since salt is corrosive to copper pipes. The follow-up question would then be how can I go about testing that and what levels would be problematic?

the TF-100 or the Taylor k2006C measure CH just fine. The strips are pretty useless. Best advice would be to not use the pool store test at all and get one of the TFP recommended test kits above.

 

[ghall6292]

Once I acquired my own test kit (TF-100) all my pool chemistry got much simpler to understand and manage. I have no SWG nor any automation. For instance, I now know that if I didn't test my pool yesterday, I need to add 24 oz. of 7% liquid chlorine today (I know my LC is 7% because I learned from TFP how to test it with my TF-100.) But of course I do test it and discover I need to add 24 oz. of chlorine. How much are you willing to pay for this kind of peace of mind?

 

[ti_chris]

Well for starters, With seawater at 35,000 ppm salt, It’s a much bigger concern. With a chlorine pool 500-1500 ppm or a ‘salt pool’ 3000-4000 it’s 90% +, less of a concern.

Yah at sea-levels, I would expect the pipes to crumble pretty fast, but I still haven't seen any good literature about acceptable levels of sodium chloride vc copper pipes.

the TF-100 or the Taylor k2006C measure CH just fine. The strips are pretty useless. Best advice would be to not use the pool store test at all and get one of the TFP recommended test kits above.

Great. I'll get myself the components I'm missing from that kit. The test strips were absolute garbage.

Once I acquired my own test kit (TF-100) all my pool chemistry got much simpler to understand and manage. I have no SWG nor any automation. For instance, I now know that if I didn't test my pool yesterday, I need to add 24 oz. of 7% liquid chlorine today (I know my LC is 7% because I learned from TFP how to test it with my TF-100.) But of course I do test it and discover I need to add 24 oz. of chlorine. How much are you willing to pay for this kind of peace of mind?

I've recently installed Stenner pumps to make the process easier. I still test my pool daily to see if I need to add a little more than the pump adds, but on a hot summer day; I typically need to add 64oz of 10% to compensate for the 2PPM loss I tend to get per day. I could add the chlorine manually, but doing it this way makes it safe to add chemicals people are in the pool and I can also do it from the house with a little bit of automation. My main concern right now is the salt content and its effect on my copper pipes.

 

[BenB]

Hello San Jose!

Any increase in TDS (taking pool store results at face value though it is almost certainly inaccurate) is more likely just summer evaporation adding CH via the replacement fill water. Are you on SJW and if so do you know the source of your water (they publish a map with calcium ranges for each)?

Do you have a cover?
What's your CYA?

And for my own curiosity, how old is your pool such that you have copper pipes?

 

[Leebo]

Low pH is going to play a considerably more vital roll in messing with your copper lines than is salt. While I'm not sure the exact numbers that salt will start to ruin plumbing I do know that with a pH below 6.8 you're starting to damage stuff slowly. Do you have some test results so we can see if anything jumps out to us?