I read where using borates can help you keep your TA lower than normally called for, so it made me wonder... When using borates, what are the ideal ranges for everything in a non-swcg pool? And is there a benefit to keeping TA lower?
Ideal chemistry using borates?
- Thread starter stebs
- Start date
I keep the TA where it keeps the pH stable. If the pH is constantly going too low, I raise the TA. If the pH is constantly going too high, I lower the TA. When the TA is right, the pH will stay right.
Getting more specific depends on several factors, such as water temperature, aeration, pool surface, chlorine source, other chemistry levels like calcium hardness and cyanuric acid levels etc.
Getting more specific depends on several factors, such as water temperature, aeration, pool surface, chlorine source, other chemistry levels like calcium hardness and cyanuric acid levels etc.
I dont know where you read that, but its not true as stated.
Borates are one of the recommended items to raise pH. A side effect of that is that may help stabilize pH. If maintained properly, TA will stabilize the pH on it's own. Borates should not be added with the intention of keeping a lower TA.
Borates are one of the recommended items to raise pH. A side effect of that is that may help stabilize pH. If maintained properly, TA will stabilize the pH on it's own. Borates should not be added with the intention of keeping a lower TA.
Well, this is true in an indirect sense. In spas, for example, if one were to try and maintain a lower TA level of say 50 ppm in order to reduce carbon dioxide outgassing, then one can still get fast pH rise and possibly get scaling in their spa because even 50 ppm TA doesn't completely stop the outgassing though it does cut down on the amount of acid needed. So the use of 50 ppm Borates is in fact used as an additional pH buffer that is not carbonate-based so does not contribute to carbon dioxide outgassing and hence pH rise. This additional pH buffering slows down the pH rise so it is true that the combination of a lower TA along with 50 ppm Borates is useful, most especially in spas.
Now for pools, pH rise from carbon dioxide is usually not as big of a problem as with spas because the amount of aeration is typically less and the pool depth is deeper (so outgassing rate slower relative to volume of water that affects pH change) and the water is typically cooler than in a spa so has slower outgassing rates. However, if the pool is a plaster one then you need to saturate the water with calcium carbonate so if you were to lower your TA to reduce carbon dioxide outgassing you'd need to compensate with a higher pH and/or CH target to keep things in balance to protect plaster surfaces. The use of 50 ppm Borates may help reduce the rate of pH rise, but it normally doesn't lower the amount of acid you need to add over time (you just add a larger individual amount less frequently) so it is the lower TA level that reduces the amount of acid over time.
We normally recommend the use of 50 ppm Borates in pools when there is a saltwater chlorine generator system because these pools tends to have more of a pH rise and also the borates significantly help to reduce calcium carbonate scaling in the generator cell (at the hydrogen gas generation plate) because the additional pH buffering cuts the pH rise at the plate roughly in half. Nevertheless, the use of borates is still optional in such pools.
The bottom line is that for your non-SWCG pool you would only use a lower than recommended TA level if you had a serious pH rise problem that was known to be due to carbon dioxide outgassing and in that situation you could use 50 ppm Borates along with the lower TA level, higher pH target, and higher CH if you've got a plaster pool surface. So if you had waterfalls, spillovers, fountains, or other sources of aeration that you simply could not live without, and if these were contributing to significant pH rise and acid usage (say, because you don't use a pool cover), then you could consider running your pool at a lower TA level with 50 ppm Borates. Most pools don't need this.
Now for pools, pH rise from carbon dioxide is usually not as big of a problem as with spas because the amount of aeration is typically less and the pool depth is deeper (so outgassing rate slower relative to volume of water that affects pH change) and the water is typically cooler than in a spa so has slower outgassing rates. However, if the pool is a plaster one then you need to saturate the water with calcium carbonate so if you were to lower your TA to reduce carbon dioxide outgassing you'd need to compensate with a higher pH and/or CH target to keep things in balance to protect plaster surfaces. The use of 50 ppm Borates may help reduce the rate of pH rise, but it normally doesn't lower the amount of acid you need to add over time (you just add a larger individual amount less frequently) so it is the lower TA level that reduces the amount of acid over time.
We normally recommend the use of 50 ppm Borates in pools when there is a saltwater chlorine generator system because these pools tends to have more of a pH rise and also the borates significantly help to reduce calcium carbonate scaling in the generator cell (at the hydrogen gas generation plate) because the additional pH buffering cuts the pH rise at the plate roughly in half. Nevertheless, the use of borates is still optional in such pools.
The bottom line is that for your non-SWCG pool you would only use a lower than recommended TA level if you had a serious pH rise problem that was known to be due to carbon dioxide outgassing and in that situation you could use 50 ppm Borates along with the lower TA level, higher pH target, and higher CH if you've got a plaster pool surface. So if you had waterfalls, spillovers, fountains, or other sources of aeration that you simply could not live without, and if these were contributing to significant pH rise and acid usage (say, because you don't use a pool cover), then you could consider running your pool at a lower TA level with 50 ppm Borates. Most pools don't need this.