what is the recommended csi range
- Thread starter prasadkm0204
- Start date
- Apr 10, 2018
- 5,148
- Pool Size
- 18375
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45
The optimal range for a plaster pool is between -.30 and 0.0. Being on the slightly negative side will reduce the risk of scaling.
Thanks. Shouldn't PoolMath be updated to reflect the range. It doesn't mention about -0.3 to 0, until I posted this and read few other discussions on the forum.
- Mar 5, 2020
- 3,007
- Pool Size
- 66000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Astral Viron V35
The information shown in PoolMath changes according to your current CSI:
- below -0.6: Less than -0.6 suggests corrosion is likely for plaster, tile, stone, and pebble pools.
- between -0.6 and -0.3: You should avoid CSI of less than -0.3 for prolonged periods of time to avoid the potential of corrosion for plaster, tile, stone, and pebble pools.
- between -0.3 and +0.3: Congratulations, your CSI looks good.
- between +0.3 and +0.6: Greater than 0.3 suggests potential for scaling.
- above +0.6: Greater than 0.6 suggests scaling is likely.
Most important is to stay between -0.6 and +0.6.
Staying between -0.3 and +0.3 is the target, but there is no harm in dipping below -0.3 from time to time, e.g. while in the process of lowering TA.
The additional recommendation to keep CSI below 0 is for SWG-pools. The cathode plate in the SWG-cell is at increased risk for scaling due to the localised increased pH (and therefore higher CSI compared to the bulk water). Many SWGs can cope with this by switching polarity from time to time. Borates can also help, as the borate buffer-system is very effective in the higher pH-range.
The general TFP view is that CSI is of minor interest, "In general, most TFP members who follow the TFP Pool School – Recommended Levels page have no need to be concerned with CSI. Those parameters help to keep the CSI well balanced.", as explained in Pool School:
www.troublefreepool.com
If excessive scaling of the SWG-plates is an issue, then keeping CSI slightly negative can help. But a general hard and fast rule to keep CSI below 0 wouldn't be realistic for many living in desert climates, which often goes in combination with very hard water. Constantly warm water adds directly to the CSI, and high evaporation rates requiring frequent water additions with hard fill water lead to a constant CSI rise. Telling those to keep CSI negative is just not realistic. But for those it will be beneficial to monitor CSI and manage it, e.g. by keeping pH in a more limited range.
If SWG-cell scaling is no issue, then no need to micromanage. Scaling of the main vessel can occur with all pool surfaces, not just plaster. Keeping CSI below +0.3 is applicable to all pool surface types. Without an SWG, there is no general need for a further restriction to below zero. And even with an SWG it is not generally required. But it can help should excessive SWG-plate scaling be a problem.
- below -0.6: Less than -0.6 suggests corrosion is likely for plaster, tile, stone, and pebble pools.
- between -0.6 and -0.3: You should avoid CSI of less than -0.3 for prolonged periods of time to avoid the potential of corrosion for plaster, tile, stone, and pebble pools.
- between -0.3 and +0.3: Congratulations, your CSI looks good.
- between +0.3 and +0.6: Greater than 0.3 suggests potential for scaling.
- above +0.6: Greater than 0.6 suggests scaling is likely.
Most important is to stay between -0.6 and +0.6.
Staying between -0.3 and +0.3 is the target, but there is no harm in dipping below -0.3 from time to time, e.g. while in the process of lowering TA.
The additional recommendation to keep CSI below 0 is for SWG-pools. The cathode plate in the SWG-cell is at increased risk for scaling due to the localised increased pH (and therefore higher CSI compared to the bulk water). Many SWGs can cope with this by switching polarity from time to time. Borates can also help, as the borate buffer-system is very effective in the higher pH-range.
The general TFP view is that CSI is of minor interest, "In general, most TFP members who follow the TFP Pool School – Recommended Levels page have no need to be concerned with CSI. Those parameters help to keep the CSI well balanced.", as explained in Pool School:
Calcium Saturation Index (CSI)
How is CSI calculated? Very simple – use our PoolMath tool. To ensure long plaster life and save money, click here to learn more.
www.troublefreepool.com
If excessive scaling of the SWG-plates is an issue, then keeping CSI slightly negative can help. But a general hard and fast rule to keep CSI below 0 wouldn't be realistic for many living in desert climates, which often goes in combination with very hard water. Constantly warm water adds directly to the CSI, and high evaporation rates requiring frequent water additions with hard fill water lead to a constant CSI rise. Telling those to keep CSI negative is just not realistic. But for those it will be beneficial to monitor CSI and manage it, e.g. by keeping pH in a more limited range.
If SWG-cell scaling is no issue, then no need to micromanage. Scaling of the main vessel can occur with all pool surfaces, not just plaster. Keeping CSI below +0.3 is applicable to all pool surface types. Without an SWG, there is no general need for a further restriction to below zero. And even with an SWG it is not generally required. But it can help should excessive SWG-plate scaling be a problem.
