What do I need to adjust? Low CSI.

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mrweber

mrweber

0
Jun 7, 2015
32
Norco, CA
Hello, using PoolMath calculator, it says my CSI is -0.8 and that anything over -0.6 means there is a problem.

My FC is high as I didn't adjust the output levels on my SWG when the weather got cooler and I have less direct sun on the pool. I am bringing that down by running output at 1%. CYA was also low, I added enough stabilizer to bring that up to ~70 yesterday which is the reason my pH is at 7.3 when I normally have it at 7.5. CH is the only thing that looks out of recommended levels, should I bring that up to ~350 range? I get some calcium buildup on my west facing wall where the spa overflow is, but everywhere else is fine.

Should I make any changes other than CH?

Current levels (using TF-100):
FC - 10.5
pH - 7.3
TA - 60
CH - 275
CYA - 60
Salt - 3300

Thanks,
Matt
 
If you look at the Recommended Levels for a plaster SWCG pool you'll see that your pH and CH are both low. You say you normally have the pH at 7.5 but usually in an SWCG pool the pH will tend to rise and it will do so faster when the pH is lower which is why we normally recommend 7.6 to 7.8. If you want to keep your pH at 7.5 and don't find yourself adding too much acid to maintain it there, then you can compensate by going to the high side of the CH recommended range.
 
mrweber said:
Hello, using PoolMath calculator, it says my CSI is -0.8 and that anything over -0.6 means there is a problem.

My FC is high as I didn't adjust the output levels on my SWG when the weather got cooler and I have less direct sun on the pool. I am bringing that down by running output at 1%. CYA was also low, I added enough stabilizer to bring that up to ~70 yesterday which is the reason my pH is at 7.3 when I normally have it at 7.5. CH is the only thing that looks out of recommended levels, should I bring that up to ~350 range? I get some calcium buildup on my west facing wall where the spa overflow is, but everywhere else is fine.

Should I make any changes other than CH?

Current levels (using TF-100):
FC - 10.5
pH - 7.3
TA - 60
CH - 275
CYA - 60
Salt - 3300

Thanks,
Matt
Click to expand...

What a coincidence as those are my same chem levels, right down to the high FC, no doubt due to my running my SWG for 24 hrs straight after having added all the salt (just got to the 30 day post new/ replaster phase). I had the SWG set to 50% and it still ended up with high FC (11.5). I'll just leave the SWG setting to 0% until my FC levels get back down.

Anyways, am taking steps to up my CH. I never thought I'd have that low of a CH level given how hard the water is here in San Diego, via the Colorado river as the source. Bought some Hardness Increaser and broadcast about a pound and a half and will recheck in a couple of days to see if my CH gets to my target. If I'm not mistaken, that will raise my TA. I'll want to get it back to 60 as I seem to be getting better PH creep control with that level (dual spillway + SWG led me to recently install an acid injection).
 
mrweber said:
Hello, using PoolMath calculator, it says my CSI is -0.8 and that anything over -0.6 means there is a problem.

My FC is high as I didn't adjust the output levels on my SWG when the weather got cooler and I have less direct sun on the pool. I am bringing that down by running output at 1%. CYA was also low, I added enough stabilizer to bring that up to ~70 yesterday which is the reason my pH is at 7.3 when I normally have it at 7.5. CH is the only thing that looks out of recommended levels, should I bring that up to ~350 range? I get some calcium buildup on my west facing wall where the spa overflow is, but everywhere else is fine.

Should I make any changes other than CH?

Current levels (using TF-100):
FC - 10.5
pH - 7.3
TA - 60
CH - 275
CYA - 60
Salt - 3300

Thanks,
Matt
Click to expand...

You are not far from me (Riverside) so I can offer up some advice. Due to the lack of rainfall that we receive here (unless El Nino pans out), do not add any calcium. Please educate yourself on the Calcite Saturation Index (CSI) and see how each parameter effects the aggressiveness of your pool's water in relation to the plaster surface. What you will find is that if you keep your pH and TA on the high side (to compensate for the low CH) you will maintain an environment conducive to longevity for your plaster.

Your CH will be continually rising by additions from fill water so it would be better to adjust for the lack of calcium now (with pH and bicarbonate) to make up for the excess you will more than likely experience in the future.

Your numbers look good, just let your pH rise (closer to 7.8). Raising your TA would help the low CSI value but would mean much more frequent acid additions due to C02 out-gassing...a choice you'll have to educate yourself on and make the ultimate decision.
 
Jaimslaw said:
What a coincidence as those are my same chem levels, right down to the high FC, no doubt due to my running my SWG for 24 hrs straight after having added all the salt (just got to the 30 day post new/ replaster phase). I had the SWG set to 50% and it still ended up with high FC (11.5). I'll just leave the SWG setting to 0% until my FC levels get back down.

Anyways, am taking steps to up my CH. I never thought I'd have that low of a CH level given how hard the water is here in San Diego, via the Colorado river as the source. Bought some Hardness Increaser and broadcast about a pound and a half and will recheck in a couple of days to see if my CH gets to my target. If I'm not mistaken, that will raise my TA. I'll want to get it back to 60 as I seem to be getting better PH creep control with that level (dual spillway + SWG led me to recently install an acid injection).
Click to expand...

Calcium effects the CSI, but does not impact the TA specifically. You are in the same boat as MrWeber and I, where we lack significant enough rainfall to compensate for the calcium content in our fill water. Adding calcium now will only mean draining water sooner (due to high calcium levels). Target a higher pH and TA (TEMPORARILY) until the CH reaches a level conducive to a balanced CSI (0 to - 0.2 for SWG pools) and then adjust other parameters accordingly. If you don't already know, pH has the greatest effect on CSI, and TA is second. The CH level has a surprisingly small impact (on CSI) until CH levels get very far from the TFP Recommended levels.
 
bdavis466 said:
Target a higher pH and TA (TEMPORARILY) until the CH reaches a level conducive to a balanced CSI (0 to - 0.2 for SWG pools) and then adjust other parameters accordingly. If you don't already know, pH has the greatest effect on CSI, and TA is second. The CH level has a surprisingly small impact (on CSI) until CH levels get very far from the TFP Recommended levels.
Click to expand...


This is good info to know, referring to what most affects the CSI numbers - I was playing around with the pool match caluclator with various combinations to get ideal CSI numbers and started to suspect TA and PH were the strongest influences on CSI numbers.

But it just seems a little harder to get tot hat ideal for SWG of between 0 to -0.2, though try I will.

I also suspect I am not reading my Taylor PH test colors accurately - that is, I may be keeping PH a tad lower than I should by interpreting the more peach PH color as the optimal 7.6- 7.8 level when I think theat 7.6-7.8 color needs to move more toward the pink, higher PH color - (the test kit not really having a peach color on its color scale to compare to).
 
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