Day 5, pool company arrived...

[texasAUtiger]

CSI is "Calcite Saturation Index". It tells you how saturated the water is with calcite, which in turn, lets you know if it can hold anymore.

When CSI is negative, it means the water has the potential to absorb more calcite, and will do so by pulling it from sources which have calcium (ie: your plaster).

When CSI is positive, it means the water is oversaturated with calcite, and has the potential to begin depositing it on surfaces in contact with the water.

Because your calcium is so low, you're hitting negative CSI with a relatively small pH drop. I agree with Pat, and you should raise the CH up, so you can maintain a very slightly positive CSI (while the plaster is curing) with normal range pH. Once the plaster is cured and established, it's best to maintain a slightly negative CSI, to avoid scaling problems.

The plaster manufacturer will have a required CH range, especially during curing, for the warranty as well, and it's most definitely above 50ppm for the minimum.

what would be a reasonable CH ppm for now? 100? 200?

It’s frustrating that I’ve been given zero guidance from my PB and I don’t even know the name of the manufacturer of my pebble/plaster other than “Peerless Pebble” and I can’t find anything on them.

 

[Texas Splash]

what would be a reasonable CH ppm for now? 100? 200?

TFP minimum is 250.

 

[texasAUtiger]

TFP minimum is 250.

ok but that is twice what some pebble manufacturers I’ve found recommended for plaster less than 28 days old.

 

[Texas Splash]

ok but that is twice what some pebble manufacturers I’ve found recommended for plaster less than 28 days old.

Please speak to your builder to confirm, but for all plaster-based products that is the TFP minimum recommendation. As noted by Stoop earlier, we want to make sure the water doesn't try to erode any plaster-related product from your pool.

 

[Stoopalini]

When I started my pool up, I took the pool builder's requirements, and compared them to both TFP and my plaster manufacture's targets, to derive my own targets. I did this to stay as close as possible to TFP guidelines, without risking the PB or the plaster mfg being able to blame any issues on the chemistry.

The far right column is what I used for my targets during the 1st 30 days, until I added salt and turned on the SWCG.

I planned all of this out, before the pool was filled, and ran it by my PB's construction manager, so they knew what I was planning to do. I didn't want any reason for the PB to deny fixing any issue which may have arisen.

Notice PebbleTek's pH requirement is much lower than bot the TFP and the PB's requirements. This is for the 1st 30 days only though.

 

[johngault007]

Please speak to your builder to confirm, but for all plaster-based products that is the TFP minimum recommendation. As noted by Stoop earlier, we want to make sure the water doesn't try to erode any plaster-related product from your pool.

I was also under the impression that calcium additions were not recommended for the first 30 days of new plaster. If that is not the case, it seems that my CH has hit a plateau from the new plaster after the first week of curing. Is it safe to bring the level up within the TFP recommendations now?

 

[Texas Splash]

I was also under the impression that calcium additions were not recommended for the first 30 days of new plaster.

TFP recommended start-up guide mentions no elevated FC level (SLAM/shock) for first 30 days. While your CH could fluctuate a bit while brushing-off calcium dust from pool surfaces, you don't want the CH too low. I would contact your builder to confirm, but in your case it appears appropriate to balance your CH as required. If nothing else, ensure you are at the TFP minimum of 250.

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