New Plaster - Capitan's Log Day 20

[stinsontx]

Ok, I have started sailing towards the TFP goals in the new plaster remodel. Any thoughts on goals over the next 10 days or so? I took the alkalinity down over the past couple days to 80 (from 110) and getting to target FC (we are there essentially).

I guess my question is the CSI is -0.8 today with these results, which would be slightly corrosive. I guess at CY30 the carbonate alkalinity is 50. Hold here for a few days and let the PH aerate up? What sayith the TFP gods?

19K Gal white plaster, north Houston
======================
AIR TEMP: 28
WATER TEMP: 52
FC 4.8
CC <0.1
TC 4.9
PH 7.2
TA 80 (adjusted 12 hours ago, muriatic acid 128 oz)
CYA 30ish
CH 220

 

[Oly]

I would not tolerate a CSI of -0.8 in a plaster pool. Cold water temps are not helping your situation. Consider raising your CH slowly. Do you have high CH and TA in your fill water?

 

[stinsontx]

Oly: The fill water samples produce a TA of 150 and a CH of 50. There is no automatic fill valve on the pool, only manual valve.

 

[Oly]

I too have high TA fill water so anticipate dealing with that this summer unless you typically get rain to offset evaporation. Topping off manually can be an asset as it is a reminder to test TA with frequent additions.
With your CH fill water at 50ppm you will not be dealing with rapid CH accumulation over time so it is safe to raise your CH and avoid etching your new plaster surface with a low CSI. Play with your test numbers in Pool Math and observe how water temps affect CSI and also determine where you should be with CH ppm to protect your plaster.

 

[ajw22]

I would not tolerate a CSI of -0.8 in a plaster pool. Cold water temps are not helping your situation. Consider raising your CH slowly. Do you have high CH and TA in your fill water?

All he has to do is run the pH around 7.8 this time of year and CSI will be around -0.22.

Much easier then fooling with CH adjustments.

 

[stinsontx]

Thank you all for the input. The CH is climbing about 1PPM per day (plaster curing), I was 200 at start and now reliably testing at 220. The PH is low on the alkalinity adjustment, so I may just hold here for a bit and see how the PH recovers with regular aeration and running. I was easily achieving PH of 7.6-7.8 prior to the alkalinity adjustment.

 

[ajw22]

Thank you all for the input. The CH is climbing about 1PPM per day (plaster curing), I was 200 at start and now reliably testing at 220. The PH is low on the alkalinity adjustment, so I may just hold here for a bit and see how the PH recovers with regular aeration and running. I was easily achieving PH of 7.6-7.8 prior to the alkalinity adjustment.

Then your CSI will be ok. It was not clear what you usually run your pH at.

 

[Oly]

Your CH is rising in your low CSI pool water because it is leaching out of your new plaster.
Your TA and pH will rise as you add fill water but that be may not happen for some time.
My opinion is to keep a close eye on your water chemistry, your CSI and research the ideal CH levels for a plaster pool based on your starting CH of 200 ppm.