Diamond Brite Numbers

[RJPassan]

First a huge thanks to everyone for this site and all the info, posts, etc. I've learned a lot since late last year after much frustration with several pool stores.
We had our 20 year old pool refinished with Diamond Brite on May 9. Coronado's Pool Plaster did a great job and I've worked hard to brush, test, and add chemicals to make the finish the best I can. The local SGM (Diamond Brite) rep had his own pool service business for 24 years so one would think he must be somewhat "in the know". Jason Lion says the Diamond Brite numbers are "old school" and one would be happier with the TFP numbers (saw that on an old post)

My questions are regarding the chem levels for the Diamond Brite finish:
1. pH ... Diamond Brite recommends 7.4-7.6, rep likes the lower end of that. 7.7-7.8 is listed as "ideal" on the TFP site for plaster. Your recommendations?

2. Total Alkalinity ... 80-120 recommended by D.B. I've been keeping it at around 80. Recommendations?

3. Calcium Hardness ... 200-400 (200 is ideal) per D.B. I'm at 250 now. Recommendations?

4. Free Chlorine ... 1-3 recommended by D.B. I told the rep that free chlorine depends on CYA level. That seemed to puzzle him a bit although he was familiar with CYA. I've been following the FC/CYA chart.

5. Cyanuric Acid ... 30-100 (40-60 is ideal) per D.B. I've been using Trichlor pucks so far (with a little Clorox here and there). Current CYA around 28. We get full sun so I want to bring it up a bit. Last year when I started with TFP my CYA was around 100 (from all of the Trichlor and Dichlor we had been using). I tested this year before pool was refinished and it was still around 100 (did not drop over the winter). I know the sun uses up the chlorine, but don't know if there is much difference in chlorine loss from a CYA of 30 to a CYA of say 60. Since I can't lower the CYA if it gets too high (without draining and replacing water ... which I don't want to do) any input on how high to get the CYA with our full sun a good part of the day is much appreciated!

Thanks much for the help and best wishes to one and all
Rick

 

[DaninFLA]

the pH range of 7.4-7.6 is good.

TA wouldn't worry about. if its too high, pH will raise faster, which requires you to add muriatic acid to lower. doing this over and over lowers your TA and your pH will stabilize. nothing to worry about.

CH - 250 is good. wouldn't add or subtract. it will go up thru evaporation and refills.

FC - yes, your DB guy isn't going to know anything about CYA/FC...go with the chart you are using, you are right.

if your CYA is under 30, it isn't accurate reading (lower limit is 30). add enough CYA to add 15ppm and then retest in a week, then adjust again as needed. for a freshwater pool, I would aim at CYA of 40 for where you are at. if you see high losses of FC, then bump it up again to 50. first goal is to get enough in there to be within the testing accuracy of the TF100 (minimum is 30).

you are in great shape on your numbers, just need a little bit of CYA and lower that pH slightly

 

[jblizzle]

1. Where do you see 7.7-7.8 as the recommended range? Anything in the 7s can be fine.

2. 80ppm is fine

3. Yeah, they do not "get" the FC/CYA relationship.

4. Up in PA, I would think 30-40ppm would be ok. If you get a LOT of sun, then a little higher might be better. If you feel you are having to add too much FC everyday, then bumping up the CYA can help.

 

[RJPassan]

Thanks for the replies. TFP Pool School lists pH numbers: 7.7-7.8 is ideal but anything 7.5-7.8 is doing fine
Rick