CH level and FC frequency

[pakrh8r]

My first question is regarding calcium hardness. I was having trouble last year (1st year with TF-100 kit) getting a consistent value from the CH test. I ended up getting a magnetic stirrer near the end of the season but never checked CH with it before I closed up the pool. I opened up the pool last weekend and tested the CH on Monday and yesterday, coming up with about 140 each time (using magnetic stirrer and stopped counting drops when color stopped changing). I know that the suggested levels are more guidelines than hard and fast rules, but a CH level of 140 is well below the 250 - 500 recommendation I've seen in a few places. Just to confirm that I was getting a fairly accurate result I decided to try to find the CH of the tap water here in Chicago. After some searching I found the last reported chem analysis on the city's website:http://www.cityofchicago.org/content/dam/city/depts/water/WaterQltyResultsNRpts/ccReports/cca13c.pdf. If I am reading this report correctly, at around line 15 it gives a reading of CH at ~140 depending on which site. My water comes from the Jardine plant. My question (finally ) is should I add calcium to my above ground vinyl pool? If so what level should I try to get it up to? How often should this level be tested?

My other question is: should I be testing my FC levels with the FAS-DPD drop test every day or just use the OTO test for daily testing? I'm not the biggest fan of matching the yellow colors on the OTO test and have been testing with the drop test every day. Am I just wasting testing supplies or do most of you test with the drop test daily?

Thanks.

 

[jblizzle]

Low CH does not matter in a vinyl pool. No need to add any.

Regarding FC: It is up to you. Many members use the OTO as a quick check every day and use the FAS-DPD once a week to confirm. Others use the FAS-DPD everyday to have a been FC and CC reading. As you get to know your pools chlorine needs and start to see consistent results, you may get more comfortable with just using the OTO test.

 

[pakrh8r]

Thanks for the quick reply. A follow up question to the CH level - does a high or low CH level affect my equipment (heater, pump, etc.)? Any concern with those and a CH of 140?

 

[jblizzle]

No a low CH is not a problem with the equipment. A high CYA (500+ppm) can cause problems in your pool in the form of calcium scaling ... a high pH and TA is usually also required for that to develop.

 

[pakrh8r]

Great, thanks for the help.