- Nov 21, 2011
- 21
- Pool Size
- 18000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
I could really use some help understanding the problem I'm having. I have been unable to solve this puzzle. I have a 18,000 gallon in ground pool and a connected 1000 gallon spa that was built in 2010. I use a SWG system to chlorinate. I live in Seattle and temperatures are around 40F in the winter and it takes the spa about an hour to come up to temp. I've been using it once to twice a week. The heater is only used to heat the spa, I use a geothermal heating system to heat the pool in the summer (the same system heats the house in the winter).
After about 10 years, I noticed black scales in the spa after heating the water. I assumed my heater element was corroding and replaced the spa heater with the same RayPak 406A 399 BTU cupro nickel propane heater last February. This did indeed solve the scaling problem for about 10 months and now it is back.
I noticed that my calcium hardness level was at 600. I had read that calcium oxalate can be reactive with copper while heated and cause black scaling. I drained roughly half the pool water and replaced it. Calcium hardness is now 280. I also flushed and descaled the heater following a video tutorial I found here on TFP (
). However, this also failed to solve or even improve the scaling problem.
My questions are what is the cause of scaling and is there anything I can do to solve this?
My most recent testing levels using Taylor K 2005 test kit
Ca Hardness 280
Total Chlorine 4
Free Chlorine 4
pH 7.8
Total Alkalinity 100
Cyanuric Acid 40
Salt 3600
I want to thank you for taking the time to read this and help me solve this riddle!
After about 10 years, I noticed black scales in the spa after heating the water. I assumed my heater element was corroding and replaced the spa heater with the same RayPak 406A 399 BTU cupro nickel propane heater last February. This did indeed solve the scaling problem for about 10 months and now it is back.
I noticed that my calcium hardness level was at 600. I had read that calcium oxalate can be reactive with copper while heated and cause black scaling. I drained roughly half the pool water and replaced it. Calcium hardness is now 280. I also flushed and descaled the heater following a video tutorial I found here on TFP (
My questions are what is the cause of scaling and is there anything I can do to solve this?
My most recent testing levels using Taylor K 2005 test kit
Ca Hardness 280
Total Chlorine 4
Free Chlorine 4
pH 7.8
Total Alkalinity 100
Cyanuric Acid 40
Salt 3600
I want to thank you for taking the time to read this and help me solve this riddle!