new pool owner with questions on high CH

[yuyiwen]

I am new pool owner in Fremont, CA with some questions. I have a 16000 gallon, plaster, in ground pool with SWG and solar heat.

Test results first:
FC=4
Tc=4
pH=7.7
TA=180
CH=1000
CYA=200

Do I have to replace most of my water to lower CH? If so, do I need to hire a pro or it's a DIY job? It's pretty dry in bay area, do I need to worry about pool popping if I drain most of the water?

Thanks!

 

[Richard320]

Welcome!

It sort of depends where in Fremont you are. If you're near the bay, water level might be close. http://www.water.ca.gov/waterdatalibrary/index.cfm has a map (really slow to load) that has well data. See what it's like around you. If it's lower than your pool is deep, have at it.

Also note, you're going to need to replace more like 75% of the water to reduce the CYA level to something manageable. Which, sadly, will not show a 75% reduction in CH, because your tap water is probably in the 200 range.

Rent or buy a submersible pump. The rental pump will go a lot faster than any reasonably priced pump you might buy.

 

[yuyiwen]

Thanks for pointing me to the map. I could not find well location close to my house. I will check with local pool service shops for advise of ground water level. The deep end of the pool is about 6'. I read there might be a hydrostatic valve in the main drain to relieve ground water pressure. Can this valve be opened while the pool is still filled with water?

I have some circular stains at the bottom of the pool, I've attached a picture. They are dark/black in color, could they be caused by dead leaves? Also, some stone blocks at the rim of pool are deteriorating with small pieces/powers dropping into the pool. Is this the main reason that I have a high CH level in the pool? Is there any way to seal these stones so it does not break off easily?

 

[Richard320]

The only question I can help you with is the high Calcium. Test your fill water. I'll bet it's real high in CH. Although if you have white crust on your showerhead and the coffeemaker clogs up, you can save the reagent.

 

[duraleigh]

All reliable CYA tests only reach to 100 ppm How did you get a result of 200 ppm?

 

[yuyiwen]

I got the test results from Leslie Pools. They used test strips. I've also tested out my tap water using Leslie's test strip, CH seems to be between 100 and 200 and pH is a little above 8.

I cleaned cartridge filter and salt cell couple weeks ago. The salt cell was scaled pretty badly, I acid washed it twice to get it clean. Now I am wondering what the high CH pool water does to the solar heating tubes on my roof...

 

[duraleigh]

Take leslies C test strip results at face value....they are worth what you paid for them.

A CYA test result of 200 I would consider completely unreliable. It's a fairly subjective test with a bit of a learning curve, but the Taylor CYA test using R-0013 reagent remains the truly best CYA test on the market today.

both the CH and CYA test by Taylor (or TFTestkits) are subjective but you need those results before you can be advised on whether or not to drain off some of your pool. Probably so, but you need to confirm that before you dump 1/2 your pool unnecessarily.

 

[yuyiwen]

Just did a test with taylor kit. CH=800, CYA=160. Since I have SWG, the target CYA is 70-80 according to pool school, right? I also tested my tap water, CH=150. Should I replace all water and bleach my pool or should I just replace enough water to get my CH in 250-350 range? I used Pumas stone and removed most of the circular stain. But I still have some darker shades (lower than circular stains in the picture) that could not be removed by pumas stone.

 

[Richard320]

Just did a test with taylor kit. CH=800, CYA=160. Since I have SWG, the target CYA is 70-80 according to pool school, right? I also tested my tap water, CH=150. Should I replace all water and bleach my pool or should I just replace enough water to get my CH in 250-350 range? I used Pumas stone and removed most of the circular stain. But I still have some darker shades (lower than circular stains in the picture) that could not be removed by pumas stone.

Replace half or a little more. That will bring CYA into range and get CH down to around 500 which is quite manageable if you adjust TA to keep the CSI (Calculated on pool calculator) close to zero.

 

[yuyiwen]

I am going to drain 75% of the pool water this weekend. I am wondering if I can chlorine wash the spa and shallow half of the pool to remove some of stains. I have some 6% house hold chlorine at home, should I go get some 12% chlorine to do the wash? Also, is it safe to not pump out all water after the chlorine wash?