Trouble with high CH
- Thread starter VondaP
- Start date
I wanted to post my current numbers
FC 7
CC 0
PH 7.4
TA 110
CH 525
CYA 50
Borates 50
FC 7
CC 0
PH 7.4
TA 110
CH 525
CYA 50
Borates 50
Those numbers are fairly good, particularly if the pool has been cooling off. With a water temperature of 70 degrees your calcite saturation index would be 0.02, which is excellent. You do not want TA or CH to go up if you can help it. As long as you keep the PH just a little on the low side, 7.2-7.6, and neither TA or CH goes up, you should be fine.
Long term, presumably in the spring, you should think about lowering either TA or CH or both. Lowering TA is easier, though it is some work.
Long term, presumably in the spring, you should think about lowering either TA or CH or both. Lowering TA is easier, though it is some work.
Thank you for responding Jason. I posted my numbers to give an idea of how my pool is doing. Now that I know I have calcium scaling, I was hoping you could help me in how to remove it.
Thanks again,
Vonda
Thanks again,
Vonda
There are two basic approaches to removing calcium scaling. One is to bring your calcium saturation index down to somewhere around -0.5 to -0.7 and hold it there for a couple of days to weeks while brushing any scaled areas at least once a day. Adding sequestrant can also help using this approach. The low saturation index will cause the scale to start to dissolve back into the water and brushing will help break it up and speed the process. Using this approach will be more complicated in your case, because you will need to lower both TA and CH levels noticeably to be able to get your saturation index low enough without taking PH too low. There are also more drastic forms of this treatment, where the saturation index and PH are brought quite a bit lower than that to speed the process and other chemicals are added to speed the dissolving of the scale, but this requires bypassing any heater and careful attention.
The other approach is acid washing. Muriatic acid is applied to the scaled areas and dissolves the scale. If large areas are scaled you will need to drain the pool to be able to apply the acid. If only small areas are covered they can often be handled with a sprayer that can be used underwater.
The other approach is acid washing. Muriatic acid is applied to the scaled areas and dissolves the scale. If large areas are scaled you will need to drain the pool to be able to apply the acid. If only small areas are covered they can often be handled with a sprayer that can be used underwater.
Thanks so much. I am going to try the simpler approach of lowering the TA and CH. I will check the stickys and see how much water I need to replace. Where should I keep my PH?
Thanks again,
Vonda
Thanks again,
Vonda
You should aim for a PH of between 7.0 and 7.2. PH below 7.0 can damage metal components, particularly copper based heat exchange coils in pool heaters.
You should also test your fill water to see what TA and CH levels it has, to help you figure out the water replacement.
You should also test your fill water to see what TA and CH levels it has, to help you figure out the water replacement.
My tap water numbers:
CH - 100-125 (last time it was 100, this time it is 125)
TA - 100
How do I incorporate these numbers in deciding how much to drain? My pool is about 8 months old, do I buy Jack's Blue stuff? I'm ready to tackle this while our weather is still in the 80's.
Thanks so much,
Vonda
CH - 100-125 (last time it was 100, this time it is 125)
TA - 100
How do I incorporate these numbers in deciding how much to drain? My pool is about 8 months old, do I buy Jack's Blue stuff? I'm ready to tackle this while our weather is still in the 80's.
Thanks so much,
Vonda
If you do a 50% drain and refill with your tap water having a CH of 125, you should end up with CH at about 325. Since your tap water TA is close to your pool TA, nothing significant will happen with TA. You can take care of the TA after CH.
Replace water as ktdave suggests first, then add some sequestrant, then lower the TA to perhaps 60 or 70 using acid and aeration, then hold the PH around 7.0-7.2 for a while.
Thank you all so much. Will the regular nylon brush I have work or should I buy the metal/wire type?
I will be ordering Jacks blue stuff. How many bottles do you all think I need?
Vonda
I will be ordering Jacks blue stuff. How many bottles do you all think I need?
Vonda
A mixed wire/nylon brush will work better on stains than straight nylon. You don't want to use a wire brush on new plaster, but if I remember correctly you are over eight months old so it should be fine.
I would try three bottles of the Blue Stuff. The suggested dose is 1 bottle for each 10,000 gallons, but you might as well put in the entire third bottle.
I would try three bottles of the Blue Stuff. The suggested dose is 1 bottle for each 10,000 gallons, but you might as well put in the entire third bottle.
I received my Blue Stuff and am draining today. After I've replaced the water and added the sequesterent, do I keep the pump running 24/7 - for how long?
Thank so much, I am so hopefull.
Vonda
Thank so much, I am so hopefull.
Vonda
There isn't any need to keep the pump running 24/7. You do want it on for several hours after adding the sequestrant to make sure the sequestrant mixes in throughly, but other than that the pump run time is not critical.
The next step, after lowering CH with the partial drain and refill, is to lower TA down to around 60-70. This is done by bringing PH down to 7.0-7.2 with muriatic acid and then aerating the pool. The acid will lower both PH and TA while the aeration will raise PH without changing TA. When the PH gets back up to 7.8-8.0 you repeat the cycle. It may take a couple of cycles of this to get TA down to the right level. You can aerate with spa jets, a fountain, pointing a return up so it breaks the surface, an air compressor, rain, kids splashing, etc.
Once you have done that you simply hold the PH around 7.0-7.2 and brush the stains regularly. This approach can be fairly slow, it takes days to weeks, but is reasonably safe and comparatively simple. You know when you are done by watching the stains, which should show visible progress well before they go away completely.
The next step, after lowering CH with the partial drain and refill, is to lower TA down to around 60-70. This is done by bringing PH down to 7.0-7.2 with muriatic acid and then aerating the pool. The acid will lower both PH and TA while the aeration will raise PH without changing TA. When the PH gets back up to 7.8-8.0 you repeat the cycle. It may take a couple of cycles of this to get TA down to the right level. You can aerate with spa jets, a fountain, pointing a return up so it breaks the surface, an air compressor, rain, kids splashing, etc.
Once you have done that you simply hold the PH around 7.0-7.2 and brush the stains regularly. This approach can be fairly slow, it takes days to weeks, but is reasonably safe and comparatively simple. You know when you are done by watching the stains, which should show visible progress well before they go away completely.
After draining over 50% of the water my CH is at 375. I really expexted it to go down to 325. I also added the MA before I added the Blue Stuff (about an hour before). I sure hope I didn't screw it up by adding the MA first.
Vonda
Vonda
The order of adding the acid and the sequestrant doesn't matter. You are making great progress.
Jason,
So far so good. My PH is at 7.0 and I've been brushing several times a day. When the PH rises again to I have to add 3 more bottles of sequesterant and lower the PH?
Thanks for your help,
Vonda
So far so good. My PH is at 7.0 and I've been brushing several times a day. When the PH rises again to I have to add 3 more bottles of sequesterant and lower the PH?
Thanks for your help,
Vonda