My CH level was 410 last year. Now it is at 460. How high is too high? What are some ways to bring this down. I tested the refill water and it is 210. The PoolCalculator says to refill 63% of my pool water. Any other ways to do this?

The only other way to reduce CH is by a reverse osmosis treatment. There are a few pool companies who are able to offer this service, but for most of us a drain and refill is the only option. What area do you live in?

I'd be interested in why the CH keeps rising when the fill is 210. I'm guessing you may be using Cal Hypo. If so may want to consider a different option for chlorination.

It's rising because as water is added, calcium is added, which stays in the pool when the water evaporates. So calcium continues to build up.

For example: almost one year ago, my CH was 350. My fill water is 210. In Tucson, we have about 80 inches of evaporation per year. My pool averages ~48" deep. So in an average year, a little less than two entire pool volumes evaporate and are refilled (leaving their calcium behind!). My pool is now at about 650 CH, with not a single granule of cal-hypo or calcium chloride added. Gotta love Arizona!

CH does not go away, so as you add water, you add calcium. Even 210 fill water will continue to build until you are out of range.

CH should be between 200-400 ppm. You can go over 400, but you run the risk of scale build up on the waterline tile, pump shafts, heat exchangers, etc., and it makes it a little harder to maintain the pool. Drain and refill (shudder!) or R/O are your only options to lower the levels.

Goes with the weather. Here in Canada, pools are closed about 5 months a year, drained every year too. Makes Cal-Hypo a reasonable choice.

OP, I'd strongly wish for more informations about your situation:
Chlorine type used?
Is it possible to drain and refill?
Is it mandatory to drain and refill?
What products have been added to your pool on a regular basis?
(This might be because you've been pool stored into buying calcium chloride.
Don't panic as of yet, you still need them for pool parts, and they are
probably not aware they did this to you, if they did)

The only real drawback to having high CH is the need to keep a lower PH/Alcalinity to avoid scaling, as per Langelier's index ( or Chemgeek's revised saturation index, of course.)

Yep that all makes total sense. Forgive me for my idiocy. I'm used to the Houston area where rain water has a large impact to our pool consistency so drain and fill usually isn't a problem.

I have been told rising the pH will cause calcium carbonate to form and will lower Calcium Hardness.

However, this means rising the PH then reducing it with the addition of chemicals. This is also not something I've tried, so I cannot recommend it nor tell you how to proceed.

That said, if someone DO KNOW the technique and is willing to teach it: I'm all ears.

PS: There's no stupid question. Not asking leads to assuming which leads to Trouble-Loaded Pool...

[Edit] Should have read: PS: No, your point was perfectly valid. We can't know, for now, what is the cause, because we do not have enough infos to work with. Which probably wasn't relevant from OP's point of view.[/End Edit]

Plug some numbers into Pool Calculator. See what raising and lowering TA and pH have on the CSI. Even play with the CH. There will come a point where it's very difficult to keep the CSI close to zero. That's when you need to worry. I'm at that point with my pool. I drained about 800 gallons the other day to get CH down to 3 digits. I'm really hoping we have an early wet winter here, to get some calcium-free water in the pool.

For what it's worth, the water is crystal-clear and sparkly. When the water's still, it's possible to kneel down poolside and see that the screws holding the cover on the main drain are phillips head - 8 feet down!

Thanks for all the good responses. Sorry it took so long to write back. I live near Allen, TX. I am a full subscriber to BBB. I use no pucks or shock. Only baking soda, bleach, borax, and MA. So the idea that evaporated water leaves the CH behind makes sense. In the summer, it is common to lose 1/2 inch every day. But my CH never decreased throughout the summer as I refilled it. Should I just put the hose on the pool floor and let it rip for a day? My CSI stays at 0 or slightly negative so I don't think there is an issue there. Please advise. Thanks again!

Back to answer your original question (because this thread seems to have gotten unnecessarily complicated) the ONLY TWO ways to reduce CH is to drain and refill or purchase a R/O service.

I do not believe you have R/O available in your area so partial drain and refill is your option.

I have a similar problem. My pool has only been refilled for a month and I already get readings over 400ppm. I'll keep an eye on it to see if it goes up higher. We should be seeing some rain starting sometime late October hopefully, so maybe that will help?

Also, would new plaster cause high CH readings? I know that it tends to raise the PH a lot because there's a lot of dust and curing in the first 30 days.

Yes, new plaster will increase the CH levels as it cures out. Keep an eye on it and don't let it get too high!

Thanks! So, the main solution is the drain and refill I guess? Kinda hate doing that with CA already low on water. I'll keep checking it.

The "standard" solution is to drain and refill (although you only get back as good of water as the water company provides you ), as R/O is not available in all areas yet. Hopefully that will change one day, especially in drought areas (like California).

I don't really have a way to drain. I was going to just put the water hose on the pool floor and let it rip. The overfill drain leads to the back of my property. I assume this will work? How else can I drain the pool?

A submersible pump. Or hook a hose to the backflush port on the filter and let 'er rip. If there's a significant elevation difference, a garden hose or two used as a siphon will empty things out.

I struggle with high CH every year. Our fill water is about 250 ppm so with evaporation, it doesn't take long to get well above 400 ppm. The highest I have ever had the CH is about 800 ppm and then I had to keep the PH slightly lower to compensate. The key is to keep an eye on CSI and don't let that get too high but with lower PH, you can let CH get fairly high but eventually, you will want to replace some of the water.

This year I did an in-place refill where I extracted water at the same time I filled the pool. This can work if you can keep the water still and attempt to separate the new and old water. Filling the bottom while taking off the top should work if the new water is colder than the old water which it should be this time of year.

I actually do the opposite, fill from top while pumping off the bottom, during the winter because our fill water during the winter has less CH so less new water is needed. Our city uses more surface water then well water during the rainy season which might be the case in your area so check with your local water district.

Richard320 and mas985,
Can you elaborate on how to pump the water out? Also, there was mention on connecting the hose to the backflush port? Can you help me understand how to do this? Also, how to use a hose as a syphon? I was just going to put the hose in the bottom of the pool and turn it on. This won't work?

The backwash outlet is usually at your filter, so the manual to the filter will tell you how to do it. The only thing you need is a backwash hose (sold at any pool store) to connect to the backwash outlet and then route it to a drain. You basically turn off the pool pump, turn a handle on the filter and turn the pump back on and it will pump the water out of the pool. The backwash is normally used to clean the largest debris off your filter.

However, I used to have a small cartridge filter and there was no backwash outlet on that, so it's not a guarantee you have it.

Hope this helps