Why does pool school say to test CH weekly? I thought it stayed the same unless you add water.
Why does pool school say to test CH weekly?
- Thread starter TomAtlanta
- Start date
CH can go up due to curing of plaster, or from cal-Hypo. It is important to maintain your CH levels because if it gets too high it can cause scaling (which can be really expensive to fix). Low CH can actually start to absorb calcium out of the pool walls and floors causing damage. Partial Drains and of the pool or reverse osmosis are the only ways to lower CH.
After a while, once you get used to the composition of your pool water, you may not need to test CH so often. But if you have: 1.) plaster less than 1 year old, 2.) cal-hypo that you use frequently, 3.) fill water that is high in calcium, you probably need to test once per week.
- May 3, 2007
- 16,833
- Pool Size
- 20000
- Surface
- Plaster
- Chlorine
- Salt Water Generator
- SWG Type
- Hayward Aqua Rite (T-15)
I agree with 1 & 2 but I have high CH fill water (~300 ppm) and I have found that the CH rise is very predictable and occurs fairly slowly so I usually test bi-monthly.
I would encourage anyone who first starts to test and manage their own pool to do CH test weekly until you verify that it is stable. In most pools, it is quite predictable and you can drop back to whatever your comfort level is.
As you open each Spring, I would again suggest a weekly test for a couple or three weeks so you can verify it's stability once more.
As you open each Spring, I would again suggest a weekly test for a couple or three weeks so you can verify it's stability once more.
Thanks for the info. The fill water here here is low in calcium. Before adding chemicals it was 50. I added calcium and gradually brought it up to 250. I am not using cal-Hypo, and it is an old plaster pool so I don't expect it to change based on what has been said here, but I'll test weekly for a while and see if it is stable.
My ch has been at 350 since we filled. It has never changed. I did have my pool cover pump pumping the water into the pool over the last week to lower my salt level some, got 3" of rain. I'll test today to see if the ch went down also.
I don't understand how this works. Does that mean that over 10% of the pool water was replaced by rain, or does it mean that the calcium is somehow removed from the water, or does it mean something else that I don't understand?
It means that calium-rich water was replaced by calcium-free rainwater and/or the pool level went up with the rain, diluting it.TomAtlanta said:
it just means that rain water has zero calcium in it so therefore when it rained it naturally dropped the CH level. it's my understanding based on reading this forum that calcium hardness never leaves the water unless there is reverse osmosis, partial refill or splash out.
for example last week, i tested my CH before we were supposed to get some substantial rain. my CH was about 450 ish and i was able to capture a bit over 4 inches of rain and it lowered my CH to 400 ish. pretty close to where it needs to be. that's down from nearly 550 in early december before all of the rains have come.
hope this helps.
for example last week, i tested my CH before we were supposed to get some substantial rain. my CH was about 450 ish and i was able to capture a bit over 4 inches of rain and it lowered my CH to 400 ish. pretty close to where it needs to be. that's down from nearly 550 in early december before all of the rains have come.
hope this helps.
TomAtlanta said:
I was surprised how much it went down, in hind site I prob should have left it at 350 because at 310 my csi is approx -.50.
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