Newbie: Calcium Hardness in a Minipebble Coated SWG pool

[PoolGuyTodd]

Hi Everyone,
1st post here so go easy ....

I did already search the forums and found a lot of varying information.

I have a 13k gal SW pool and the Taylor test kit that includes salt water testing. I'm fine with all the tests, and have everything in normal, except for my CH is 250, and the TFP app (Pool Math) on Android says it's low and that the normal range is 250-650, with ideal from 350-550.

Furthermore, I've owned this pool just over a month, and the pool guy hired by the pool installer says don't worry about it unless it goes below 100, and that (in southern California) he's never added CaCl2 to a pool.

So, you can see my confusion.

Help?

Thanks!

 

[mknauss]

Welcome to the forum!
You tested your CH at 250 ppm, which is in range. So no need to panic.
What is the CH of your fill water? As you just filled the pool, I suspect it is 150+ppm. And due to evaporation, as you fill the pool, the CH will rise. So correct, no additional calcium is needed.
Please fill out your signature when you can. Really helps us help you.

I suggest you read ABC's of Pool Water Chemistry.

 

[PoolGuyTodd]

That's great, and thank you for such a rapid response.

Here's my *only* further question: The only reason at all I have some confusion leftover is the ranges for CH in the PoolMath android app, which was created by TFP. That's where I got the 350-550 ideal range in my head (along with the 250-650 recommended range).

Does the app need to be updated? Because right now it's a bit misleading if 150-250 is really my "target range".

Does that make sense?

 

[mknauss]

The recommended range for CH for your pool type is 250 to 650 ppm. You stated your CH is 250 ppm. So you are in range. Not ideal range, but not everything is ideal. To protect your plaster at your low end CH, maintain a higher pH and a TA in the upper range.

What is the CH of your fill water? Your CH will naturally increase as you add that fill water to make up for evaporation.

 

[PoolGuyTodd]

I will check that and get back to you. Thanks again! (so the idea is to , if I'm reading you correctly, use CaCl2 or the like as a sort of last resort, because once you put the calcium in, the only way to get it out is to drain and refill the pool or part of the pool)

 

[mknauss]

(so the idea is to , if I'm reading you correctly, use CaCl2 or the like as a sort of last resort, because once you put the calcium in, the only way to get it out is to drain and refill the pool or part of the pool)

Correct. You might want to review Calcium Saturation Index (CSI) - Trouble Free Pool
At the end of the day, that is the factor you want to manage. The TFP Levels are built such that you do not have to worry about CSI IF you can stay within those lanes. But many of us in the SW USA cannot stay in those lanes.

 

[PoolGuyTodd]

so SORRY for the delay but THank You! to @mknauss for your recs. Yes I am in Orange County Ca so it's a challenge. My next step is to check my tapwater to see the levels in that, and then I'm going to start a new thread here (Yes, I've looked at many old ones ) about why does my TA stay around100-120 and my ph keeps rising, and I have to add 1/2 gal 31.45% MA a week or so. More to come!! (and ... LOVE this website AND the Android App which I use many times per week -- love the pool chemistry!)

 

[ajw22]

so SORRY for the delay but THank You! to @mknauss for your recs. Yes I am in Orange County Ca so it's a challenge. My next step is to check my tapwater to see the levels in that, and then I'm going to start a new thread here (Yes, I've looked at many old ones ) about why does my TA stay around100-120 and my ph keeps rising, and I have to add 1/2 gal 31.45% MA a week or so. More to come!! (and ... LOVE this website AND the Android App which I use many times per week -- love the pool chemistry!)

No need for a new thread. Keep all your water chemistry questions in one thread.

What is the pH and TA of your fill water?

Do you have an autofill on your pool?

 

[Jimrahbe]

Todd,

I suspect you are trying to keep your pH at 7.2... this will take a lot of MA.. Most SWCG pools like their pH to be right about 7.8, so you are just making things hard on yourself. Let your pH go up until it is 8.0, then only drop it down to 7.7 or so..

As far as TA goes, unless it goes less below 50 ppm, I would just leave it alone.. Adding acid over time will bring it down. Do not try to adjust TA just to get to some magical number.

As far as your pH going up, this is normal in a new pool, and/or if you have water features that are continually running.

Show us a pic of your "robot"...

Thanks,

Jim R.

 

[PoolGuyTodd]

Hey!!! You guys are all TOTALLY awesome!! Thank you for the super fast replies!!

(just updated my signature with all my stats)



So here's my robot, named Proteus Maximus. And I wanted to attach a pic that I think may be contributing to my pH / TA problems. We have an elevated spa and the waterfall generated by the pool pump running (currently) 12hr a day (probably drop to 8hrs +/- over winter, maybe 6) (living in Orange County, CA, where it's mild in the winter).

2 days ago I checked the chemistry, and added 1/2 gal of 31.45% Muriatic Acid (after these stats were obtained):
pH: 7.8
FC: 10
TA: 100
CH: 240
CYA: 90
Salt: 3000
Bor: 0 (I don't use boron/borates)
CSI: -0.06
Temp: 82


Here are my stats just obtained a few minutes ago:
FC: 8.5
TA: 90
CH: 240
CYA: 80
Salt: 3000
Bor: 0 (I don't use boron/borates)
CSI: 0.10
Temp: 84

Added about 1/4 gal of 31.45% MA

OK , y'all: hit me with your ninja-level knowledge assessment!

 

[Jimrahbe]

Todd,

Just so that we are all on the same page, please use the following format for all your tests... It makes it much easier for us to read and understand...

FC
CC
pH
TA
CH
CYA
Salt if needed..
CSI if you want..
Temp if you want


So 2 days ago your pH was 7.8 (which is perfectly fine) but you added 64 oz of MA, which should have decreased your pH by 1.2.. 7.8 - 1.2 = 6.4.. Why in the world would you do that???

If you had just left everything alone, you would have been fine.

Two days later you are adding MA again.. What was your pH then???

I like your Robot!!

The waterfall will drive your pH up.. It is what I use when I want my pH to increase...

Thanks,

Jim R.

 

[PoolGuyTodd]

I was following the PoolMathCalc app which suggests Dropping pH to 7.0-7.2 and then let the filter run (and my waterfall) to blow off the CO2 to get rid of TA, and thus lower that as well.

In spite of my Acid Bombing of my pool, pH hasn't budged, slightly increased actually.

Now I was told(by the pool installer and the "pool guy" they had get me started) to run the skimmer/filter/(and therefore spa waterfall) 12 hrs a day for a few mo and then over the winter (when we're not using the pool as much) 6-8 hrs a day to have at least one or two pool volume turnovers a day.

Does that sound close to OK? Am I insane? Are my Taylor test kits not working and i'll see the skin peeling off my kids from a pH of -10?

 

[Jimrahbe]

Todd,

Just leave your TA alone... But.. If you just can't help yourself, then lowering TA is a process, not a one time dump-and-run kind of thing..

When my TA gets above 130 or 150 and I want to lower it, it takes take me two days.. I start in the morning and measure TA and pH.. I turn on the waterfall and leave it on.. I then add enough acid to drop the pH to 7.0 or so.. I then retest in a two to three hours and do it all again, and then again in another two or three hours.. I do it all day and then quit at bedtime. I leave the waterfall on and then start again the next day.. At first the TA will hardly come down at all.. Eventually it will start coming down in bigger chunks. I keep going until it drops to about 50.. When I stop at 50, it will spring back to 60 within an hour or so and then very slowly start to come back up over a period of a few months.

With a CYA of 80, for "your skin to fall off" your FC would have to be above the SLAM level of 31, and even then your skin won't actually fall off, but we no longer recommend you swimming.

I try to keep my FC at my target of 5 or above... Running at 10 is not going to hurt you, are anything else..

Pool care is not like a game of darts where only a bull's eye counts.. It is much more like a game of hand-grenades where close, is plenty close enough.. You are making it harder than it needs to be..

Just to add to the pile that your pool builder is heaping on you.. Turnovers are a myth.. Chemicals keep your pool algae free, not the number of times you run your water through your filter. We have people here that only run their pumps for 2 or 3 hours a day.. When you have a SWCG, your pump run time should be based on how long it takes to generate the amount of chlorine that your pool needs. If you do that, then there is almost never a need to run your pump longer. Do you know the pool size that your salt system is rated for???

Thanks,

Jim R.