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Thread: Cal Hypo vs Calcium Chloride to increase calcium hardness

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    Cal Hypo vs Calcium Chloride to increase calcium hardness

    I'm a newbee to this forum- never been a member of any forum, so I hope this question is not a repeat. I'm also a new pool owner and trying to maintain it myself. Because I bought a house with a 20 year old pool, I found some issues with the pool- had trouble with algae and cloudiness. The local pool expert advised me to shock the pool with dichlor and never to use Cal Hypo or bleach. After 2 shocks of dichlor and some liquid bleach, the green turned to cloudy blue, so the expert then advised a flock, which did the trick. Crystal clear water. After a couple of weeks of good water (and high chlorine levels), I started noticing a little cloudiness and a green-brown scum forming on some of the seams (vinyl liner). After reading this forum, I suspected that my real problem was high CYA so I bought a Taylor test kit and found CYA off the chart (used distilled water to cut my pool water) and think the CYA was 150. Said expert advised me to shock with dichlor again to get rid of the cloudiness, then drain half the pool. I protested that dichlor would add CYA, which I am trying to correct. He assured me dichlor does not have CYA. I used liquid bleach instead, thinking that it was probably futile anyway until I got rid of the extra CYA. So I drained more than half the pool, refilled and got CYA to 60, and now I need to shock and re-balance. First question: does dichlor have CYA? It would seem like a very bad choice for my pool if it does. We have very low calcium in our tap water- I measured 0 calcium hardness in our tap water, and after refilling the pool, measured 40. Second question: with the vinyl liner, do I still need to try to get to 200 ppm calcium hardness? Third question, I've read that adding calcium can cause cloudiness- is that true if my CH is only 40? With the low CH, does it make sense to go ahead and use cal hypo for shock and to maintain FC until CH gets higher, then switch to liquid chlorine? Or should I just use liquid bleach and increase CH with Calcium Chloride? Which method will give less cloudiness?
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Welcome to TFP!

    Your pool expert is anything but an expert.

    Yes Dichlor has CYA in it, so does Trichlor which is what tablets are made of.

    For a vinyl pool there is no reason to add calcium and yes sometimes adding calcium can cloud the water.

    You should ignore the CH and use liquid chlorine / bleach to SLAM the pool and then for maintenance.

    The final thing you should do is never talk to that "expert" again. Read Pool School, ask questions here, and take control of your pool.
    Jason, TFP Moderator
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Thanks so much- sorry I didn't read your suggestions for new topics before writing my post. After filling the pool, lowering ph to 7.4 and adding 2 lbs of cal hypo (not being sure about using the calcium- wanting to shock but go slow), the FC = 12, CC = 0, PH = 7.8, TA = 140, CH = 40, CYA = 60. My next question is how do you control PH and TA separately? I am using muriatic acid to lower PH. I am afraid I will always struggle with high PH since our tap water has high PH and am not sure how the tap water will affect TA. Does liquid chlorine or bleach raise PH? I knew adding the cal hypo would raise PH, so I am glad to see your advice to not worry about CH and just use bleach.
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Bleach is effectively pH neutral, it will raise the pH when you add it, but lower the pH back when the FC is consumed.

    Just control the pH with acid and basically ignore the TA, it is a buffer for pH and will find a happy place. But, remember the pH test is inaccurate when FC is greater than 10ppm, so ignore it when the FC is high.

    You need to follow the SLAM process and your FC is still too low. [slam:bh2zif0p][/slam:bh2zif0p]
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Thanks again. I will follow the slam process. A few more questions: Can you guess what the yellow-green deposit is that I've seen? The last time I saw it was when I had the pool off while I was draining the pool and was not running the polaris. Is it algae growing, or inert deposits from metals or dead organic things? 2nd: do we need to brush once/week if we use the polaris several hours/day? The polaris does seem to remove the yellow-green deposits. 3rd: how often will I need to test for chlorine after finish slamming, to maintain the recommended 7ppm with a CYA of 60? Should I leave the CYA at 60 or go through the draining process again to try to lower it to 30. I am seriously considering getting a Pentair SWG. What would be your recommendation for a CYA level for a pool with a SWG?
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    If the Polaris is removing the "stain" then it is likely algae alive or dead.
    Brushing is always a good idea.
    You need to test and add bleach everyday to maintain it.
    For a SWG, we recommend a CYA 70-80ppm. Your current CYA is reasonable.

    Have you read Pool School? Many of these answers are these.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    I have now read all of Pool School. Thanks for the suggestion. Before starting the slam process, I decided to do an overnight test of my FC. It was 6.6 at 8:45 pm, then 5.8 at 6:50 am and 0 CC. This is less than the 1 difference that you allow to stop the slamming, and with the CC at 0, or at most .2 as measured by my Taylor test kit, do you think slamming is necessary? Pool school says to slam when CC gets to .5. I also read the post from waterbear on adding borax. Do you agree that is a good idea? It would seem to me that if it does what is claimed, then if you do get any algae, its growth would be retarded by the borax, letting the FC take care of it without worrying about slamming. But I guess that even with no algae, organics from swimmers might eventually lead to CC > .5. Is that correct? Do I understand correctly that slamming is the only way to burn off the CC? Thanks again for your help.
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Welcome to tfp, docelect

    Quote Originally Posted by docelect
    Before starting the slam process, I decided to do an overnight test of my FC. It was 6.6 at 8:45 pm, then 5.8 at 6:50 am and 0 CC. This is less than the 1 difference that you allow to stop the slamming, and with the CC at 0, or at most .2 as measured by my Taylor test kit, do you think slamming is necessary?
    Unless the water is not clear, then I do not think you need the SLAM process. By the way, there is really no need for the 25 ml sample size for the fas-dpd test, the 10 ml sample is sufficient (then each drop of the R-0871 is equal to 0.5 ppm).

    Quote Originally Posted by docelect
    I also read the post from waterbear on adding borax. Do you agree that is a good idea?
    I would maintain your pool for now without it and then decide if you need it...for many pools the benefit may not be worth the cost/hassle.

    Quote Originally Posted by docelect
    But I guess that even with no algae, organics from swimmers might eventually lead to CC > .5. Is that correct? Do I understand correctly that slamming is the only way to burn off the CC?
    No, normally bather waste is taken care of by the chlorine aready in the pool. If you are planning on having a heavy bather load swim party, then preemptively raising your FC up the the high end of normal is a good idea. The uv light from the sun does a great job with the CC in a normal residential outdoor pool. I have almost never seen CC>0.5 and I have had some heavy swimming sessions.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    I would disagree a bit here, a loss of 0.8ppm (4 drops) starting at that low FC seems iffy to me, especially given the clouds you get when brushing. I would suggest raising the FC up to SLAM level and doing the OCLT again, if you pass, just let the FC drift down ... still safe to swim. If you fail, then continue the process.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    With the polaris off, I continue to get small deposits of yellow-brown slime near the return jets- perhaps a few square inches worth each day. I had the sand replaced in my filter a couple of months ago. But it seems to me that the deposits must be coming out of the filter. I back-flushed two days ago. Any further thoughts?
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Has the pressure risen by 20%? Have you backwashed? Just raise it to SLAM level, run the pump and do the OCLT.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Since changing the sand, the pressure never rises more than 1 or 2 psi over a 4 or 5 day period, then I back flush. I last backflushed 2 days ago before doing a OCLT. I will slam when I get a chance later this afternoon- before nightfall, and do the OCLT.
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    jbliz is right, your water does not sound clear (that includes the deposits you are seeing) so the SLAM process should be done. Sorry about the poor advice above.

    I would lower your ph down to 7.2-7.4 before starting the SLAM.

    Make sure you brush a lot during the SLAM since you are getting growth on the walls.

    What is your "clean filter" pressure?
    Does you pressure gauge go to 0 when the pump is off.

    Quote Originally Posted by docelect
    Since changing the sand
    Side note...in mosts cases there is no reason to change out sand.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    I think you may be backwashing too often which is not helping your filtering. You should backwash when the pressure rises 20-25% over the clean pressure. Some people only do this 1-2 per year with a clean pool.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Filter pressure is 18.5 now. Its lowest point is about 17.5. Gauge does go to 0 when pump is off, so I think its working. I will make sure to lower pH before slamming. I'm unclear on one thing: The pool calculator says my slam level should be 18 for my CYA of 60, but the CYA/Chlorine chart says shock level is 24. Which is right? Rather not put in the extra couple of gallons of bleach if I don't need to.
    docelect
    30k gallons in-ground vinyl
    1.5 hp pump 300 lb sand filter
    Polaris cleaner, T15 Hayward SWG
    Jackson, Mississippi

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    linen's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    There is a new/modified poolcalculator here called PoolMath: http://www.troublefreepool.com/calc.html It has the same SLAM numbers as the chlorine/cya chart...use those. The numbers in the old poolcalculator work, but the chlorine/cya chart is a little more aggressive/faster.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Mod Squad jblizzle's Avatar
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    Re: Cal Hypo vs Calcium Chloride to increase calcium hardnes

    Forget about poolcalculator (although it will still work just a little slower). Use PoolMath (link in my signature) which now matches the chart.

    If your clean pressure is 17.5, then backwash at 21-22 psi.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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