New owner water balancing help

Trevor916

Member
Sep 15, 2020
5
Roseville, CA
Just received my TF-100 kit to replace the bad excuse of a tester I purchased when we bought the home (HDX, simple FC/pH kit). Was excited to see the actual levels of the pool, not so much to see the results.

Backstory - Purchased new home, first pool, have been in the house ~1 month

Before TF -100, HDX kit showed ~4 FC // 7.8 pH // 140 TA. The FC 'seemed' fine (prior to understanding the relationship to FC/CYA), and did some small adjustments with the TA with acid treatment while monitoring pH. When it got to 7.2 did aeration to bring up. TF-100 arrived today and did full tests as detailed below;

FC: 7.5
CC: 0
pH: 7.5
TA: 100
CYA: 100
CH: 550

While I achieved my initial goal of lowering the TA and brining back up the pH, was surprised about the FC reading being so much higher than the HDX kit (shocker) until I saw the CYA readings. From my readings on TFP, that was a bummer.

#1) While my initial thought was FC was super high, PoolMath indicates I should be closer to 11. I hate to ask the dumb question if this is accurate, but maybe I'm still in shock. Is this true?

#2) The obvious solution to above problem (High CYA) is drain 1/2 of the pool and dilute to bring closer to 50ppm. Not exactly feasible with us just moving into the new home, but we can work that into our long-term plans as long as the above metrics don't strike anyone as priority fix. Any immediate concerns come to mind?

#3) Final uncertainty is the high(er) CH on the spectrum, which I guess would could be solved with draining/dilluting (2-1 solution for above). Seems like our area has high calcium in the water so bringing in outside water might be only approach, although haven't read enough to know if there is a way to treat with other methods. Thoughts/advice would be helpful.

Thanks TFP!
 
Last edited:

YippeeSkippy

Mod Squad
LifeTime Supporter
Jan 17, 2012
14,620
Evans, Georgia
Trevor, your CYA results are 100, which actually may be higher but the vial stops there. So the solution is to take equal parts of pool water & tap water and mix well. Then use this as your "pool" water portion of the CYA test, but double the results.

I fear a water exchange *is* in your future, unless you want to keep putting insane amounts of liquid chlorine in the pool to keep it algae free. How are you sanitizing now....and how do you want to in the future?

Please test your fill water for calcium hardness. Even your hard water can be dealt with by monitoring your CSI (on PoolMath) and tweaking your pH to the lower end of the scale. We have many folks out west who have the same problem as you- high calcium fill water & evaporation causing CH to rise. @Richard320 and @mknauss are both a good examples.

Maddie
 
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Trevor916

Member
Sep 15, 2020
5
Roseville, CA
Thank you @YippeeSkippy ! Completed your suggested tests;

Tap water CH: 1 Drop of R-0012 immediately turned blue, so 25ppm or less. Don't know how quickly that would rise pool CH should we partially drain?

50/50 Pool/Tap CYA (double results): 90. I know the line stops at 100, which was exactly where my previous test ended. I think my dilution was slightly over 50/50, so assuming 95-105 is a good range with reasonable accuracy.

Seller left a large amount of Trichlor tablets (now I know where the CYA came from) that I've used once in the Rainbow 320 chrolrinator until I figured out what's what. Now that I know the CYA I plan to discontinue use immediately and switch to liquid.
 

Oly

Gold Supporter
Jun 28, 2017
1,656
Fresno, CA
Trevor my situation was similar to yours and you can find my first thread link in about this issue in my signature below. Your issues can be corrected with a partial drain and it will help make maintaing your pool much easier. In the short term keep your FC in the target range FC/CYA Chart and watch your calcium saturation index to avoid calcium scale and plaster damage going forward.
 
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mknauss

Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
33,053
Laughlin, NV
Tap water CH: 1 Drop of R-0012 immediately turned blue, so 25ppm or less. Don't know how quickly that would rise pool CH should we partially drain?
Your tap water CH is very low. So there is no reason to lower the CH, but if you need to drain some water to lower the CYA, that will lower the CH anyway. I suspect a previous owner used lots of cal hypo shock in the pool.

You may want to use cal hypo shock at times to maintain your CH at or above 250 ppm, if necessary.
 
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Trevor916

Member
Sep 15, 2020
5
Roseville, CA
Thanks all! Will plan for a partial drain in the near future. Seems like the logical thing especially as we switch to liquid.

In the meantime, sounds like we need to raise FC levels for the higher CYA. Hopefully not for long

Much appreciated
 
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Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Thanks all! Will plan for a partial drain in the near future. Seems like the logical thing especially as we switch to liquid.

In the meantime, sounds like we need to raise FC levels for the higher CYA. Hopefully not for long

Much appreciated
If you have no algae, there's no reason to rush to lower CYA. You can bring it down slowly. I have a spigot on my return line so I can hook a garden hose to it and run pool water onto the lawn. Or down the storm drain to make room for rain water. I've even recently run a few hundred gallons of nice warm pool water down my sewer cleanout after snaking it.

As long as you maintain proper FC/CYA you won't get algae so there's no problem with the high CYA. You won't lose significantly more liquid chlorine daily than at a lower CYA, you'll just need a bunch to get up to where you want to be. I started out with CYA more than double yours and couldn't drain due to water restrictions so I was swimming in 20+ FC for months, no problem.

550 CH is quite easily manageable. Only when you get about 800 do you really have to watch the pH and TA.
 
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Trevor916

Member
Sep 15, 2020
5
Roseville, CA
Thanks @Richard320 , that's encouraging. pH and TA have been very stable. Ideally I'd like a lower FC but nice to know we can place that lower on our priority list. Water is crystal clear. Do have a couple fresh small iron stains, found a rusty nail in the bottom of the pool partially under the drain cover. Tried the vitamin C tabs which helped but I have the feeling the FC is already too high to have a significant impact. Will add that to that "nice to have" list down the road with a full AA treatment once we have time to drain, lower CYA, giving us room to lower the FC before we rebalance.