Long Time/First Time

[AndyHaj]

25 year pool owner here, but much more recently found TFP and the Pool Math app so I feel much more empowered. Just purchased the TF-Pro test kit and already see the benefits of no longer relying solely on pool store results and advice. Only major negative so far is the ph testing....increments of .3 not very precise, but my biggest issue is that I do not see any real color variation between the 7.5 and 7.8 visual scale. Am I missing something? Also, because of what I learned on TFP, I am focusing on maintaining good CYA levels. The CYA test seems a little subjective in terms of when the black dot disappears...variables such as how much light, does it have to absolutely completely disappear, what backdrop, etc. Again, any advice welcomed.
Lastly, to control CYA build-up and based on what I read here I am drastically cutting back on the trichlor tabs and only use when I'm away for for extended periods. I was at CYA of 95 now down to 55 and dropping. Yes, I know you all advocate liquid chlorine, but with a brand new vinyl liner ($$$) I am hesitant. For the past few weeks to control CYA I have been using CalHypo for both shock and sanitizing...for my 18,700 gallon pool typically weekly shock with 24 oz 55%, then every few days 8 oz trichlor. Seems to keep chlorine levels good and since my starting calcium is below 200, no concern now about too much calcium. Honestly I'd rather deal with high calcium down the road than high CYA. Any thoughts on this approach, and does supplementing the weekly shock with 8 oz CalHypo every 2 days seem ok?
Many thanks.

 

[Mdragger88]

Vinyl liners can get scale. Its not easy to deal with once it occurs.
What is your fill water ch?

Liquid chlorine will not damage your liner if used properly-
Pour slowly infront of a running return and brush the area. Don’t allow it to pool on the liner.
Undissolved Cal hypo can easily bleach your liner.

If you maintain adequate fc for your cya all the time (above min) you should never need to “shock” your pool.

Give the pool what it needs when it needs it (before fc falls too low).

 

[Newdude]

Hey Andy and Welcome !!!

All 7s are equally OK for Ph, especially for vinyl. You're basically looking for orange, purple, or not time yet.

If your ph is a 60 or 70, you shouldn't need to adjust the Ph. I haven't touched mine yet this year and don't expect to.

How do you add the tabs ? A feeder, floater or the in the skimmer ?

 

[AndyHaj]

Thanks for the feedback. When I do use trichlor tabs (now rarely) I have a chlorinator. I always pre-dilute CalHypo before adding so avoid vinyl bleaching issues. Not sure the calcium level of fill water - will have to check with water company. I will try the approach to avoid regular shocking and just keep FC at the right level. But not sure what you mean by ph a 60 or 70???
BTW my alkalinity is 110, which allowing for the CYA adjustment downward brings it in line with the vinyl liner vendor's recommendation of alkalinity of 80-100.

A few other thoughts to share:

I think the Pool Math app is great! I especially like the "Effects of Adding" section and now I never add anything without first knowing the impact on my pool chemistry.

As I have learned (finally) about CYA, I'm amazed how little the pool stores understand it. When I asked about it I often got blank stares. The two stores near me use the same "highly regarded" testing system that actually says acceptable level of CYA goes up to 200! Using the 7.5% factor, you would need FC of 15 to be effective.

For many years I would open my pool in the spring to very cloudy water that would need 20+ pounds of 73% CalHypo to get a chlorine reading. I finally found an obscure article online that explained that a covered pool (mine is solid with water bags) at least with northeast winters will result in a chemical reaction over the winter that breaks down the CYA and produces some type of ammonia that causes the Spring problem. That also explains why my CYA in the Spring would be so much lower than at closing. Now that I understand CYA I always close with good readings and now open in Spring to crystal clear water. Hopefully someone out there will read this and go "Eureka!"

 

[Newdude]

But not sure what you mean by ph a 60 or 70???

My bad. I meant TA. The industry recommends a TA of 80 to 120 assuming heavy tab use which lowers the Ph (from the cyanuric acid). Stop the pucks and there's no reason to try to pull the Ph up, but the advice remains unchanged.

So we target a lower TA to help keep the Ph from rising like it naturally does without frequent acid doses.

As I have learned (finally) about CYA, I'm amazed how little the pool stores understand it. When I asked about it I often got blank stares.

Someone at the top *has* to know. They have to. Lol. But they ignore it for sales reasons because a milliom swamps are profitable. The little guy you'll ever meet never gets the memo and only knows what the large company reps taught them. Which is to sell products. Lots and lots of products. Harmful products even. Then they have a spendy cure for that too.

Many counter people *cough* 15 year old kids *cough* honestly think they're helping people. The computer printout couldn't possibly be wrong. Except its designed to sell products. The 'free' test often suggests up to 8 products, with #s in range. There aint no free about it.

That also explains why my CYA in the Spring would be so much lower than at closing

It degrades a couple ppm a month, plus any draining for closing, plus any rain dilution if using a permeable cover. During the season it's hardly noticeable, but when you walk away from the pool for up to 8 months in the northeast, it adds up. Particularly with a mesh cover and 2ft of off season rain. and also melted snow.

 

[AndyHaj]

Newdude - thanks. My winter cover is solid so little if any rain/snow gets in, plus I don't drain any prior to closing. But I understand there is a little normal monthly degradation. However I was going from CYA at 90+ to almost zero over the winter when I was having the opening problems.

Another topic - Don't get me going on pool stores and phosphates! More recently pushing expensive products to reduce phosphates. I've found that if you control algae (FC levels and as needed algae control) it doesn't matter if phosphates that algae eat are present.

 

[Newdude]

However I was going from CYA at 90+ to almost zero over the winter when I was having the opening problems.

Did it take copious amounts of chlorine to fix every spring ? Ammonia from soil bacteria is a beast to deal with. While always possible it isn't common and the pool owners usually know about it because of how miserable it is.

Ammonia - Further Reading

www.troublefreepool.com

I've found that if you control algae (FC levels and as needed algae control) it doesn't matter if phosphates that algae eat are present.

Exactly. Set up a buffet in the middle of the Sahara desert. Ain't nobody showing up to eat the people food. So what you left it out. Lol.

But not needing algae control isn't profitable, so they'd rather you have algae and need lots of products to control it. We do the ounce of prevention whoops a pound of cure thing here.

 

[AndyHaj]

Did it take copious amounts of chlorine to fix every spring ? Ammonia from soil bacteria is a beast to deal with. While always possible it isn't common and the pool owners usually know about it because of how miserable it is.

Ammonia - Further Reading

www.troublefreepool.com

Exactly. Set up a buffet in the middle of the Sahara desert. Ain't nobody showing up to eat the people food. So what you left it out. Lol.

But not needing algae control isn't profitable, so they'd rather you have algae and need lots of products to control it. We do the ounce of prevention whoops a pound of cure thing here.

Thanks for the ammonia articles. How would soil bacteria get in a pool with non-permeable cover? Anyway, now that I control the CYA it is not a problem. Yes, it would take 20+ pounds of 73% CalHypo to get a chlorine reading and then some more to maintain it. Expensive, and then you can imagine the rebalancing needed afterwards.

 

[Newdude]

Yes, it would take 20+ pounds of 73% CalHypo to get a chlorine reading

Oof. That's 96 FC or 17+ gallons of 10. Maybe it was ammonia

How would soil bacteria get in a pool with non-permeable cover?

It can blow under a safety cover that's billowing in the wind, or wash off the deck under it, or a tarp typ of cover..

 

[Mdragger88]

You can test your fill water ch yourself- no need to ask someone

The reason I mention it is that ch in the pool is not lowered by evaporation, only actual replacement (drain then refill)
- as you add water to replace what has evaporated your ch will increase overtime.

 

[AndyHaj]

You can test your fill water ch yourself- no need to ask someone

The reason I mention it is that ch in the pool is not lowered by evaporation, only actual replacement (drain then refill)
- as you add water to replace what has evaporated your ch will increase overtime.

Good point, thanks. I'll test it. My guess is fill water ch is ok since earlier this year to lower CYA I drained about a foot and refilled.
BTW I had discovered a while back your same point about evaporation and CYA.

 

[AndyHaj]

Fill water ch is 175-200....about as expected?

 

[Mdragger88]

Fill water ch is 175-200....about as expected?

It’s different for every location-
You do not have low ch fill water so you should cease use of calcium containing products as your ch level will increase over time as you replace water lost to evaporation.
If you remain on your current diet of cal hypo you’ll be trading your previous high cya problem for a high ch problem.
This is unnecessary and completely avoidable by simply using liquid chlorine for daily chlorination.

 

[AndyHaj]

It’s different for every location-
You do not have low ch fill water so you should cease use of calcium containing products as your ch level will increase over time as you replace water lost to evaporation.
If you remain on your current diet of cal hypo you’ll be trading your previous high cya problem for a high ch problem.
This is unnecessary and completely avoidable by simply using liquid chlorine for daily chlorination.

Thanks and understood. My quandary with liquid chlorine is that I have an Aqua Genie so the only return is in the same place as the intake. Would be impossible not to have lots sucked right into the filter.

 

[Mdragger88]

Considering the aqua genie would prefer to have you adding trichlor directly to the skimmer (if i looked at the right model) which we never recommend, a little liquid chlorine getting by should be fine & much preferable to that.
Use the brush to mix it in the stream of the return as you pour. It disperses very quickly in to the pool water this way.
How do you add acid when you need it?

 

[AndyHaj]

Considering the aqua genie would prefer to have you adding trichlor directly to the skimmer (if i looked at the right model) which we never recommend, a little liquid chlorine getting by should be fine & much preferable to that.
Use the brush to mix it in the stream of the return as you pour. It disperses very quickly in to the pool water this way.
How do you add acid when you need it?

For both dry acid and CalHypo I dilute in about 3-4 gallon tub then slowly pour around edge of deep end.

 

[AndyHaj]

For both dry acid and CalHypo I dilute in about 3-4 gallon tub then slowly pour around edge of deep end.

Also I switched to a chlorinator attached to the filter some years ago for that very reason - didn't like trichlor being introduced to the skimmer. Also, it required 1 inch tablets instead of 3 inch pucks which were hard to find and costly.

 

[Mdragger88]

We really don’t recommend diluting acid as you’re handling it twice that way and risking more spillage. I still can’t believe you only have one return. Do you have many dead spots?
Most round above ground pools only have one return near the skimmer pointing away from it, the circular shape helps some with circulation. there’s generally no issue with adding liquid chlorine or acid in the way we recommend with them.

 

[AndyHaj]

We really don’t recommend diluting acid as you’re handling it twice that way and risking more spillage. I still can’t believe you only have one return. Do you have many dead spots?
Most round above ground pools only have one return near the skimmer pointing away from it, the circular shape helps some with circulation. there’s generally no issue with adding liquid chlorine or acid in the way we recommend with them.

Aqua Genie is designed for single inflow/outflow at same central point. No dead zones of any consequence in my rectangular inground over 25 years of use. See this for more insights on design:

Aqua Genie

NOT JUST A SKIMMER – AN ENTIRE POOL MAINTENANCE SYSTEM Because of its revolutionary design, the Aqua Genie removes surface debris up to ten times faster than conventional skimmers. At the sam…

www.hydrapools.com

The instructions for the dry acid (sodium bisulfate, not muriatic acid) say to dilute in 1 gallon tub.

So if I want to give liquid chlorine a try instead of CalHypo (assuming TFP says ok for vinyl), can you point me to info on strength to use and dosage/frequency guidance? Thanks.

 

[Mdragger88]

Aqua Genie is designed for single inflow/outflow at same central point. No dead zones of any consequence in my rectangular inground over 25 years of use. See this for more insights on design:

Aqua Genie

NOT JUST A SKIMMER – AN ENTIRE POOL MAINTENANCE SYSTEM Because of its revolutionary design, the Aqua Genie removes surface debris up to ten times faster than conventional skimmers. At the sam…

www.hydrapools.com

The instructions for the dry acid (sodium bisulfate, not muriatic acid) say to dilute in 1 gallon tub.

So if I want to give liquid chlorine a try instead of CalHypo (assuming TFP says ok for vinyl), can you point me to info on strength to use and dosage/frequency guidance? Thanks.

Glad the genie works ok for you.

We generally recommend using muriatic acid as dry acid contains sulfates which can build up in the water & cause various issues to concrete & metals. The risk is less with a vinyl lined pool that has no swcg or heater or uses low amounts & water is regularly exchanged which may be applicable in your case.

Liquid chlorine or a swcg are THE TFP recommended methods for daily chlorination in all pools.

Any unadulterated / plain sodium hypochlorite will do. The easiest to find is dedicated liquid chlorine in the pool section at hardware and big box stores or pool stores (sometimes available there in refillable containers) - it’s generally 10-12% strength & a better value than household bleach which is generally 3-6%
You would add as needed to maintain your fc above minimum for your cya at all times. Replace what is lost each day before falling too low just as you do now. Your fc demand will be no different. Maintain target range fc FC/CYA Levels
Use PoolMath to calculate amounts based on the strength you are using.

How to Chlorinate Your Pool

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