PH Questions

[Charlie Wathen]

Hi everyone,
I have 2 questions regarding PH readings:

1. Do they make a test kit, or strips, that can read higher than 8?

2. Is it better to put acid in when the water is circulating or still?

Reason for question #1 is I have a salt water pool, and I have to adjust my ph all the time. My Taylor kit only goes to 8, and I thought when it was indicating 8 I added about 1/4 of a gallon of acid and the next day it was still reading 8. So I added more until I got it down to 7.6.

Reason for question #2 is when I bought acid, the person behind the counter said would work better adding it in the deep end without the water circulating. I asked why, and he said you use less acid and it won't impact your Alkalinity.

 

[frustratedpoolmom]

Hi everyone,
I have 2 questions regarding PH readings:

1. Do they make a test kit, or strips, that can read higher than 8?

2. Is it better to put acid in when the water is circulating or still?

Reason for question #1 is I have a salt water pool, and I have to adjust my ph all the time. My Taylor kit only goes to 8, and I thought when it was indicating 8 I added about 1/4 of a gallon of acid and the next day it was still reading 8. So I added more until I got it down to 7.6.

Reason for question #2 is when I bought acid, the person behind the counter said would work better adding it in the deep end without the water circulating. I asked why, and he said you use less acid and it won't impact your Alkalinity.

1. You did the right thing, adding more to get it into range. That's all that you need to do. (What's your TA? Actually can you post a full set of results, including CYA... have you read Water Balance for SWGs in Pool School? How often are you running the SWG and at what percentage?

2. The person behind the counter doesn't know of what they speak. Always add acid with the pump running, and acid absolutely lowers both PH and Alk. Adding any chem without circulation is asking for trouble.

 

[Charlie Wathen]

FC:2.5
CC:0
pH:8
TA:120
CH: 280
CYA: 80
Salt: 3200
Phosphate: <100

have you read Water Balance for SWGs in Pool School? How often are you running the SWG and at what percentage?

No I have not.
The pump runs from 10:00am to 3:00pm. The output does vary depending on the water temperature. It normally runs at 75-80%.

 

[PaulR]

The collective wisdom in Water Balance for SWGs is that you will extend the life of your cell by running at a lower percentage, which means running it for longer each day. 5 hours seems pretty short, whether you have a SWG or not; 8 hours or more would keep the pool cleaner and let you run at a lower percentage.

I suggest you also lower your TA to make managing your pH easier. Again for SWGs the TA is better off in the 60-90 range, not 120 where you are now.
--paulr

 

[Charlie Wathen]

Thanks for the info. I'll be lowering my TA between the 60 & 90 range. As for running the pump longer, I would like to if electricity costs weren't so high (California). My electric bill in a typical summer month like August can be $500 for my 2 story house. This includes running the AC. It does make sense to lower the percent output to prolong the life of the cell.

 

[mickey4paws]

If you're not using it already, I recommend using the Pool Calculator to add the proper amount of acid: http://www.poolcalculator.com/

I agree, it's better to run your pump longer and your SWG at lower setting. I run my pump 10 hours and my output at 10 to 15%.

 

[PaulR]

I need to correct an oopsie about SWG percentages.... It seems that if you're at 100% for 5 hours, then change it to 50% for 10 hours, you haven't actually changed anything with regard to cell life (amp-hours, the percentage times the hours, hasn't changed). My mistake.

You do want to find the lowest percentage + runtime that will keep the pool properly chlorinated. If you're also looking to minimize runtime, I think it would be best to run it for a while in the early evening so you're chlorinated overnight, then run another bit during the afternoon when the sun is doing its best to burn off the chlorine.

A variable-speed or two-speed pump will help a lot with the electric bill too.
--paulr

 

[polyvue]

Do they make a test kit, or strips, that can read higher than 8?

Sure, but why bother? If you're using a drop test, such as Taylor's phenol red pH indicator that includes an acid demand reagent (R-0005), use it and follow instructions to add the right amount of MA (muriatic acid.) You don't need to know the exact pH. If you don't use a reagent to determine acid demand but your test indicates 8.0+, add enough acid to adjust pH down to the test range, wait a while, then re-test to determine the precise amount of acid needed to reach your target pH.

Comment on chlorine and CYA test result. If FC 2.5 reading is typical I'd let the CYA dissipate (by splash-out over time) until it reaches a level where the FC is at least 5% of CYA. The current 80 ppm CYA (a level encouraged by SWG manufacturers) retards the work of the chlorine. This is good, but most articles I've read say that it's too much of a good thing -- they recommend increasing the chlorine to at least 5% of CYA (5% of 80 ppm = 4 ppm chlorine); but if you are comfortable with your chlorine level, reduce CYA proportionately (50 ppm CYA, 2.5 ppm chlorine.)

As for running the pump longer, I would like to if electricity costs weren't so high (California). My electric bill in a typical summer month like August can be $500 for my 2 story house.

Amen. I tell the folks in my house that we no longer use air conditioning... but they are free to use the pool!

BTW I've learned that I can run my pump only 3 hours a day in the summer. But there a lots of variables that will determine whether you can reduce pump operation time, among which: plumbing, pipe size, number of inlets and returns, pump and filter size, GPM / PSI, size of pool, environmental contaminants, bather load, pool cover usage.

 

[duraleigh]

But there a lots of variables that will determine whether you can reduce pump operation time, among which: plumbing, pipe size, number of inlets and returns, pump and filter size, GPM / PSI, size of pool, environmental contaminants, bather load, pool cover usage.

Yeah, that's a very large "but". I'm happy that that run time is working for you but it will not work for very many pool owners so caution should be taken when reducing pump run time that drastically. 8-12 hours seems to work for most pools but some require 24/7 to get adequate filtration.

 

[polyvue]

Yeah, that's a very large "but". I'm happy that that run time is working for you but it will not work for very many pool owners so caution should be taken when reducing pump run time that drastically. 8-12 hours seems to work for most pools but some require 24/7 to get adequate filtration.

Dave, your point is well taken. 6-12 hour filter times are much more typical. My comment was not intended to disparage conventional wisdom; there's common sense and good reason to support extended filter times. This was an unanticipated personal discovery: the law of 8-12 hour (or 24/7) filtering is not written in stone! Anyway, I think it's healthy to question expert assertions, industry knowledge - as well as popular current practices.

One should be well read on the basics of pool maintenance, and diligent in testing & treating their water before jumping into the 'deep end'. But I'm sure you agree that for knowledgeable pool owners there is a lot of deep end to explore. It was Pool Forum and TFP that gave me sufficient knowledge and enabled me to resist running with the herd. At startup, my builder's pool consultant gave me a long list of products I would need for maintenance - every item in Leslie's inventory, I think, except for bleach, muriatic acid and a decent test kit!

I fully (but not mindlessly) subscribe to the advice I see posted here every day and I sincerely hope that no one will misapply my hard-won discoveries. I started my pool with 12 hours of filtering and tested twice a day... for a very long time. So, what secret unknown to everyone else did I uncover that has empowered me to reduce filtering time to 3 hours and still have clean, sparkling water?

Answer: I make incremental adjustments to treatments based on testing. I keep the pool clean, too. That's it.

I'd go back to longer filter times tomorrow if the test results indicated it -- or the water lost any of its clarity.

There's always more to learn about pools.

Greg