Testing and balancing water or backwashing first

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
Hello! I'm still new and still learning how to take care of our new built pool from last December 2019. 11

Temp 76°
FC: 3.5
CYA: 85-90
TA: 80
pH: 7.5
CH: 350

I added a little over 40oz. of 12.5% liquid chlorine after test to try to get FC level up to recommended amount 7ppm. No more tablets being used.

How often should I do all my tests again and adjusting chemicals? Also, when should I perform backwashing ...before tests and balancing water or wait for another time? I have read some articles recommending weekly backwash. While other articles recommend every 4-6 weeks or when psi increase by 10psi (I've never seen our pool raised by 10psi). The pool was built last December 2019. I don't have a lot of trees or leaves around. PSI rarely raises (actually I have not seen it raise much maybe just 1 or 2 psi) over a month. Should I just backwash on some kind of set schedule anyway even if psi has not increased much?

Thank you.
 

Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Right now, you still want to test the FC and pH daily. The TA weekly, and the CYA and CH about monthly if there were no large water changes. You'll backwash when the filter pressure increase by 25% from the clean pressure. Remember that as your water gets colder, the FC will not drop as much or nearly as fast. So here shortly you may only need to test the FC and pH every 2-4 days or so. You'll see a pattern. Hope that helps.

Also see:

 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,494
Bedford, TX
I have read some articles recommending weekly backwash.
H,

Anyone that backwashes weekly has serious mental issues... :mrgreen:

What type of filter do you have??? DE or Sand?

I noticed that your CYA is 90 and you do not have a saltwater pool.. This means your FC is way too low.. See this chart FC/CYA Chart

Just for reference I have two pools with DE filters and never backwash any more... I just open and clean the filters about every 6 months.. I'm not saying that you should do this, but it gives you an idea how silly it is to backwash every week.. Keep in mind that the PSI reading is very dependent on the pump speed. Since you have a VS pump, if it is running at a low RPM (which it should) then your PSI will be very low and it will be hard to determine small increases..

If I were in your shoes, I would drain enough water to get your CYA under 50.. and then start to get your pool water balanced.

Thanks,

Jim R.
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
Thanks Jim on backwash info. I have DE filter and it is good to know you don't really need to backwash much, if any at all. I guess I'm at the very minimum according to that chart. I can test again and add more tomorrow.

Oh! I just did a water exchanged two days ago to dilute the CYA level from 135CYA down, and was able to only get it to about 85-90CYA level.using the water exchange method from TFP. I was hoping it would be lower than that ( I'm just glad it lowered and I know it brought it down some). If you're curious, I used submerge pump with garden hose pump of 5gallon/min. I ran the exchange for 27 hours with my calculation to remove 2/3 + 10% of pool volume. I think I'll be leaving that level there for now and monitor throughout the fall and winter and see how it goes.
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,732
Prosper, TX (DFW)
If you have stopped using pucks and have already drained, a CYA of 90 is manageable and will hopefully drift down some before next swim season. You just have to be willing to keep your FC at 10-12 until then.

As for the backwashing, the more traditional method for a DE filter is to backwash when your filter pressure rises 10% from your clean pressure. I do mine every 6 weeks or so, which is usually before I have hit the 10% mark but I can see slight changes in the flow so I go ahead and do it. Weekly would be crazy and really unnecessary unless you had an algae bloom or something else causing it to clog

I did take apart the grids as Jim describes once in my 12 months of pool ownership. This was a lot more labor intensive, but is a much deeper clean. I plan to backwash as described above (~15 min job) and do the deep clean annually (~1 hour, probably less once you have done it a few times).
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,494
Bedford, TX
deep clean annually (~1 hour, probably less once you have done it a few times).
JJ,

The very first time I took a DE filter apart, it took me a couple of hours to get the grids back together.. I came within a few seconds of just giving up, and almost cried... ☹

But then, just like magic, everything lined up and fell into place.. I'm pretty good at it now, but the first time was a killer for me. :mrgreen:

Did you mean 10% or 10 PSI? 10% is not much.. We use a 25% increase as our standard here at TFP.. But that covers all kinds of pools, filters, and plumbing, so to me, it makes sense to learn how your pool works, and use what makes sense to you..

Thanks,

Jim R.
 
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Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
Mine starts at 10 psi so if 10% more or even 25% it's only between 11-12.5psi. I guess that does sound like about between 6 weeks for me, too then. I haven't tempted to open up the big DE filter....it's massive for me! Maybe, I'll have my husband try, but he's leaving the pool up to me to take care of, except heavy stuff.

I already got the filter clean twice by pool maintenance guys within 6 months of pool built (once in april and another second one end of June because i think some rocks or gunite got into the skimmer pipe). Should I do one at the end of the year or should I just wait til next spring before swim season?

Sorry, back to my silly question. Can I add other chemicals to balance water right after backwashing and adding DE?
 

Newdude

Well-known member
Jun 16, 2019
4,585
NY
Hey Hachu !!
Mine starts at 10 psi so if 10% more or even 25% it's only between 11-12.5psi
whenever you start fresh use a high RPM as a baseline to get that PSI. Then run your normal schedule. Whenever you want to test, go back to the same high RPM and it’s much easier to see the difference between 20 and 25 instead of 10 and 12. A lot of us have a single digit on low speed and it’s nearly impossible to see the rise at 3/4/5 PSI.
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
19,494
Bedford, TX
Sorry, back to my silly question. Can I add other chemicals to balance water right after backwashing and adding DE?
H,

The first thing to do after backwashing is to add 80% of the DE your filter takes when clean..

After that, you can add all the chemicals you want.. The first thing I would add is the chlorine you need based upon your CYA level and then adjust the pH as necessary to be somewhere in the 7's...

Thanks,

Jim R.
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
Hey Hachu !!

whenever you start fresh use a high RPM as a baseline to get that PSI. Then run your normal schedule. Whenever you want to test, go back to the same high RPM and it’s much easier to see the difference between 20 and 25 instead of 10 and 12. A lot of us have a single digit on low speed and it’s nearly impossible to see the rise at 3/4/5 PSI.

I dont understand the high RPM. Where to I check it and change that? I haven't really want to change any numbers in my iAqualink app that were set by the pool builder.
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
H,

The first thing to do after backwashing is to add 80% of the DE your filter takes when clean..

After that, you can add all the chemicals you want.. The first thing I would add is the chlorine you need based upon your CYA level and then adjust the pH as necessary to be somewhere in the 7's...

Thanks,

Jim R.

I just did another test and here are the results...

Temp: 77°
pH: 7.8
FC: 4.8
TA: 80
CYA: 75

How long should I wait in between before adding the second (muratic acid) to lower pH?

Thanks :)
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,732
Prosper, TX (DFW)
I would wait until your pH is 8 before knocking it back down to ~7.5 to save yourself some headache.

What I absolutely would do right now is add chlorine. For a CYA of 80, you should be 9-11 and never ever ever below 6. You are currently at 4.8. See the FC/CYA chart in my signature if you need help.
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
I would wait until your pH is 8 before knocking it back down to ~7.5 to save yourself some headache.

What I absolutely would do right now is add chlorine. For a CYA of 80, you should be 9-11 and never ever ever below 6. You are currently at 4.8. See the FC/CYA chart in my signature if you need help.
Does Chlorine raise pH level? I will leave mine as is if it doesn't make much difference in raising the pH.

How do I view your signature? I haven't been able to view anyone's signature. If the CYA level is from TFP then yes, I got mine saved so I can go back to adjust as necessary. I read an article and thought 7.5% was good, but that was the minimum. Still learning :)
 

Newdude

Well-known member
Jun 16, 2019
4,585
NY
I dont understand the high RPM. Where to I check it and change that? I haven't really want to change any numbers in my iAqualink app that were set by the pool builder.
Can you select different speeds through the app ? Maybe a preset for skimming that turns It up high ? Or is it a lower speed all the time ?
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
Can you select different speeds through the app ? Maybe a preset for skimming that turns It up high ? Or is it a lower speed all the time ?
I haven't gotten the chance to learn iAqualink yet. I'm not sure where to start. I may need to find the manual or is there a place where I can learn about setting variable speed on iAqualink? I can attach a few screenshot of what I got.
 

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Newdude

Well-known member
Jun 16, 2019
4,585
NY
That looks like you have lots of options but we need an aqua link user/pro. I don’t have any automation so you already know more than me. :)

You’ll want to run the pump at 3000+ RPMs, and go check the psi. It will be a considerably higher than 10 and easier to tell it went up. For example 22. Anytime you want to check to see if the filter needs cleaning, go back to that exact high RPM and use the 22 X 25%. And clean the filter at 27.5(ish) if it gets that high. If not you don’t need cleaning. 22 to 27 is much easier to spot at quick glance than 10 to 12. The needle itself may be 2 psi thick.

as soon as your done checking the psi, return the pump to it’s normal setup.
 

Hachu

Bronze Supporter
Aug 11, 2020
45
Dallas, TX
That looks like you have lots of options but we need an aqua link user/pro. I don’t have any automation so you already know more than me. :)

You’ll want to run the pump at 3000+ RPMs, and go check the psi. It will be a considerably higher than 10 and easier to tell it went up. For example 22. Anytime you want to check to see if the filter needs cleaning, go back to that exact high RPM and use the 22 X 25%. And clean the filter at 27.5(ish) if it gets that high. If not you don’t need cleaning. 22 to 27 is much easier to spot at quick glance than 10 to 12. The needle itself may be 2 psi thick.

as soon as your done checking the psi, return the pump to it’s normal setup.
[/QUOTE

When pump first turn on the pump, I see it at 18psi then it goes down to 10pso. I'm guessing, that's when it primes and at highest or higher speed?
 

JJ_Tex

Bronze Supporter
Jul 17, 2019
1,732
Prosper, TX (DFW)
Does Chlorine raise pH level? I will leave mine as is if it doesn't make much difference in raising the pH.

How do I view your signature? I haven't been able to view anyone's signature. If the CYA level is from TFP then yes, I got mine saved so I can go back to adjust as necessary. I read an article and thought 7.5% was good, but that was the minimum. Still learning :)
1. Chlorine doesnt raise pH level.

2. I'm guessing you are viewing this on your phone. Turn it sideways and you should be able to see the signatures.

3. Totally fine to use your prime speed when checking your filter PSI. Just make sure you are consistent on what speed you are using to check your clean vs dirty pressure.
 
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Newdude

Well-known member
Jun 16, 2019
4,585
NY
When pump first turn on the pump, I see it at 18psi then it goes down to 10pso. I'm guessing, that's when it primes and at highest or higher speed
Exactly. You just need to figure out a way to do it on demand. You can probably just shut the pump off, then back on and have plenty of time to watch the prime PSI as your baseline. Then you wont have to mess with the settings. And if 18 is the clean filter PSI after you do it next, your clean to dirty range is 18-22.5. Still a much easier quick read than 10-12.
 
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