Where to start with balancing water?

[briangreul]

I'm trying to get a handle on my pool water and have read the "pool school" stuff. I know the water is off balance, but I'm not sure which parameter to try and move first. I'd like some suggestions/feedback.

Current readings: (I created a spreadsheet for these for now)
FC 2
CC 2.5
TC 4.5
CH 700
TA 175
CYA ?? (historically this has been high, but I've been off tablet crack for a while) ( I did not get a tube with my test kit and I've sent an email about that. For now I think there are actionable steps I can take)
PH (meter) 7.8. (calibrated using RO water that should have about 10 ppm TDS)
CL (visual) 3
PH (visual) 7.8

I bought the TF Test kit and this was my first run through with it.
I want to SLAM the pool, but I think I need to get the balance under control first. I have an Algae crop. I nearly had the algae under control and I went out of town for a week and one of the connector hoses popped off the booster pump. No telling if it was 2 or 6 days that the pool didn't do much. Just lucky I didn't burn up any pumps with that fiasco. The Algae got vicious. I resorted to 2 pounds of powdered shock and another 2 pounds the next day and that got rid of the green tint in the water... but it's still a mess.

I also have some Clorox Algaecide in the pool. It's copper based which should be compatible with the SWG. It just doesn't seem to be working this year.
Historically nitrites/nitrates have been an issue according to water tests done by Leslie's Pool Chemical Sales Store. The culprit there are leaves and my yard guy. Yard guy has gotten better about not letting clippings get in the pool. We also have "surface" water here which is naturally spiked with nitrates/nitrites. My water bill is already in "Oh my Gosh" territory so I'm not quite ready to drain/fill or RO the water that goes to it.

My thought is that the PH needs to move first and that requires acid. I have no idea how much, but my thinking is that it's going to take a couple gallons. At the first gallon I can check the reading and see where I'm at and then reverse calculate the water volume to get a better idea of my actual pool volume. Over time with a few similar readings I should have a good idea of the actual pool capacity.

 

[Texas Splash]

I want to SLAM the pool, but I think I need to get the balance under control first.

CYA. That's it. Other than lowering the pH to about 7.2 first, confirming an accurate CYA is critical so that you know what elevated FC (SLAM) level to match as noted on the FC/CYA Levels. When you go to increase the FC, use liquid chlorine (or regular bleach) only. Avoid algaecides (especially copper) as they will do nothing to kill algae and only consume chlorine. Follow the SLAM Process carefully and you can't go wrong.

Be sure to sign up for our PoolMath APP and go to the "Effects of Adding" to determine how much of any chemical is required to meet you goals. If you have any questions just let us know.

 

[Texas Splash]

Until you get the viewing tube to perform the CYA test, just add about 1/2 - 3/4 of a gallon of chlorine to the water each day to keep algae form getting much worse.

About the missing CYA viewing tube, I'll tag @Sarah and Nate just to be safer and ensure they received your email.

 

[briangreul]

Until you get the viewing tube to perform the CYA test, just add about 1/2 - 3/4 of a gallon of chlorine to the water each day to keep algae form getting much worse.

About the missing CYA viewing tube, I'll tag @Sarah and Nate just to be safer and ensure they received your email.

I realized that the "tube" was actually the little squeeze bottle I had been using as a pipette. lol.
The CYA was at the high end of acceptable for a long time (tablet chlorine)... when I went SWG I decided I would let it burn off as opposed to draining/filling my pool.
I have some test strips and they suggest it's normal, but I don't like/trust the test strips.

Why would I add liquid chlorine when the chlorine numbers suggest the SWG is working and the level is okay other than not being very effective due to the high PH.

 

[Texas Splash]

Why would I add liquid chlorine when the chlorine numbers suggest the SWG is working and the level is okay other than not being very effective due to the high PH.

You mentioned earlier that you had algae and the pool was a mess. It didn't appear that you had a proper test kit at the time which would make it impossible to perform a SLAM Process properly. As such, you could very-well have residual algae still lurking in the water, even though your SWG appears to be holding its own. Now that you have the proper tools, if you doubt you have algae, at the very least I would perform an Overnight Chlorine Loss Test (SWG OFF) to be sure. If you pass the OCLT, then all is good and you can resume normal balancing.

In your numbers above, there are 4 red flags:
1 - Very low FC level
2 - Elevated CC level (over 0.5)
3 - Unknown CYA
4- Elevated CH

Your next step will be driven based on your CYA result. We really need to know that number.

 

[briangreul]

I ran the CYA test and it's over 100... Assuming it's a linear scale I'd guess 130. I'm just going to record it as 100+
I went and looked at the shock I used and it does not list any CYA or make mention of it.... but I'd be surprised if it did not have any.
I might have to drain/fill. Ugh. I suppose in the process I could scrub the algae out and patch up the one bit of plaster that is in really sorry shape.
I have never been down to the bottom to remove the cover and see if there is a proper hydrostatic fill valve. I'm not hopeful. I do scuba dive, so I have no issues putting on a mask and going down there, but I have a low confidence that it will be correct and I don't want the pool to pop out on me if I drain it..... although that would end the problem in a different way.

Based on what I know about CYA/FC/PH there is no way it would pass an OCLT right now.
At a minimum I think a partial drain/fill is in order.... which should help with both PH and CYA. Depending on what's at the bottom of the pool it might need to be done a few times at a more shallow level. I just hate $400+ water bills. Between the sprinklers and the pool ..... grrrrrrrr.

 

[mknauss]

CYA is not linear in the test. It is logarithmic. Do the dilute test. Cut the pool water with tap water 1:1. Us that mix for the pool water in the test. Double the results.

You can exchange water instead of drain. See Draining - Further Reading

 

[Texas Splash]

At a minimum I think a partial drain/fill is in order.... which should help with both PH and CYA.

And the CH.

 

[briangreul]

CYA is not linear in the test. It is logarithmic. Do the dilute test. Cut the pool water with tap water 1:1. Us that mix for the pool water in the test. Double the results.

You can exchange water instead of drain. See Draining - Further Reading

Any reason to use tap water (icky) when I have RO water available? RO water should be chlorine/chloramine free and TDS of around 10-12 ppm. I don't currently have the DI module on-line in the system so that's the best water I can make right now. I also have a very large saltwater aquarium that is currently not active.... another item on my to-do list. The side benefit is that I have a very nice water filtration system for it.

I just read about the dilution test in another thread, so I'll do that next time I test. I think for the moment I'm going to plot my next steps and retest tomorrow and see where my numbers are at.
It's also worth pointing out that this month is the end of my pool season anyway. I don't like cool water and despise cold water. So post September I don't even consider getting in the pool unless I'm wearing a wetsuit. It doesn't usually freeze here so we don't drain the pool, we just stop using it unless we have a heater.

Aside from a zero algae goal, I'm not really losing anything with the pool in it's current condition. I don't use it much beyond enjoying the pretty water at night.
I eventually see a SLAM as necessary to conquer the algae and that's going to create issues with the current filter setup.

 

[mknauss]

Not sure what the SLAM Process has to do with filter.

Take care.

 

[Texas Splash]

Aside from a zero algae goal, I'm not really losing anything with the pool in it's current condition. I don't use it much beyond enjoying the pretty water at night.

Same here. Oct is about our last swim month until Apr/May. I'm spoiled in that I like 87 degree or above water. But if you can somehow get the CYA down to at least 70-80, then you will not only be able to balance the FC better, but some of it will go away over the winter and might leave you with a very good starting CYA next season. How you elect to lower the CYA/CH is up to you, but typically a water exchange is most convenient. Certainly your call though. Also remember that when your FC is maintained over 10 ppm, which is common when the CYA is over 100, your pH will read high.

 

[briangreul]

Not sure what the SLAM Process has to do with filter.

Take care.

My understanding is SLAM process involves elevated chlorine and scrubbing the algae out. Algae suspended in the water will clog the cartridge filter pretty quickly. Last time I scrubbed Algae it was so bad I had to clean the filter every 2 hours.

Did I miss something that involves Unicorns and Kittens removing the algae so my filter doesn't have to?

 

[briangreul]

Same here. Oct is about our last swim month until Apr/May. I'm spoiled in that I like 87 degree or above water. But if you can somehow get the CYA down to at least 70-80, then you will not only be able to balance the FC better, but some of it will go away over the winter and might leave you with a very good starting CYA next season. How you elect to lower the CYA/CH is up to you, but typically a water exchange is most convenient. Certainly your call though. Also remember that when your FC is maintained over 10 ppm, which is common when the CYA is over 100, your pH will read high.

Yea, I think I want to tackle the filter as part of addressing the water quality. It's really not workable for me to scrub the algae and have to fight the cartridge non-stop (every 2 hours).
Like you, I like the water in the pool warm. I suspect a partial change will help with the CYA, but I want to investigate the main drain before I mess with it.

 

[reggiehammond]

My understanding is SLAM process involves elevated chlorine and scrubbing the algae out. Algae suspended in the water will clog the cartridge filter pretty quickly. Last time I scrubbed Algae it was so bad I had to clean the filter every 2 hours.

Did I miss something that involves Unicorns and Kittens removing the algae so my filter doesn't have to?

Your filter only removes the dead algae once you've killed it - if you continue to let things be, you're just increasing the amount of algae you'll eventually need to filter.

You'll need to manage filter pressure to get the junk that's in your pool, out. But with a cartridge filter, that's not very difficult. You could start with a clean filter, then watch pressure.

Up to you when you want to deal with it - but I'd begin trading the bad water for good and get a good handle on it now. The SLAM process is tried and true and doesn't require a lot of fuss.

 

[briangreul]

Your filter only removes the dead algae once you've killed it - if you continue to let things be, you're just increasing the amount of algae you'll eventually need to filter.

You'll need to manage filter pressure to get the junk that's in your pool, out. But with a cartridge filter, that's not very difficult. You could start with a clean filter, then watch pressure.

Up to you when you want to deal with it - but I'd begin trading the bad water for good and get a good handle on it now. The SLAM process is tried and true and doesn't require a lot of fuss.

With DE it's easy enough to backwash and recharge. With a cartridge filter you have to clean the filter. Whether you start with new or not it's still going to clog when you scrub the algae out. It does not have to be done today and there isn't any rush to it.

 

[reggiehammond]

With DE it's easy enough to backwash and recharge. With a cartridge filter you have to clean the filter. Whether you start with new or not it's still going to clog when you scrub the algae out. It does not have to be done today and there isn't any rush to it.

I don't backwash my DE - just clean it twice a year or so. I can pull the ring, rinse the cartridges with a filter flosser, and have it cleaned up and running in ~15 minutes.

My question is why not take care of the algae early, rather than let it get a hold and proliferate?

 

[briangreul]

I don't backwash my DE - just clean it twice a year or so. I can pull the ring, rinse the cartridges with a filter flosser, and have it cleaned up and running in ~15 minutes.

My question is why not take care of the algae early, rather than let it get a hold and proliferate?

Yea it would be nice to take care of the Algae early.... but that horse left the ranch. There is an algae problem and getting rid of it will not be an overnight activity.
The current "burn rate" on cartridges is about 6 to 10 weeks this year. The filter is probably sized correctly, but with the algae problem it still eats cartridges.
I've had 3 DE filters. One was a Hayward that was trash. The other two were over-sized Pentair units. I don't remember the exact size. One came with the house and needed all new internals, a new backwash valve and the tank was shedding fibers. A friend of mine had a NOS unit that I picked up for $100 so that was a no brainer to replace it. The DE filter worked fine, but the second one developed a leak somewhere and I didn't enjoy taking it apart, trying to replace bits and putting it back together again. Towards the end of it's life it was letting some DE get back to the pool. When we had the "big freeze" the valve for backwashing got cracked and I decided to axe the DE filter as opposed to buying new filter grids and a new valve. I used to backwash when the pressure gauge indicated it and could get by with doing it 2 or 3x year.

The cartridge filter delivers almost as good of water quality as the DE filter. However, cleaning the cartridges is a PITA. It never seems to really get them clean although it will prolong their functional life. I liked being able to backwash the DE filter. If the cartridge filter was oversized it might not be as big of a problem. But it's not, and I don't think it makes sense to buy another one.

To get this pool straightened out I'm going to have to change some (or all) of the water and then SLAM it until the algae is gone. During that process I'll burn at least one, maybe 2 or 3 cartridge filters. It seems like that will make a nice dent in the cost of a Sand Filter at $60/cartridge. As a bonus I'll be able to backwash the Sand Filter and I read elsewhere on TFP that if I add a little DE (1/4 cup at a time) I can get some better filtering from the sand filter if I want it.
The moderating factor on the water change is going to be what's in the main drain. I have no idea if there is a hydrostatic valve there or not. Have never taken the cover off to look. If there is not one, or I don't trust what's there it will be partial water changes to avoid the pool floating. Water table here is quite high and I have low confidence in the pool construction based on other issues I've had to iron out with it. I've been battling Algae hard since late June. I almost had it dealt with in July, and then in August it revolted while I was out of town.

I invested in the TF Test Kit and that's the first step. I feel like I actually know WTH is going on with the water now. I knew there was a problem, I just couldn't quantify it before. It seemed like the SWG could never make enough chlorine, which is true with a high cya and PH.

At any rate, I don't like the idea of spending $200 on cartridges when that will go a decent way towards buying a sand filter. I'm already looking at $200 to $500 in water to do the changes. Our water here used to be really cheap and it's not anymore. I had a $100 bill for 5K gallons this month. The other variable is how much/little it rains... if it doesn't rain my $prinkler$ will run.
With all of that in mind, waiting another few days or a week and taking a few more readings isn't going to swing the needle on this pool.

It will however, give me time to plan out what I want to do and not have to buy 4 cartridges before I put in a sand filter and change the water 3x.

 

[reggiehammond]

You can’t just rinse your cartridges and return to service? I’m confused why you need to replace; they’re typically easily reusable provided you don’t add any magic potions to the pool.

Good luck with it all.

 

[briangreul]

You can’t just rinse your cartridges and return to service? I’m confused why you need to replace; they’re typically easily reusable provided you don’t add any magic potions to the pool.

Good luck with it all.

It will help a little, but then a week later I'm right back in the same spot. Less if I'm scrubbing anything. A fresh cartridge I'll get a month out of.
I checked and the filter is good for 2.5x what I think the volume of the pool is. I even bought a hose attachment for spraying the filter out. That helped tremendously... but it's still a PITA compared to backwashing.

I did some free diving this afternoon. I have a plug in my main drain. I posted in the equipment section to get some feedback before I contemplate draining. I'm being cautious as I've never drained this pool and am not quite ready to get rid of it.

 

[briangreul]

I also measured my pool, it's sort of a rectangle with half moons at the ends... nothing magical.
Currently carpeted with algae on 2.5 sides and dusted on the bottom. It's less than a week of no circulation from being a frog pond.
The algae looks greenish-yellow and I would guess it's mustard algae if I was going to pick something.
14'9"x29'10", 3' at the shallow end and 6' at the main drain. Should be somewhere between 12K and 15K, but still not a very big pool.