Alkalinity still high - 2 years!

[P00LNerd]

2 years ago, we followed some bad advice to jack up our alkalinity, and after changing out more than 8000 gallons of water plus draining down the random rain, we're still holding 110 ppm.

Our pH is also trending low, which I know can be easily fixed with aeration, except the pool is already running 64F and aerating in cold weather ain't going to help that. In other words, I'll do it if I need to, but I suspect effectiveness of this method at these temperatures may be reduced, and it's going to make our pool even colder when we're running 40F nights. Right now, I have the solar cover on, and I'm actually seeing a few degrees temperature increase with each sunny.

Can you guys have a quick peak at my water test, and let me know what you'd do? You can ignore the low salt, I just got 3500 gallons fresh water added yesterday, which knocked it down from 3200 to 2500 ppm. I just added 80 lb. of salt to bring it back up a bit, but am waiting until tomorrow to re-check salt content.

 

[Newdude]

let me know what you'd do

Ask a dozen folks this one and get a dozen opinions. Thats said I'd let the 110 be. I rarely see the need to force TA down. The way I see it, if you go out of your way to speed up the Ph cycles to lower the TA, you still have to manage the Ph for the time it would have taken for the TA to fall on its own. But its personal preference if you'd rather have to add acid a little more often while the TA does its thing, or do more work now and a little less work between A and B for probably the same total work in the end.

Only use the 10s for CYA. We round up anyway so its way easier to know its not a 30 or 50 so its a 40.

 

[PoolStored]

You need to maintain your FC higher. We don't want no algae.
Your CYA is 50, always round up to the next 10.
Chlorinate for 50.
Always follow this...Link-->FC/CYA Levels
Turn that SWG up and maintain the top of the range for your CYA.
Don't worry about TA. Just manage your pH.

 

[sduda210]

Have you tested your fill water for alkalinity? Some people have high alkalinity right out of their hose. A high alkalinity just means you'll have faster pH rise. I basically have no pH rise when I keep my alkalinity in the 60-70 range but that's probably due to the slightly acidic rain and the pH of my fill water being at 5.9.

 

[P00LNerd]

Only use the 10s for CYA. We round up anyway so its way easier to know its not a 30 or 50 so its a 40.

Cool. I know my CYA is low, which I never worried much about with SWG, it maintains near-constant FC whether CYA is low or not.

But if adding CYA also brings Alkalinity down, whether absolutely necessary or not, I guess it can't be a bad thing.

You need to maintain your FC higher. We don't want no algae.

Pool math indicates I'm right at the geometric mean of the ideal range of 2.0 - 8.0.

Your CYA is 50, always round up to the next 10.
Chlorinate for 50.

I changed CYA to 50 in Pool Math, but it still indicates my FC is right in the middle of the ideal range of 2.0 - 8.0.

Always follow this...Link-->FC/CYA Levels

Checked, also reports 2.0 as min and 3 - 8 as ideal.

Turn that SWG up and maintain the top of the range for your CYA.

Why top of range? Isn't anywhere in range good, with lower being generally better for equipment?

Don't worry about TA. Just manage your pH.

Got it.

Have you tested your fill water for alkalinity? Some people have high alkalinity right out of their hose. A high alkalinity just means you'll have faster pH rise. I basically have no pH rise when I keep my alkalinity in the 60-70 range but that's probably due to the slightly acidic rain and the pH of my fill water being at 5.9.

Fill water comes from a trucking company, they dump 3500 gallons into the pool in all of 5 minutes, so there's really no opportunity to test it. But by comparing test results before/after, I guess I could extract the properties of the fill water.

 

[Newdude]

Pool math indicates I'm right at the geometric mean of the ideal range of 2.0 - 8.0.

With little room for error. The big rains the last few days shut my SWG off for 12 hours twice. If the AM self check was the bad one, my FC would swing like a LC pool that day.

Its best with SWGs to keep at least a one day buffer over min FC for whatever curveballs hit today.

There's no prizes for being 'mid range' or whatnot. Minimum is to be avoided at all costs. Thats 100% of the mission. Poolmath reports minimum (2) to high target (8) and its mostly irrelevant. That doesn't factor your climate or time of season. July in Miami is way different than October in Michagan. Or even just July at both places

Its still early in the season right now with minimal loss, but we'll be playing for keeps soon.

 

[PoolStored]

Why top of range? Isn't anywhere in range good, with lower being generally better for equipment?

For when you have a high demand day. Keep it around 8. Pool, people and equipment are safe up to SLAM level.

 

[P00LNerd]

Cool. Got it! Will let it raise.

But for now, temperature is too low for swimming and solar cover is on 24/7, so I expect FC loss is probably under 0.5 ppm/day. Last time I ran the SWG under these conditions, I found myself having to toggle between turning it off and running at min setting, just to avoid going over range.

 

[PoolStored]

Yeah, might have to toggle, just keep it at the top of the range.

 

[Newdude]

You say 'over range', I say 'not hitting minimum FC today'

Potato..... pahtahto.

 

[P00LNerd]

Other than about 2 weeks in July when we leave it off, we tend to keep the solar cover on all but a few hours each afternoon. We like to keep the pool around 86-87F, and that would require a lot of heater run-time if the solar cover were left off overnight and mornings.

The result of this is that I've actually gone with zero added chlorine for days at a time, and never fallen out of range, in fact our losses can be less than 0.2 ppm.

Interesting note, I just looked up that we closed Oct.26 @ 11.5 FC, and opened May 3 @ 6.0 FC. That's 0.029 ppm/day!

 

[Newdude]

And one heckuva OCLT. You lost 1ppm a *month* James coined it the OWCLT for over winter chlorine loss test.

 

[P00LNerd]

Cover is the opaque tarp type, which I'm sure is the major factor. But also, we're seeing regular overnights at the freezing mark by Oct.26 when I closed, so cold water was probably another factor.

IIRC, I covered the pool around Aug. 28, as the kids were back in school and it was already too cold to swim by then. But I left the pump and chlorinator run until Oct.26, when I drained the water below the skimmer and lights and blew the lines dry.