VS Pump speed

[KevinBond]

Last night's OCLT passed! FC remained the same: 14 (I didn't have it at the recommended 16 last night) and CC: 0.5 (probably less).

So at this point, I should just let the FC naturally drop down to recommended level? Pool math is saying between 2-7. What should I aim for and when should I turn the SWG back on?

 

[newdude]

Aim for the high end of your target, so turn the SWG on when you get there. People see the minimum, or the range between the minimum and the target range as OK. It is OK until it’s particularly hot that day, or the SWG decides to take a 2 day break, or you get a few storms in a row.. or.... or... or.....

Treat the bottom of target range as the lowest that you’ll ever want to go and we will never have this discussion again. If you are 1 or 3 above target and something happens, The worst that happens is you are in range and have plenty to spare.

 

[KevinBond]

Thanks! Once I reach 7 I'll turn on the SWG. Is there a formula or something to figure out what % I should run my SWG at or is it just sort of instinct? 2 weeks ago (before my test kit and started the slam) I just got a feel for where it would not lose or gain FC (~75% 24/7 then).

When should I begin balancing the other things (pH/TA/CYA)? Also once my FC hits the upper level of my range?

My CYA is less than 40 so I should raise it to ~60?

 

[mknauss]

Is there a formula or something to figure out what % I should run my SWG at or is it just sort of instinct?

In summer, in your climate, with CYA of 70, assume your pool will consume 3 ppm FC per day. Then with frequent testing you can adjust that as necessary.
Your SWCG in your pool will add 0.4 ppm FC when run at 100% generation for 1 hour. So come up with whatever combination of %generation and hours run to get 3 ppm FC to start you like.

 

[wireform]

I run all my pools SWCG or chlorine 2-3ppm above target. Nobody notices it and pool doesn't never gets close to the danger when something goes awry.

 

[KevinBond]

Are we ok to swim today with the chlorine this high still?

 

[jesper]

Are we ok to swim today with the chlorine this high still?

it is safe to swim up to slam level, so as long as you are below that you can swim

 

[KevinBond]

When should I begin balancing the other things (pH/TA/CYA)? Also once my FC hits the upper level of my range?

I thought I read that testing the water (other than FC) isn't reliable when slamming. Wondering at what level if FC I should start the balancing process.

 

[mknauss]

pH is unreliable at FC above 10 ppm. At reasonable FC levels (up to SLAM level with normal CYA levels) the other tests are not effected.

 

[needsajet]

No formula for SWCG, but for me, I like to use a high % so I save on electricity to run the pump. The pump runtime for me is having the surface clean when I will be either looking at the pool or swimming in it, anywhere from 3 hours in winter to 8 hours in summer. My % ranges between 50% in winter to 90% in summer. I vary the run time based on getting the water sparkly, and the SWCG % based on FC test results.

At your current 40 ppm CYA, I would shoot for 4 ppm FC. After raising CYA, I would keep my target at around 10% of CYA, but never let it go below 5%.

Bet you're glad the pump can be quiet at night now!!

 

[needsajet]

Regarding raising CYA, calculate how much is needed to raise it from your current 40 ppm up to 80 ppm, then add half that amount and test CYA again in a week's time.

 

[KevinBond]

I have some questions about lowering my TA. Before the SLAM it was 170. I lowered the pH pre-slam to 7.2. After the SLAM my pH was ~7.6/7.8 and my TA was 150.

I've now lowered my pH to ~7.0/7.2 but my TA is still 140. Should I lower my pH further or bring it back up and lower it again to try and lower the TA?

For testing TA, I've been stopping the drips as soon as the solution turns pink. Is this the correct way to do this?

 

[mknauss]

Should I lower my pH further or bring it back up and lower it again to try and lower the TA?

Allow the pH to rise to 7.6 or so and then lower to 7.2

For testing TA, I've been stopping the drips as soon as the solution turns pink. Is this the correct way to do this?

From Test Directions in Pool School --- "Continue adding drops as long as the color continues changing. The final drop, that does not change the color any further, does not count."

 

[DeanP66]

For that TA to drop quicker, you need to aerate to raise the pH. Don't just let it rise naturally because it will raise your TA some as well. Aerating will only raise pH and leave TA right where it is. Then you add muriatic acid again to lower pH back to 7.0 or 7.2 and aerate some more.

If you're already at 7.0, don't add more acid until you aerate the pool and pH goes back up to 7.4-7.6.

 

[KevinBond]

you need to aerate to raise the pH

"Aerate", this is just running my SWG/pump? My returns break the water surface. Am I good here? So basically, don't add any pH+?

 

[DeanP66]

Adding pH + will raise your TA as well, so you'll just be going in circles if your goal is to drop TA. Aerating is really the only way to get pH to rise without affecting TA.

Yes, you need to break the water surface somehow. Returns sending the water to the surface is ok, I guess, but it may take quite a while to do that. If you have a spa overflow that you can turn on or off, that could help too, but if you're running your pump at low rpms to save on electricity, you may not get much water agitation which won't help you much.

Your best best is to get some kind of device like this or make one like I did that forces water through it either through a return line, or, like me, by attaching it to a submersible pump, so you can turn it on full bore and get lots of flow and bubbles.

Something like this, which I built for under $20 from parts from Home Depot:



I use it a lot, at least 2 times a season because my fill water TA is high at 330ppm so it takes some effort to keep my TA in the 70-80 range.

 

[needsajet]

I'd just like to double check a couple things. It's unusual to have TA that high and pH that low. That said, low pH is to be expected as the FC from the SLAM is used up.

Test your fill water for TA when you get a chance, and let us know. If fill water is low, has there been any "buffer" added (aka Alkalinity Up, aka baking soda, aka sodium bicarbonate or simply "bicarb")

When you add the drops, be sure to swirl the comparator block long enough that each drop of reagent is able to fully mix with the sample. For me, I hold the comparator block in my right hand and the reagent bottle upside down in my left. I slowly squeeze the reagent bottle so that each drop fully forms before falling into the solution, while swirling the comparator block with my right hand.

Finally, how long has it been since FC dropped to a normal level, or has it finished dropping to a normal level yet?

 

[wireform]

I just take a submersible pump put it on the first or second step,plug it in and aim the geyser to the pool center. Works every time.

 

[KevinBond]

Test your fill water for TA when you get a chance, and let us know.

My hose water is 270. I retested my pool this morning and continued adding drops until the color stopped changing as described above. It is actually 160. pH looks to be 7.4/7.5 so it's come up since yesterday. Should I let it get to 7.8 then bring it down again?

If fill water is low, has there been any "buffer" added (aka Alkalinity Up, aka baking soda, aka sodium bicarbonate or simply "bicarb")

I added pH+ several weeks ago but nothing like that since.

Finally, how long has it been since FC dropped to a normal level, or has it finished dropping to a normal level yet?

I'd say yesterday it dropped to a normal level: it was 5 so I turned on my SWG. Today it is 7 (I am still adjusting).

I just take a submersible pump put it on the first or second step,plug it in and aim the geyser to the pool center. Works every time.

Can I get some more detail? Do I attach anything to the pump? Do you mean your pool steps?

 

[KevinBond]

Regarding aeration, I turned the returns in my stairs up and directed all flow to them. Creates quite a whirlpool so hopefully that will work.