Do I always need to slam a pool after a bad rain

[tuxedy]

Hi all. Weather is calling for rain every day with thunderstorms, my pool gained about an inch but it turned dark green (not very cloudy though)- I had just slammed the pool last week and it was beautiful
Last night I dosed FC to 5

4:00pm
ph: 7.3
CYA: less than 30 - maybe like 20?
CH: 825
TA: 40
FC: 4

it rained yesterday and the pool was green this morning. I decided to run my sand filter for 8 hours in a row (I usually only run 3 hours in the day and 2 at night) to see if that would help, it did improve a lot. When the pool is very healthy it only loses 1-1.5 FC per day (not much swimming these days) - we get 12hours of sun but it's only 72-75 outside. Now its getting better, but still that nagging slight teal color which in the past would lead to more and more cloudiness that I had to slam out (that was from excess sunscreen and kids)

So pool appears healthy, no major FC loss, should I just run my pump until it clears all (which can take a while) or should I just slam it again... we are in rainy season in Rwanda, so it could torrentially rain at times throughout the next month...

Also does it help to run the pump during heavy rainstorm?

PS: I have not found CYA level of 60 or 20 to make a huge difference on my FC loss per day. Interestingly, it seems like FC loss per day is improved at a lower CYA ... I prefer to slam at lower levels anyways. I have historically kept my FC to CYA ratio properly.

 

[Jimrahbe]

T,

You should never have to SLAM a pool after a hard rain.. If you do, you are not keeping your FC at the TFP recommended levels, or you never got rid of the original algae.

Thanks,

Jim R.

 

[wireform]

You can also take advantage of the fresh rain water to lower your CH by lowering the water level before heavy rain.

 

[Newdude]

I decided to run my sand filter for 8 hours in a row (I usually only run 3 hours in the day and 2 at night) to see if that would help, it did improve a lot.

^^^^^^^ this. If your FC is in range when weather hits, it can only affect you by the appropriate %. 2 inches of rain in a 60 inch average depth pool is about 3% and you'd never see FC loss from 6(?) To 5.82. (Insert actual #s here)

Now. If those 2 inches of 0 FC water had 12 hours to fester in the sunlight before the pump mixed the cold/stratified rain water on top...... it may overwhelm the FC you had.

Whenever you see a storm coming, make sure you have some insurance FC and run the pump every couple of hours to keep it mixed. If a pop up storm happens randomly, mix ar your earliest convenience.

 

[Mdragger88]

Green/cloudy = not crystal clear = SLAM Process time
To be clear - this is not a one time addition of liquid chlorine.
It is reaching Shock Level AND Maintaining that level until u pass ALL 3 end of slam criteria:

You are done when:​

• CC is 0.5 or lower;
• You pass an Overnight Chlorine Loss Test (shows a loss of 1.0 ppm or less);
• And the water is clear. I suspect as Jim said - you either ran your fc too low or you weren’t actually completely done with the last slam -follow the FC/CYA Levels

 

[Mdragger88]

Another thing to check is that your chlorine is the potency you believe it to be. Test 30minutes after adding next time to confirm you achieved your goal & adjust your dose as necessary if your bleach is weaker.

 

[tuxedy]

I understand all the slam criteria and have done so multiple times (on average I seem to get about 6 weeks of crystal clear pool and keeping my FC at the right value, never allowing it to drop below the minimum). It just seems that I need to slam more often than I'd like to. If I were following "shock" rules of other owners who shock weekly or every time there is a group of people swimming, I wouldn't be surprised. I just thought that trying to maintain to such a degree of precision that I have and following to the tee the suggestions here on the site would warrant less times needed to SLAM. I just feel a bit defeated that I got it recently in really good shape and just a week later I'm dealing with a green pool again from a bad thunderstorm.

So, yes it rained all night long and in the morning first thing I did was run the pump. Pool is still green color, slightly cloudy. I think I might just let this one try to bounce back on its own as long as I am not consuming too much chlorine during the days.

Does Green always mean something organic in the pool? Could it simply be contaminants? There didn't seem to be any water running into the pool.

 

[Newdude]

Perform an Overnight Chlorine Loss Test to rule out algae. I know. I know. Just humor me though. If it passes then take a sample to the pool.store for a metals test. Copper/ iron may make you go green at times with otherwise good chemistry.

 

[Mdragger88]

After the oclt tells the tale - Also check all your nooks & crannies for hidden algae. Ladder rails, light niches, drain covers, water features, skimmer throats etc.
if u pass the oclt it could be a metals issue. can u post a pic of the green? Is it cloudy or clear? Often times metals will make it go green when u raise the fc level but it will be pretty clear - just the wrong color

 

[tuxedy]

Didn't get a chance to do a OCLT yesterday. But the pool has remained a reasonably clear teal green shade. It monsooned here for 20 minutes yesterday, and again it's raining a bit this week.

Does anyone have any problem of pool paint that bubbles and then pops a bit but remains on the pool surface? Our pool paint is a year old and it bubbled up a month after painting, and then it's continuously been increasing in places near the tile line skim line. I wonder if algae can hide in those places because I can't brush those well.