Rain water

newguyjosh

Well-known member
Jun 6, 2010
92
Central Indiana
What effect does rainwater have on my pool? It is still a little low, should I allow it to fill up with rain (gotta be better then my well water right?) or is rain water bad for the pool? I guess I dont know if I should keep the cover on or off during rainy days
 

257WbyMag

TFP Expert
LifeTime Supporter
Feb 23, 2008
5,061
Denton, TX
poolgirl22 said:
Its free for me.
That makes it perfect.
:mrgreen:
I'm with you there! :goodjob:

Rain typically has very little effect on things as it is fairly inert. If anything, it tends to aerate a little bit (pH goes up slightly). The biggest problem for people if they get lots of rain and don't have enough chlorine. Rain does carry a goodly amount of organic contaminants and so FC can go down pretty quick. Left unchecked, you can get algae in short order. But if you maintain your pool well and keep the FC at target, you'll be alright.

If I see rain coming on the radar, I will often bump the FC a tad before it makes it to me. But then, I'm a geek like that. :mrgreen:
 

257WbyMag

TFP Expert
LifeTime Supporter
Feb 23, 2008
5,061
Denton, TX
primetime said:
If I need to back flush, I do so after a big rain when my pool is over filled. Saves me $$$ on adding water.
Yep, that's a good time to take advantage of a situation like that.
 

poolgirl22

Platinum Supporter
LifeTime Supporter
Apr 14, 2010
595
Stephens City, VA
257WbyMag said:
poolgirl22 said:
Its free for me.
That makes it perfect.
:mrgreen:
I'm with you there! :goodjob:

Rain typically has very little effect on things as it is fairly inert. If anything, it tends to aerate a little bit (pH goes up slightly). The biggest problem for people if they get lots of rain and don't have enough chlorine. Rain does carry a goodly amount of organic contaminants and so FC can go down pretty quick. Left unchecked, you can get algae in short order. But if you maintain your pool well and keep the FC at target, you'll be alright.

If I see rain coming on the radar, I will often bump the FC a tad before it makes it to me. But then, I'm a geek like that. :mrgreen:
Good. I'll blame my last 'issue' on the rain. Isn't there an old millie vanilli song.....nevermind. Putting the FC bump prior to coming monsoons in the 'ole beartrap...
 

anonapersona

TFP Expert
LifeTime Supporter
Nov 5, 2008
2,598
newguyjosh said:
What effect does rainwater have on my pool? It is still a little low, should I allow it to fill up with rain (gotta be better then my well water right?) or is rain water bad for the pool? I guess I dont know if I should keep the cover on or off during rainy days
1 - rainwater is free
2 - rainwater has no CYA, no FC, no CH and no TA (probably unless you are in a dusty area?)
3 - rainwater effect on pH can be higher or lower
4 - rainwater may also come with leaves and branches or mud from landscaping increasing chance for algae growth
5 - when the pool gets full and overflows all chemicals in the pool are reduced
6 - how the pool overflows may be a consideration

So, if your chemicals are perfect and you have trees and landscaping that create debris in the pool then I'd keep it covered. If your CYA or CH or TA are a bit high then I'd leave the cover off for some dilution. If where and how the pool overflows could create a problem with drainage, then beware of that. In any case you will have less FC by a little or a lot if there is debris added, so you need to bump chlorine up a bit afterward. If your water source is problematic, like metals in well water, then free clean water is wonderful and you can deal with the rest of it.
 

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