Hi all,

How carefully do you all check and balance your water during a long period of heavy rain?

It's been raining in my area for a good week or more and during that time I've seen my chemicals literally go down the drain.

My salt levels seem to be just hanging in there and all other stats are generally OK at this stage. Chlorine is the main thing I'm watching so I stay on top of algae. The thing I'm seeing swing the most is pH which as has been discussed in another thread is most likely due to the heavy rain aerating the water.

So what to do... keep adding acid every couple of days, or do most people just wait until the rain stops before re-balancing the water?

Thanks,
Steve

You can get a sample from deeper in the pool and bring it indoors. A well lit room will have to suffice for testing but should be adequate so you can figure out what your pool needs.

You might think about boosting the FC level with some bleach but I would expect the salt cell's pH rise and the rain to mostly cancel each other.

Scott

In my experience, heavy rain can really affect alkalinity levels. Check this before treating PH, or PH may need adjusting a second time if you adjust alkalinity.

I stick to my regular schedule whether it's raining or not. In fact when it rains a lot, I test more often because it will affect the FC most.

Here, where we get 5 to 6 feet of rain a year I haven't seen it affect the TA much, if at all. My TA stays between 70 and 80 ppm all year. It all depends on where you're located and what the rain brings with it I suppose. If you use the chemicals and methods in Pool School you should be able to regulate your pool pretty evenly, even when it rains.

Thanks for the replies. Consensus so far seems to be to continue as usual during extended periods of rain. The only thing I'm needing at the moment is acid, so I suppose I'll just keep on adding it as usual. TA is coming down a bit but it could do with that anyway. My SWCG is keeping the chlorine levels up nicely. It helps having no sun and no swimmers. The rain seems to be easing finally so I'll check everything else in the next day or so and add what's needed then.

Just remember to take your water sample from fairly deep in the pool to get a more accurate sample. Near the surface will be lower levels of everything due to the dilution by rain.

Scott

Agreed. To do this, get a piece of PVC pipe. Plug the end with your thumb, plunge it in the pool, release your thumb, water will rise in the pipe. Clamp your thumb over the end, and quickly swing the pipe over a cup and release the water.

I do this all the time - you can test water when it's really cold and you're wearing long sleeves! Get your sample and carry it somewhere where you can sit and test comfortably. And dry, in your case.

Wow, what a great idea! I'm going to have to try this. How big a piece of PVC do you use?

Yeah fantastic idea Richard.

A small pitcher, upside down, arm deep, then turned right side up is fine for the sample to come inside and test.

Scott

I bought a 4' piece of 1/2" PVC at Lowes. It was cheap, don't remember exactly how much.

Your rain OUGHT to have near 0 TA, 0 CH, 0 FC, and 0 CYA (although I guess dust could affect the TA and CH values). So bear that in mind as you monitor pool water values. If TA and CH and CYA were on the low side, pay attention. Each of those is corrected by adding the individual chemicals as needed, per the Pool Calculator.

My pool tends to run high TA due to the tap water TA levels, so rain lowers the TA and the pH tends to stabilize up to a point. Lower than about 70 TA and the pH gets unstable in my pool (suddenly running too high or too low, it seems). Tap water corrects this in my pool but baking soda is faster.

As the CH lowers, I get to use cal-hypo for chlorine which is a bit cheaper than bleach when bought in the huge buckets. With SWG you would probably just add calcium, unless you had reason to shock the pool.

As CYA lowers, I get to use trichlor tablets in the feeder which frees me from bleach and acid as long as my TA is not too low. With SWG you would just add CYA.