Recovering from a heavy rain

[CurtisT]

So we got about 5 inches of rain last week and it overflowed the pool and turned the water bright green (it does that every time we get heavy rains.. not sure why, I don't think it's algae because my chlorine usage doesn't increase... I guess it's gunk getting washed off of the leaves from the large Oak hanging over the pool or stuff washed in from the yard). 72 hours of running the pump has the water cleared up (just slightly cloudy actually). I thought I was done cleaning the filter for the winter, but I have to do it again now!

At any rate, I tested my water and need to adjust multiple parameters. I know generally what I need, but not sure in which order.

CL = 5
FC = 4.5
pH - 7.8 (needs to come down)
TA= 60 (needs to come up)
Ch = 160 (needs to come up)
CYA = 60 (needs to come up about 10 although not critical in the winter)
Borate = 30 (needs to come up to 50-60 although not critical in the winter)
Water Temp = 72.

So I know I need acid to lower pH, Baking soda to raise TA (but that will raise pH back up), Calcium Chloride for the Ch and eventually borax (which will raise my pH back up). My question is, what do I do first? I'm inclined to add the baking soda first, but then my pH will be way up and I'll have to add more acid which will bring my TA back down? I think I can raise my Ch any time. I'll probably dig into my stash of Dichlor and use about 3lbs of that over the next week to bring my CYA up and then wait until spring to tackle the borates.

 

[polyvue]

At any rate, I tested my water and need to adjust multiple parameters. I know generally what I need, but not sure in which order.

CL = 5
FC = 4.5
pH - 7.8 (needs to come down)
TA= 60 (needs to come up)
Ch = 160 (needs to come up)
CYA = 60 (needs to come up about 10 although not critical in the winter)
Borate = 30 (needs to come up to 50-60 although not critical in the winter)
Water Temp = 72.

Do you have a SWG? I ask because otherwise the CYA is a bit high. I run my SWG pool at the lower end of the recommended 50-80 ppm of CYA.

So I know I need acid to lower pH, Baking soda to raise TA (but that will raise pH back up), Calcium Chloride for the Ch and eventually borax (which will raise my pH back up). My question is, what do I do first? I'm inclined to add the baking soda first,

Your inclination is good.

but then my pH will be way up and I'll have to add more acid which will bring my TA back down?

That's OK. The main effect will be an increase in TA; the pH increase will be slight.
The rest of your plan sounds fine, too. Here are Recommended Levels.

I think I can raise my Ch any time. I'll probably dig into my stash of Dichlor and use about 3lbs of that over the next week to bring my CYA up and then wait until spring to tackle the borates.

 

[duraleigh]

and turned the water bright green (it does that every time we get heavy rains.. not sure why, I don't think it's algae because my chlorine usage doesn't increase...

If your pool is green, that's about a 95% chance you have algae. How do you get rid of the green?

(but that will raise pH back up),

Not enough to matter much.

 

[CurtisT]

Polyvue,

No SWG.. just chlorine.. I'm usually shooting for about 75 in the summer here in Houston, but probably don't need it quite that high in the winter.

Dave,

I did add enough bleach to raise my FC to about 10 just as a precaution but just running the filter for about 3 days cleared it up. I've had this happened three times in the year and a half since I've had the pool (once after a hurricane) and each time the filter clears it up in 3-5 days. I really don't believe it was algae (at least all of it) just because I don't think I added enough bleach to clear up algae that looked that bad, but I guess it's possible. My FC went from about 10 to 4.5 in three days, which is not a whole lot more than what I've been losing lately. I'll probalby do an overnight FC test once I get things stabilized.

Thanks for the advice.

 

[polyvue]

No SWG... recommended minimum chlorine level is 5.5 ppm Free Chlorine (FC) for your pool that has 75 ppm CYA. If FC drops under 5.5 ppm you heighten the risk of algae formation. I think Dave's on to something and you have probably had low levels of algae in your pool for quite a while. You are able to beat them back with slightly higher doses of chlorine (10 ppm) but they're still around. The winter cold and sustained chlorine will ameliorate furthur algae growth, but this may come back in the spring. In any event, it seems you have a good feel for managing your pool.

 

[duraleigh]

About the only two instances I can think of for a pool to turn green is a sudden dose of chlorine with high iron content in the pool water (that certainly doesn't describe what you're reporting) or an algae bloom due to inadequate chlorine.

Unless I am forgetting something, I don't think there's any other causes.

 

[polyvue]

About the only two instances I can think of for a pool to turn green [are ...]

Unless I am forgetting something, I don't think there's any other causes.

Green plaster?

Hey Curtis, I came upon a thread where you spoke of an Access database that you created to track your pool maintenance. I'd be interested in seeing that if it's still available. The download link you provided in the post led to an error: HyperFileShare Error I currently use an Excel spreadsheet template that I print to hardcopy for logging of test results, but it would be cool to be able to convert my paper logs to electronic format. Thanks... Greg

access-database-for-tracking-pool-data-t15003.html

 

[CurtisT]

About the only two instances I can think of for a pool to turn green is a sudden dose of chlorine with high iron content in the pool water (that certainly doesn't describe what you're reporting) or an algae bloom due to inadequate chlorine.

Unless I am forgetting something, I don't think there's any other causes.

Perhaps next time I know we have one of these big 3+" rains coming, I'll raise my FC to shock level (so that when the pool overflows and I lose some water, the FC stays above the recommended levels) to see if that prevents the issue. It might at least save me the filter cleaning that comes when I clean it up after the fact.

"turn green is a sudden dose of chlorine with high iron"

This peaked my curiosity... is iron likely why the pool was an emerald green when it is freshly filled? I always assumed it was minerals in the water of some sort, but wasn't sure exactly which one.

 

[Tonedeaf]

I have been in the same boat many times over the past year with heavy rains. My worst was back in May when it was a dark green and took over a month to finally clear up completely. LINK

Pump on 24/7 is the best way to clear it, and keeping on top of the chlorine.

Finally had the builder out to put in some drainage on one side of the pool which has helped tremendously.

 

[CurtisT]

Yeah.. your picture and experiences very similar to what I had although mine wasn't near as bad. Last year after the hurricane, it took about a week to clear up, but I was having to clean the filter 4 times / day for the first two days and then ramped down during the week.. all in all, about 15 filter cleans during the week (wound up aggregating a pre-existing back conditioning and having to have surgery out of the deal!). Three other times now since then, we've had significant rains that caused a lesser problem... in general (and this most recent time falls into this category), the pool clears up with about 3 days of running the pump and one extra filter cleaning. Odd thing is this happens to me and my neighbor, but he guy down the street does not have the issue at all. I need to work out a way to direct water out of the yard and to the street without it running into the pool. The problem is, that when the streets fill up, the drains don't work well. I'm thinking I'll have to get a pump to run during these rains to pump it out there quickly.