Solar cover question

[mh0520]

I got a solar cover for my above ground pool this season. Since getting it I have noticed that when I leave it on I see a lot of what I assume to be algae appear across the bottom and on the sides. It doesn't seem to appear in the vertical sides of the pool only on the the ripples in the liner where there is a horizontal surface. I'm not 100% certain it's not pollen but I'm treating it like it's algae. Last time it happened I did a slam and left the solar cover off and didn't have any issues for 2 or three days until I put the cover on. When I put the cover on it started to happen again.

I didn't modify the cover at all to trim the circumference or cut it in half. What are the recommendations for this?

My chlorine has been around 4 the whole time and my pH is a little low, around 7.2, but it seems like that's ok even if not ideal. As I understand a little low is better than a little high as far as chlorine effectiveness goes.

I'm thinking that if it is algae that I need to trim the edge of the cover to try to improve circulation. I suspect that the problem is either circulate or that it is actually pollen that is on the in the cover getting into the pool water.

Sorry, I know this has been discussed ad nauseum but I wasn't seeing recommendations for how to modify the cover for the pool.

 

[Msch99]

PH doesn’t affect chlorine effectiveness much at all. Recommend to lower it for a slam because you can’t check PH above 10FC.
We cut our solar cover to fit our agp.

 

[Griswald]

Algae is caused by a low chlorine level, how could a cover change that? Unless your level is too low for your CYA level????
With a solar cover on my SWG poo, I have to turn the SWG down...way down, or I will get high FC readings?

 

[mh0520]

I wouldn't expect it to cause it but it does raise the temperature making it easier for the algae to grow and also my concern is that it could be reducing circulation and causing dead spots in the pool where chlorine might get low.

 

[mh0520]

PH doesn’t affect chlorine effectiveness much at all. Recommend to lower it for a slam because you can’t check PH above 10FC.
We cut our solar cover to fit our agp.

How much did you cut off around the edge? It seems like the recommendation is about 6 inches of open water between the pool wall and the solar cover edge. Is that right?

Do you cut it in half as well?

 

[Griswald]

Right up to the walls. No gap.

 

[Msch99]

We weren't particular when we cut it. Some places it is short of the wall and in others it touches or runs up the side. We didn't cut in half.

 

[mh0520]

Right up to the walls. No gap.

We weren't particular when we cut it. Some places it is short of the wall and in others it touches or runs up the side. We didn't cut in half.

Got it, thanks guys. Sounds like leaving space around the edge isn't really necessary. I do need to check my CYA level. Out of curiosity, if it is a circulation issue where I'm seeing deadspots in the pool because the chlorine is low locally, could low CYA exacerbate this? I haven't checked that since gotting a better test kit last week so I need to make sure I'm at a good level there.

 

[Msch99]

My FC seemed to vary a bit depending on where I took my sample. I now sample where the lowest test seemed to be, figuring the rest was somewhat better. With liquid chlorine I think would have been fine, thinking circulation not optimal from swg generation and mixing.

I would think CYA though wouldn’t have low spots because not constantly generating or adding like chlorine.

 

[mh0520]

I would think CYA though wouldn’t have low spots because not constantly generating or adding like chlorine.

I was thinking that maybe if the CYA overall is low then maybe that allows chlorine to drop low locally more easily wheras if CYA is at a good level then the chlorine would hold better over the whole volume of the of the pool. This is just a guess, though; hopefully someone with more experience than I can say whether or not that is the case.

 

[mh0520]

Okay, so, I just measured my CYA and it measures around 60 which is a bit higher than I expected. I guess that's what you get when you trust the strips. This would require a minimum FC or 5 according to the chart on this site. So, that means that my FC levels in the 3-4 range are low.

My preference would be to lower my CYA level to around 30-40. Is there an easy way to do this? I would prefer to keep my chlorine low to limit reactions to the chlorine level. I have a chlorinator so I have increased the setting on that for the time being to bring up the FC level.

 

[mh0520]

My preference would be to lower my CYA level to around 30-40. Is there an easy way to do this?

Okay, so I just looked into this and it was what I thought it might be which is draining/diluting. The water level is a little low right now so I was filling it anyways. I'm thinking I'll just leave the solar cover off for now, let some water evaporate and just keep topping it off. Although, will the CYA reduce at all when water evaporates or will I need to actively drain some water? If so, any guess how much I will need to replace to drop it by the 20 or so ppm that I'm looking for?

 

[proavia]

By chlorinator, do you mean a device you put tablets in? If so, your CYA is going to continually increase as those 3" tablets contain CYA.

CYA level will not decrease with water evaporation. You will need to drain some water and refill to lower your CYA. Your other (actually best) option is to quit using thise tablets and begin using liquid chlorine. If your CYA is 60, and you start using liquid chlorine, you can easily manage your chlorine levels based on the FC/CYA Levels.

How are you testing your water? What test kit do you have? Fill out your signature with your pool and equipment info - include what test kit you have.

 

[mh0520]

I added the info that I know off the top of my head for my pool and equipment. I'll add more when I have a chance to go verify some of it.

I'm using a prevail chlorinator which uses trichlor so I think that is probably part of how the stabilizer got so high. my plan is to drain the pool a little at a time and then replace with new water and check the CYA levels along the way.

When you talk about liquid chlorine do most people just use bleach for this?

 

[proavia]

Yes, bleach - no "splashless" or additives. You can also find liquid chlorine at Walmart, Lowes, HD and the like. The liquid chlorine is usually 10%-12.5% --about twice as strong as regular household bleach.

 

[proavia]

Yes, bleach - no "splashless" or additives. You can also find liquid chlorine at Walmart, Lowes, HD, BJ's, OceanState Job Lot and the like. The liquid chlorine is usually 10%-12.5% --about twice as strong as regular household bleach.

 

[Dirk]

I would prefer to keep my chlorine low to limit reactions to the chlorine level.

What reactions? Like to your skin? It doesn't work that way. The CYA acts as a buffer. If you maintain the correct FC to CYA ratio, then you won't feel any difference if the FC is 2 or 5 or 10.

 

[mh0520]

Okay, thanks. So, I'm thinking that I should stick with mainly liquid chlorine or bleach for ever day use and then only use the prevail chlorinator if we're going away for a few days or something and won't be able to keep as as close an eye on the pool.

How much bleach does one typically add daily if you want to keep it around 3 ppm. I know it's going to be very dependent on the circumstances but I'm just looking for a rough idea. Are we looking at about 1/2 a gallon a day? for bleach and 1/4 a day for liquid chlorine?

 

[mh0520]

What reactions? Like to your skin? It doesn't work that way. The CYA acts as a buffer. If you maintain the correct FC to CYA ratio, then you won't feel any difference if the FC is 2 or 5 or 10.

We have allergies in the family so I try to keep the levels on the lower side.

 

[Dirk]

my plan is to drain the pool a little at a time and then replace with new water and check the CYA levels along the way.

That will certainly work. But that will take quite a while and end up using/wasting the most amount of water. Doing it all at once, unless you're worried the pool might collapse without all the water in it, is the most cost-effective way to go.