Re-starting rooftop solar and avoiding algae

[Surf Hawk]

Hi, we are in southern california, we don't close our pool for the winter, but effectively stop using it from November until March as the solar can't keep the temp above 80 degrees.

Every year in the spring I turn the valve to start up our roof-top solar, patch any leaks and start to get it warm. A few days later my filter pressure baloons and I start battling an algae breakout that takes a SLAM along with vacumming and filter cleaning to overcome. I'm guessing from all the gross stuff that was in the solar panels for 4+ months.

Is there a better way to re-start my solar every year? Should I be preemtively doing a SLAM on my pool when I first turn on solar after it being off for awhile? Thanks for any tips!

 

[cowboycasey]

That is exactly what I would do.. Bring it up to SLAM level before you turn it on and keep it there after turning on your solar... test using the OCLT and when you pass let it drift down

 

[Rocket J Squirrel]

@Surf Hawk, do you drain your panels for the off season? If not, that could be your problem.

 

[Surf Hawk]

Great responses, thanks.

@Rocket J Squirrel when I shut down of the season I do open the valve and let it drain into the pool, although I'm not that patient and probably close the valve before I should. At that the end of this season I will perform a more thourough drain.

@cowboycasey thanks for the affirmation. I did this method, brought it up to SLAM level and premptively been brushing and vacuuming, so far no algae (it's early though). I had forgot about the OCTL test, will run tonight.

Thanks for the help!

 

[Rocket J Squirrel]

@Rocket J Squirrel when I shut down of the season I do open the valve and let it drain into the pool, although I'm not that patient and probably close the valve before I should. At that the end of this season I will perform a more thorough drain.

My solar installer told me to leave the valves open all winter. And don't you have two, one high to let air in and one low to let water out? Leave 'em open to allow for pressure equalization across weather changes as well as to let the tubes dry out to avoid stagnant water in there.

Do you think there's any advantage to closing the valves after draining?

 

[Surf Hawk]

Actually I only have one valve, maybe thats my problem. I have a diverter valve near the filter that either goes to the roof or not. The return line has a check valve so water doesn't go up the return. There is a relief valve at the top that lets air in when the system is off.

To drain, I put the diverter valve half way and listen to the water drain back down, when I stop hearing the water I shut it to solar off.

Probably a janky system I need to fix someday.

 

[Rocket J Squirrel]

I kind of misspoke when I mentioned "valves." I have the same plumbing valves you do, plus 2 hose bibbs up at the panels. The hose bibbs are what I leave open for winter, not any plumbing valves.

 

[Surf Hawk]

I kind of misspoke when I mentioned "valves." I have the same plumbing valves you do, plus 2 hose bibbs up at the panels. The hose bibbs are what I leave open for winter, not any plumbing valves.

Ah, thanks, no I don't have any hose bibs. Are those installed on the panels themselves or on the PVC pipe leading to and from them?

 

[Rocket J Squirrel]

The higher hose bibb is installed in place of a panel's end cap. The lower one is dropping down from a tee in the plumbing. They sort of look like this:

Fernco HBC-4 REUSABLE CAP WITH HOSE BIBB, 4 IN

Buy Fernco HBC-4 REUSABLE CAP WITH HOSE BIBB, 4 IN online at DKHardware.com. Our Plumbing category offers a great selection of Flexible Fittings products at the best price!

www.dkhardware.com

 

[Rocket J Squirrel]

I should further mention that my panels lie flat on a pergola, not the usual setup. That's why the lower bibb has to dangle from a tee, to make it the lowest point. With a typical roof mount on a slant, replacing the highest & lowest end caps with these should allow complete draining. I'm always surprised how much water drains out of the panels.

 

[Surf Hawk]

I should further mention that my panels lie flat on a pergola, not the usual setup. That's why the lower bibb has to dangle from a tee, to make it the lowest point. With a typical roof mount on a slant, replacing the highest & lowest end caps with these should allow complete draining. I'm always surprised how much water drains out of the panels.

Forgot to say thanks for this tip, for some reason never saw your link to the tee. Just ordered a pair since I am battling crazy high chlorine consumtion after restarting my solar again this year. Want to drain better this coming off-season so will get these on.