Algae growing on sides of pool...

[paulmaz]

Good afternoon,

I have been following TFP methods for a few months now. I check my water nightly (wife thinks I am nuts...) and add chlorine daily. My CYA is around 25, and since I am scared of an algae breakout, I maintain my FC level between 5-9. I have never let it drop below 4. My CCs are 0. pH is 7.5. It increases almost weekly and I add MA. I scrub the pool weekly. Filter runs from 9am-9pm and from 2-3am. Polaris runs 2 hours twice a day. Water temp is around 84.
My issue is, this week, I ended up with green algae growing on the sides. Very fine, but noticeable and water was a tad cloudy. I ended up scrubbing the whole pool and raised the FC a bit more. This is the second time this is happened to me. Last time it after scrub and a vacuum, all was good.

My question is, what am I doing wrong? Bad circulation? I believe I have good flow, and filter runs 13 hours a day! (way too much, I know, but I was thinking I have a circulation problem). My daily FC loss is minimal with the sun and number of kids swimming in it (2-3) I pass an OCLT test. Do I need to scrub more often? I really do not want to maintain a higher FC, as I already think it is high. I tossed in the floater yesterday with two pucks, as my CYA is 25, and it could be a tad higher as temps are hitting 100+ here.

Any feedback is appreciated. I feel like I am doing everything by the books, and it gets depressing when I got home from work and pool had green on sides!

thanks,

 

[Mr Bruce]

We're hearing of a lot of TX posters having issues lately. It's been very hot and sunny there, like you said. You should up your CYA a little more aggressively to 40-50 range. Algae means not enough chlorine, either by testing error, circulation, strength of bleach, etc.

I am surprised though. If you really are keeping FC in that range, running the pump and the robot as often as you say, have not failed an OCLT that's a bit strange.

What's your pH range, when do you add MA and what do you target?

 

[paulmaz]

For pH, I add MA when it is 7.8 or above (two days ago it was 8.0) and I shoot for 7.2. I added about 40 ounces the other day, and when I tested next day, it was around 7.3-7.4.

I am testing daily. Water to 10ML, heaping scoop of powder, one second drops, etc. Divide by 2. Bleach is the Chlorinating liquid from Walmart (10%) good recent date.

I am wondering if it is circulation, as my pool is irregular shape, and I never get a perfect flow. When I test FC, I always check different spots.

 

[PAGirl]

Does the Polaris climb the walls? (I don't have one)

 

[paulmaz]

Does the Polaris climb the walls? (I don't have one)

Yes.

 

[Texas Splash]

Your scenario is odd to me as well for a couple reasons. If your FC is as high as you say, and it remains there ALL day/night, it would be very difficult for algae to live in that water because you're almost at SLAM level if your CYA is that low. The chlorine is very potent. Speaking of CYA, there's no way my pool could sustain a CYA of 25-30 in our SA area. Even at 50 my FC loss is quite noticeable. My CYA is at 60-70. So unless you get a lot of shade on your pool, that seems like a very low CYA which would leave FC as a very easy target to the sun's UV. FC could potentially drop very fast. But again, that brings us back to your statement about FC remaining constant all day AND you pass OLCTs? Just odd.

Perhaps on your next post go ahead and include a full set of results? That might help us figure this one out.

 

[pookiesunshine]

...
I am wondering if it is circulation, as my pool is irregular shape, and I never get a perfect flow. When I test FC, I always check different spots.

If not already doing it, take a sample in the area(s) you are seeing algae and compare to sample at area where no algae. But i would tend to agree that it might be lack of circulation. Try the ping pong ball test posted elsewhere at this site. But I think i would also increase the time the pump is on, at least until you get this figured out.

 

[paulmaz]

Pat, I do have a lot of shade. Tons of Live Oaks. Hence the water temp of 84. Others in my neighborhood are over 90. I will run a full battery of tests this afternoon and post. Will also work on raising CYA.

And yes, I have been very attentive to the FC for this reason, and that is why I am confused as well. Not confused, but mad, because I am taking a lot of pride in my pool and my wife thinks I am crazy pool guy.

 

[Texas Splash]

my wife thinks I am crazy pool guy

Welcome to the club! Once we see your results, we'll take into account those massive oaks, water circulation, and see what we can come-up with to help.

 

[paulmaz]

Here are my results. Yesterday evening my FC was at 6.5, and I wanted to get to Shock Level to ensure no more green stuff! So I added a jug of Great Value 8.25%. (121 oz) and added 2 pucks to the floater. (for CYA)

Readings at 4:14pm central
FC 11.5
CC 0
PH 7.6-7.7
CYA 25
CH 450
TA 100

cant believe my PH is that high already. I just added MA two days ago. Nothing jumps out to me. Hoping you pros know something I do not. Going to vacuum pool now, just to confirm my pool crazy guy status.

 

[Texas Splash]

Well, for the pH increase we can definitely help. You have a lot of wiggle-room to lower that TA with the acid/aeration method as seen on the Pool School - Lower Total Alkalinity page. I would definitely lower the TA to at least 70-80. If that doesn't work well enough for you, lower it down to 60. Let us know how that works.

On to the other mystery ... the walls. Puzzling. Regardless of the suggestions forthcoming, I would still increase the CYA to at least 30. The two tabs you added might get you there, so check again after they're gone. If you're receiving that much shade form the oaks, I can't help but wonder if a combination of constant shade and perhaps droppings is somehow contributing. A lot of our local oaks do have that fungus stuff that grows on them. Still ... your FC is elevated. I like the previous suggestion of testing yoru circulation. Ping pong balls, packing foam peanuts, anything small like that where you can watch the movement of the water might give you some clue. We all have one or two dead-spots, but for you it sounds more substantial.

Also, that stuff you're seeing ... are you able to grab any of it? Able to get enough to smear on white paper to see what it looks like?

 

[paulmaz]

OK, so on Friday I vacuumed up the pool, and all was clean. And all weekend the pool was clear. FC NEVER dropped below 7. Measured different areas. CYA today is still 25, so added another puck today. And guess what I had in my pool today when I got home from work? Some green dust on the stairs, ledge, and bottom of pool. I scrubbed entire pool down.

There is something else going on. I have left filter running almost 20 hours a day now. I know I read on here that algae cannot live with right FC levels. I know I have right FC levels. I have normal FC loss daily, and pass an OCLT. What could be causing this green stuff to form? This is VERY maddening!

Edit: it has been vey windy in San Antonio the last few weeks. I have MANY live oaks in my yard, and tons of leaves get in my pool. Any chance this coul dbe from the trees?

 

[Texas Splash]

Paul, I can sympathize with you. Very odd. I didn't go back to read your other threads (just this one), but even though you passed an OCLT, I think we need to re-address these items for anyone reading this thread:
- Have you inspected behind your light(s) in the niche if you have one?
- When was the last time you deep cleaned your sand?
- Do you have any hollow steps/ladder that protrude into the water? Anything that may be harboring algae?

Now since you have been so diligent on FC maintenance and performing OCLTs, any chance the stuff you are seeing could be related to the trees specifically and not algae? I'm no tree expert, but the wind these past few days (especially today) has been crazy. I have to think those oaks are losing some junk in your water. Not algae, but perhaps something that is contributing to that residue perhaps? Just trying to brainstorm here.

 

[paulmaz]

Pat, good morning, thanks for your response. To answer your questions:
- I do have a light. Visual inspection I do not see any algae around it. How do I go about cleaning in the niche? I am not sure how to do that.
- I have not deep cleaned the sand. To do that requires PVC cuts, and I am not sure I am ready for that. Is there any kind of test I can run to see if the sand is pretty dirty?
- I do not have any hollow steps for anything.

Looking at the stuff yesterday, it is green. It all came off with a brushing, and water is still clear. It does not seem like dirt, but algae or something like it.

 

[pookiesunshine]

....
- I do have a light. Visual inspection I do not see any algae around it. How do I go about cleaning in the niche? I am not sure how to do that.
- I have not deep cleaned the sand. To do that requires PVC cuts, and I am not sure I am ready for that. Is there any kind of test I can run to see if the sand is pretty dirty?
...

There should be a screw at the top of the ring around the light fixture. Unscrewing this will allow you to tilt the light back and lift it off it's hook at the bottom. Be careful not to lose the screw. I had a ton of junk in the niche behind my light. If there is not a screw at the top of your fixture, then you have something i am not familiar with and you should wait for someone else's advice.

How long have you had your pool? i did not see that in your sig or posts. If new, your sand is probably ok. But you should be able to remove the valve at the top of the filter to inspect it. If there are no unions in line or flexible hose that will allow you to do this, then your pool builder messed up. You will need to take the valve off at some point, so you might as well plan on cutting the pipes and adding fittings if you cannot take the valve off now. Again, if it is new, likely not an immediate need.

 

[paulmaz]

Thanks,
For the light, I can do this underwater? I do not need to bring the water level down do I?

As far as the filter, let me get a picture of the top, so you guys can advise me on how to make sure it is plumbed right. The pool is new to me as of this April, but I believe the filter was setup in 2012.

 

[pookiesunshine]

Thanks,
For the light, I can do this underwater? I do not need to bring the water level down do I?...

you can take out the light from it's niche while it is underwater. be sure the switch is off, might also want to turn off the breaker while you are working on it to be someone doesnt turn it on. There should be plenty of extra cord in the niche to allow you to place the fixture on the pool deck, or maybe even enough to let it set on the bottom of the pool. Be careful not to let it drop and jerk the cord, although the fittings around the cord connections should be tight enough that even if you do, it should be ok. just better not to test that.

 

[Mr Bruce]

Yes, underwater. Either sit on a pool noodle or reach down from the deck. Make sure the breaker is off! There should be enough power cable to rest the whole light fixture on the deck.