Re-occurring algae spots, maybe?????

[gt6974a]

This year we put in a SWG (professionally installed) and 2 weeks ago we had what we thought were algae spots, mustard, and cloudiness.

I SLAMMED the pool and everything cleaned up and went away. Before and After slamming we have brushed, scrubbed, and chlorox'd the liner, steps, ladder, rails, diving board, slide, and pool tools. Even before slamming my CC was fine and the chlorine has been high ~8ppm as we learn how to use the SWG.

We were running the pump at 12 hours a day and 100% chlorinating but have since back off to 8 hours and 70% chlorinating and the chlorine is still staying high at around 7.5ppm with no CC.

I thought my salt was a little high using the test strips to test with but I went ahead and had the local pool store test it today. Their numbers are pretty close to mine except for Salt and I don't bother with the phosphates.

I use the TFTest recommended test kit and we use a Dolphin to clean the pool. Still brush.

Here's the test results today from the store, 33K pool:

FC 7.5 (I'm at 8)
TC 7.5 (I'm at 8)
Salt 2000 (I'm somewhere around 3200 with test strips which I don't like)
CH 140 (vinyl liner pool) (I'm a little higher)
CYA 80 (this is what I get)
TA 100 (I get 110)
pH 7.6 (I'm very close to this)
Copper 0 (don't test for myself)
Iron 0 (don't test for myself)
Phosphates 2000 (don't test for myself)

Anyway, I don't see how the salt can be low if I'm producing that much Chlorine, constantly. How accurate are these guys for testing Salt (National chain guys)??

CH low, but it's a vinyl pool

Phosphates, I've never fooled with

Basically the pool get's a cloudy and you could barely see a couple algae spots, though much easier with polarized sunglasses.

Any suggestions on what we need to address?

Thanks,
Ryan

 

[lightmaster]

Does your SWG give a salt ppm readout? If so, what is it? And with a SWG, I'd recommend getting the K-1766 Taylor Salt Test so you have a much more accurate test result. When I had a pool store test my water earlier this year (or of curiosity) they were 1500 below what my test and the SWG said it was at.

When you did the slam, did you check everywhere that the algae could have hidden?

 

[duraleigh]

Basically the pool get's a cloudy and you could barely see a couple algae spots, though much easier with polarized sunglasses.

What do these spots do when you brush them? When do they appear? Do they reappear in the same spot. We need more info JUST about the spots to make a determination.

 

[gt6974a]

Does your SWG give a salt ppm readout? If so, what is it? And with a SWG, I'd recommend getting the K-1766 Taylor Salt Test so you have a much more accurate test result. When I had a pool store test my water earlier this year (or of curiosity) they were 1500 below what my test and the SWG said it was at.

When you did the slam, did you check everywhere that the algae could have hidden?

No, it's Jandy Pro Series, does have a 'Low Salt' readout for < 2500 ppm. Test strips this morning are all over from 2500 - 3500. I bought your recommended test but I'm confident it has salt b/c it's making Chlorine. At 8 this morning.

Slammed 2 weeks ago, yeah we scrubbed everything with chlorox, including toys

- - - Updated - - -

What do these spots do when you brush them? When do they appear? Do they reappear in the same spot. We need more info JUST about the spots to make a determination.

The spots bloom up into a cloud. They are in the corners of the deep end and in the shallow end where the wall meets the bottom. Same as last time

Also note, this is mustard algae, we never get regular algae. It's always mustard that we get around here.

 

[gt6974a]

see attached pics

 

[duraleigh]

1. If you are making chlorine, your SWG is happy. For now, I'd leave your salt alone.

Any suggestions on what we need to address?

Yes. You need to SLAM the pool....again. You either never finished the SLAM completely or let FC drop too low at some point. Regardless, the only correct answer to a pool with algae is to SLAM

 

[lightmaster]

When you SLAM again, make sure to check the foam on the backside of your skimmer's weir, check behind any lights (some people have seen some horror scenes of algae hiding here), check the bag/basket of any pool vacuums, under the rungs of your ladder, and if possible, try to spray a mixture of bleach and water inside the hollow metal tubes on your ladder. Anywhere where there is low water flow, algae can hide out in and avoid the high FC levels of a SLAM, then start coming back when you lower the FC after a SLAM.

Have you read the Pool School page on Mustard Algae?

 

[gt6974a]

Have you read the Pool School page on Mustard Algae?

Hmm, I remember reading that but have never gone that high. Maybe that's my problem. I took her up to 32 ppm tonight so after SLAM is complete, I need to go up to 46. 2-3 weeks ago my CYA was lower, only 60 so I did bring her up to ~23ppm, SLAMMED, no CC, cleared up then let it float back down. I then brought the CYA up to 80 on b/c the pool now has a SWG. Chlorine as been 8 - 12ppm for last 3 weeks, no CC, and clear. So that's what was bugging me. Last year it wasn't on a SWG, so this is new to me, Mustard is not, but have never gone this high to eliminate. Guess, I need to try.

This morning I was at 8 ppm, this evening I was down to 6 ppm before slamming so it's obviously eating something, and that algae must be exploding is all I can tell.

Guess I'll wait until SLAM is complete and then head on up to 46ppm.

60 ............... 4.4 ............... 6.8 .................... 9.0 ................... 23.7 ................ 34.9²

80 ............... 5.8 ............... 9.1 .................. 12.0 ................... 31.4² ............... 46.1²

 

[lightmaster]

Hmm, I remember reading that but have never gone that high. Maybe that's my problem. I took her up to 32 ppm tonight so after SLAM is complete, I need to go up to 46. 2-3 weeks ago my CYA was lower, only 60 so I did bring her up to ~23ppm, SLAMMED, no CC, cleared up then let it float back down. I then brought the CYA up to 80 on b/c the pool now has a SWG. Chlorine as been 8 - 12ppm for last 3 weeks, no CC, and clear. So that's what was bugging me. Last year it wasn't on a SWG, so this is new to me, Mustard is not, but have never gone this high to eliminate. Guess, I need to try.

This morning I was at 8 ppm, this evening I was down to 6 ppm before slamming so it's obviously eating something, and that algae must be exploding is all I can tell.

Guess I'll wait until SLAM is complete and then head on up to 46ppm.

60 ............... 4.4 ............... 6.8 .................... 9.0 ................... 23.7 ................ 34.9²

80 ............... 5.8 ............... 9.1 .................. 12.0 ................... 31.4² ............... 46.1²

PoolMath gives slightly different targets than that chart, and I would trust PoolMath more than a post from a couple years ago. According to PoolMath, 80ppm CYA, shock is 31ppm FC, Mustard Algae is 44ppm.

Have you preformed a proper OCLT yet?

 

[gt6974a]

PoolMath gives slightly different targets than that chart, and I would trust PoolMath more than a post from a couple years ago. According to PoolMath, 80ppm CYA, shock is 31ppm FC, Mustard Algae is 44ppm.

Have you preformed a proper OCLT yet?

Before I did, but just SLAMMED tonight.

On the last tests, I thought I did, but now looking back and thinking about it. The SWG could have been running for an hour or 2 in the morning before I retested, thus creating enough chlorine to cover for the loss of FC.

I just know for 2 of the weeks the Chlorine stayed at 12 until I dropped the SWG down to 70% and then it held at 8.