Recurring Algae (in filter?)

[sdf8]

I've been lurking out here for years and following the general tenets of keeping my water clean. However, after a couple of weeks, it gets cloudy then green, despite the addition of more and more bleach. The chemistry is fine, at least until things get really funky.

Over time, I realized I needed to clean the filter more often to stay on top of this. But, I'm still puzzled what is going on. I don't have any drop in pressure. I don't have a lot of gunk (other than algae) in the filter. I usually go in later in the day and don't need sunscreen because of some shade from a hillside.

At first, I thought it might be all the trees (spruce and deciduous) in the vicinity. Just pollen build up or whatever. However, last year we took a few trees down and it is much more open around the pool. Admittedly, it seems to have helped, but the problem still occurs in something under a month.

It almost seems like the problem is emanating from the filter. It (and the water in the chamber) are considerably greener than the pool itself. In fact, I don't really let the pool get green at this point.

I haven't done anything extraordinary to clean the filters other than a good spraying. I assume a better cleaning would help, but I'd think the chlorine in the pool would kill any algae in the filter and that wouldn't be an issue.

The pool is a 21' above ground pool. No sand or salt or anything. Just plain-jane filtering. Chlorine comes from bleach. The CYA is usually about 30 but I adjust the chlorine level to match the current CYA per the tables on this site. The TA is around 90 and PH is 7.4. When it works, it works great. But, at some point, it just gives up...

Any thoughts would be appreciated.

thanks,
sf

 

[duraleigh]

Hard to say what the issue is (although I suspect high CYA) but always keep in mind that algae needs sunlight to grow so it is not growing in your filter.

 

[Texas Splash]

Hey SF! At this point, I am suspicious that a TFP SLAM Process may be in order simply because you appear to see algae. It would be helpful if you posted a full set of water test results just so we can see the latest numbers. Tell us if you are using a TF-100 or Taylor K-2006 test kit. Perhaps you might also consider performing an Overnight Chlorine Loss Test as well?

 

[Catanzaro]

Because you have an AGP and are following the TFP guidelines, IMO I believe you have limited circulation and/or the lack of brushing the pool walls. A SLAM is in order. In addition, you stated the current results, but have not mentioned how the water is being tested. If the results are derived by anything besides the recommended test kits, they are not valid, and this could be the issue.

Please provide us some additional details. Thanks!

 

[sdf8]

Thanks for the replies, so far. I am using the TF-100 test kit for testing.

Measuring CYA is a bit more subjective than some of the other tests, but I feel like I'm plus or minus 5 on it and adjust chlorine levels to allow for a margin of error.

I'm really describing a recurring phenomenon but the pool is not currently green. Certainly, a SLAM is done whenever it gets green. And, I haven't done the overnight test, recently. I tend to go down about 1 ppm in 24 hours, much less overnight. Everything is just fine...until it is not. Admittedly, I could perform the test once it starts going South, but by now, I pretty much know it is happening so I just move on to the SLAM.

I will try more diligent brushing and maybe longer circulation times. I'm admittedly not as good about brushing as I should be.

Any recommendations on pumps? I remember reading several years ago about lower powered (maybe 2 speed) pumps running longer cycles. My current pump is overpowered and I tend to run it in shorter cycles. It gets plenty of turns, but perhaps more constant running would help things.

thanks,
sf

 

[duraleigh]

I agree that a 2 hp pump (what's the "service factor" on the placard?) is too big. You don't say the size of your filter but it is probably too small for that pump. A 2 speed 1 or 1.5 HP pump could pay for itself in short order if you run it on low....perhaps 24/7

Brush your pool. There is no substitute for physically touching your pool surfaces to keep algae away.

 

[Catanzaro]

Thanks for the replies, so far. I am using the TF-100 test kit for testing.

Never any substitutes on this test kit. Great job!

Measuring CYA is a bit more subjective than some of the other tests, but I feel like I'm plus or minus 5 on it and adjust chlorine levels to allow for a margin of error.

Add 10 ppm on the CYA test to what you believe the number is and keep the FC at the recommended based on this figure.

I will try more diligent brushing and maybe longer circulation times. I'm admittedly not as good about brushing as I should be.

Above ground pools need more frequent brushing. There is no substitute.

Any recommendations on pumps? I remember reading several years ago about lower powered (maybe 2 speed) pumps running longer cycles. My current pump is overpowered and I tend to run it in shorter cycles. It gets plenty of turns, but perhaps more constant running would help things.

No need to swap out a pump unless you have to. If you brush your pool every other day, right before the pump turns on or at least within 30 minutes after, based on your pool and pump, 6 hours is plenty. Usually does not matter what time of the day you run the pump.

I am by no means a pump expert, but if your plumbing is small, your filter undersized with this type of pump, you could literally be wasting electricity and placing a lot of strain on the pump. I have 2" plumbing with a 350 lb. sand filter and a 2 hp. Hayward Super Pump (Single Speed). I changed my pump after 4.5 years and should have gone VS, but too late now. To compensate for this, I have my pump run time down to 6 hours, instead of 12 hours (like PB told me years ago) and each year I have been running the pump less and less. My pool is still crystal clear and only reason why I am at 6 hours if for the heat pump to maintain the temperature of the pool.

Work with the brushing and keeping the FC slightly higher and report back to us after a week or so. Thanks!

 

[sdf8]

Hi Folks,

Well, it has been a month and I've been brushing the sides of the pool with more regularity...not quite every other day, but at least two times a week. While I'm doing it more frequently, I can't say I'm doing it especially thoroughly. I'm mostly just vaguely "sweeping" the sides with what amounts to a broom, much like you would a garage floor. Even with that half hearted effort, the pool is crystal clear after a month. Clearly I wasn't doing it often enough before. And, clearly, you don't have to scrub with excessive care. Just getting a quick pass over it a couple times a week seems to make a considerable difference. Of course, if it starts getting cloudy, I'll have to be more thorough. But, at least now I know where the problem lies, if it creeps up on me again.

Thanks for all the help and suggestions.

sf

 

[Catanzaro]

While I'm doing it more frequently, I can't say I'm doing it especially thoroughly. I'm mostly just vaguely "sweeping" the sides with what amounts to a broom, much like you would a garage floor. Even with that half hearted effort, the pool is crystal clear after a month. Clearly I wasn't doing it often enough before. And, clearly, you don't have to scrub with excessive care. Just getting a quick pass over it a couple times a week seems to make a considerable difference. Of course, if it starts getting cloudy, I'll have to be more thorough. But, at least now I know where the problem lies, if it creeps up on me again. Thanks for all the help and suggestions.

The nylon brushes are designed for ease of use. It is suggested you brush twice weekly. You may be able to get away with once per week, but if you forget, the pool may run into another problem, which you now know that is more time wasted than spending 10 minutes every 3-4 days.