algae or pollen problem

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B

b00k3

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Aug 30, 2008
10
Hi all,

I've been following this forum off and on for years. It's worked really well for us, for the most part. We've opened our pool three seasons now (skipping last season), and we've only ever had one algae problem, and the guidance here got it cleaned right up.

That said, I have something on the bottom of my pool now. I'm not so sure it's algae. It's kind of brownish, and when it kicks up, it makes the water hazy. It appears to only be on the bottom. It settles mostly on the ends where circulation is less, but has left a pretty even coat of dust across the bottom of the pool, with none in a triangle in front of the return. (whatever it is, it appears to not stick very well under direct current. It just settles.) But my FC consumption is pretty normal. (1 a day or less). Last time I had algae, I seem to be shocked at reading a 0 FC once, so I was immediately suspicious then. This time, if the clarity and the dust on the bottom weren't present, I would suspect nothing was wrong at all.

It could be pollen, based on what I've read here. We do have pine trees around, but I hadn't noticed higher-than-usual activity from them. We usually keep a solar cover on the pool, but it has been open for a few afternoons lately, and stuff can blow in even with the cover on.

here's what I've got:

An Intex 20' x 12' x 48" oval frame pool (about 4500 Gallons). I think it came with a 1500gpm filter pump. I change the filter every few weeks; I changed it last week. I hose it off about once a week if I don't change it. We are in Oregon, not far from Portland.

CYA is about 40.
TA is about 90
pH was last seen at about 7.6. (it tends to drift down -- I just bumped it up with some borax last week when it read 7.2)

I've kept the FC above 3 most or all of the time. Yesterday it was about 4, and that was with nothing added the day before.

I have a TF100 test kit that I bought two seasons ago. I have kept it indoors, out of the sun. When I opened the pool this year, I tested the chemicals on some tapwater, and also on the poolwater as I got TA and CYA where I wanted them. I have opened this pool a couple times before, so I know, using the calculator, what to expect when I add the right amount of CYA, baking soda, bleach, borax, etc. I concluded that the FAS-DPD was not reliable at all. It measured the FC much higher than I knew it to be (2-3x). So, I don't use that test. Everything else in the TF100 seemed to register what I would expect when I opened the pool. The color-block FC test registered 0 on tap-water as expected. With the levels I have, the color block test can tell me pretty well if I'm above 3, so if I see it start to get below 5 (the max of the test) I just bump it back up to 6-7. It seems manageable as long as nothing goes wrong.

This may seem cheap, but it's gotten me a couple months into the season. I plan to get refills next season, at least for the FAS-DPD.

I have added only CYA, Bleach (liquid, 6%), Baking soda, and Borax. (Lately only bleach and borax)

Anyhow, I explain this because what it implies is that I'm not 100% certain of my numbers. But I'm hesitant to go buy test chemicals half way through the season, when I'm still pretty sure these are doing ok, and I haven't seen anything resembling a sharp FC drop regarding this brownish dust problem.

So, once I saw it all settled, I tried vacuuming it up. The included vacuum picked it right up. It was plain to see where I had vacuumed. The pump appeared to spew it right back into the pool, because it was a cloudy mess again by the time I was done. I pulled the filter and hosed it off half way through, and there was a lot of brown int he chamber and a fair amount on the filter, but it hosed off easy enough. But it appears the filter isn't catching everything.

I've heard bad things about Intex stock pump/filters on smaller models, and I read lots about how they're so pleased when they upgrade to a sand filter. So I started looking into that. But after looking closer, I see people mostly complaining about Intex pump/filters being under-powered, not about them being lousy at filtering out cloudy water. I was looking at the Intex 1600 GPH model (About $160), and about to spring on it, but then I read a post where it said that the cartridge filters actually filter better than sand. My problem seems to be I can run this pump all day (usually 8 hrs is enough) and it's not getting the job done... but I don't think it's that it's underpowered... It's just not picking the dust up. The 1600 GPH isn't that much stronger than my stock 1500 GPH... If it's not filtering better either, what's the point?

So... I'm wondering what people think. Would upgrading to a similar-powered sand filter help? Buy some test refills? Something else I should try?

Is it possible to have algae that doesn't quickly kill your FC level?

thanks
 
Since you lose 1 ppm FC per day or less, you would pass an OCLT if you did one. And the description definitely sounds like pollen more than algae. A skimmer sock might help.

In terms of filters, DE might do better than anything else - or at least sand+DE.
 
Add some DE to your filter by following the instructions at pool school. I had the exact same issue you describe and that cleared mine up in 2 days.

Be sure to check the pressure as often as possible though. Mine went way high after a few hours and needed a backwash.
 
Can you add DE to an intex cartridge filter? I didn't think you could.

I've put a sock on the return. It gathered some green. I even tried a sock within a sock... that seemed to collect some. I get the feeling it's not getting very much though. pretty cloudy still. I've seen lots of references to the sock, but haven't come across any official sock instructions. Are there any tricks to it?

thanks.
 
The sock on the return captured some green, but not all that much. It didn't solve the problem much.

I caved and got an Intex 1600GPH sand filter & pump and installed it last night. I snagged one on Craigslist that was apparently a resale from the Walmart pricing error a month ago or so. The water looked clearer this morning, but there's sediment on the bottom again. I'll try vacuuming tonight and see if it catches it. If not, I may try the DE.

I had some days where chlorine consumption was up, but they were also days I had the cover off all day. It still hasn't zeroed my FC yet, but I'm watching it pretty closely for that.
 
b00k3 said:
I caved and got an Intex 1600GPH sand filter & pump and installed it last night. I snagged one on Craigslist that was apparently a resale from the Walmart pricing error a month ago or so. The water looked clearer this morning, but there's sediment on the bottom again. I'll try vacuuming tonight and see if it catches it. If not, I may try the DE.
Click to expand...
Good choice on the sand filter, it is much better than the stock intex cartridge (they are worthless in my experience). Intex cartridges are not equivalent to the cartridges found in better filters and are worse than any sand filter I have used.

b00k3 said:
I had some days where chlorine consumption was up, but they were also days I had the cover off all day. It still hasn't zeroed my FC yet, but I'm watching it pretty closely for that.
Click to expand...
If you are still suspicious, raise your FC level up towards normal shock levels for your pool (don't have to go all the way, just higher than normal range) and do the OCLT and check CC in morning. I have seen instances where at normal FC levels there is not a 1 ppm drop, but at shock levels there was and the shocking process was required to remove the organics.
 
Did you also add a skimmer sock? I buy the ones at WallyWorld when they are in stock - otherwise, the pool store. They capture tons of gunk before it has a chance to go to the filter.

Let us know how it goes w/the new filter.

I like the idea of raising FC to shock level tonight and doing an OCLT.
 
Howdy Neighbor!

I'm a little stumped about your assessment of the FAS-DPD test. I'm certain it tests properly, when I dose it's right on the nose. The OTO test just pizzes me off, it's never right or I'm just incapable of judging yellow maybe, but it is not something I feel I can rely on. The FAS-DPD is however, very reliable and accurate.

Our water actually has just under 1ppm of chlorine in it and all the municipalities around here treat about the same. So, if you're judging the test results you're getting based on 0ppm chlorine from the tap it's in slight error. It's not legal to not chlorinate municipal water in some way. Bull Run water is disinfected by chloramination which is chlorine plus ammonia (simply put). .97ppm chlorine won't register on an OTO test, but it doesn't mean it's not there. Other areas here might use chlorine gas or salt water generation but it all has chlorine. When Portland draws from the emergency wells by the Columbia the chlorine is well above 1ppm, I can smell it. I tested the tap water here recently with a Hanna meter designed for drinking water testing. I also posted here about it. Fairly certain we weren't drawing from the wells at that time cuz it was June and you likely are keenly aware that there was no shortage of water back then hehe...

Anyway, I think I just wanted to point out that your FAS-DPD test is accurate. Very accurate in fact.

Additionally... the Intex filter media SUCKS! I would bet that after a week with the sand filter and perhaps some DE you'll see the fine silt gone. I've battled it all summer till I put the walmart brand cartridges into the pumps and voila! 3 hours later the difference was amazing. I haven't vacuumed in over a week now and I was doing it every day, the dust would settle right back on the bottom within hours.

If you want to see the silt go fast, get one of those walmart filters and stick it on your old pump. Hang the suction at the bottom of the pool over the side weighed down so it won't rise and stick the return also over the side pointing towards your skimmer. Give it a day, maybe two (two of those suckers does the job fast, but one might take longer) and see if it goes away. They plug up fast, prepare to change it once the flow is reduced (blow out w/water and replace) but I think it'll clear the water for you and then you can run the rest of the season w/the sand filter alone.
 
Thanks for all the replys, folks.

Maybe I wasn't clear about why I don't trust my FAS-DPD. The reagents were bought beginning of summer 2009. One of those reagents is in an opaque bottle, and is rumored to be very light sensitive. The powder is also rumored not to age well. When I opened the pool, I put a known amount of 6% bleach in, and tested the test by checking the FC level a short time later. It measured 2-3x higher than it should have (like upper teens when it should have been 6.) I don't trust those reagents. They were great, back in their day.

My OTO is also that old, so it may not be trustworthy either. I don't recall if tap water's < 1 registered on it when it was fresh or not. Based on knowing the pool and the bleach, it doesn't seem to be too far off.

Based on the one algae problem I had 2 summers ago, I'd be a bit surprised if this were algae. It's almost 48" deep, and when it's stirred up a bit I can't even see the pattern on the bottom. Whatever it is, it's that visible, and yet it still doesn't seem to kill the FC like the time I had algae. I've been keeping the FC well above 5 just to be safe. I bumped it up to (what I think was) 9 or 10 a couple days ago (close to shock), and it's still above 5 (the most the OTO will register). I will not rule out algae without having a FAS-DPD I trust, though. That may still be it.

Skimmer sock. I had to look that up. I haven't seen one. I don't follow how it would help, though. The skimmer gets what's on the surface... This stuff is already submerged. I keep the pool covered (unless I'm working on it ) now. Wouldn't that just better help catch stuff that has fallen on recently? and then only when I have the skimmer on? (this is an intex... skimmer is only present when I put it there -- when the cover's off and people are out)

Here's the update: The sand filter's been running for a day now, and the stuff settled in the usual pattern. I vacuumed it up, again. (faster now!). It appears to have spewed it back in again. Faster.

I think I'm going to try the DE next. The walmart filter may work, but I don't have that pump hooked up anymore, and walmart's further away than the pool store. I could get fresh FAS-DPD for about 20 which could help me rule out algae... I think I'll just try the DE first. Dead or alive, the filter is not catching this stuff.

Thanks again, all.
 
Definitely get new reagents if you're not confident in the ones you have. You really need a working FAS-DPD, especially when addressing a potential algae problem. Even if the DE clears the water, it will be wise to do a proper OCLT to see whether there's anything else needed. Plus you need it for regular maintenance.
 

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When you tried the FAS-DPD earlier this year, did you use the 25ml sample or the 10ml sample?

When you said it was 2-3x what it should be, that would be about right if you were using the 25ml sample and counting the drops as .5ppm instead of .2ppm.

Sounds like you know what you're doing with the testing, but this has been seen in the past recently when peeps get high chlorine readings with the FAS-DPD and the solution was to use the 10ml sample instead. Just wanted to put it out there as a possibility.

As far as new reagents, I'm not sure which pool store you're thinking of but if it's the one in Clackamas their DPD powder is over $15. I bought one this spring, and then proceeded to spill it all out onto my patio. I then decided to order from TFTestkits.net and got TWO 10ml containers of powder for less than the one at Norflow. Of course there's shipping involved but if you need any other reagents the shipping ends up being negligible in comparison. TFTestkits ships very fast as well. I couldn't have been happier. The gas to get to the pool store and back is about as much as shipping was anyway.
 
I'm pretty sure I was using FAS-DPD correctly. I've used it lots before, and I was reading the instructions as I did it to be safe. Unless you've seen 2-3 year old FAS-DPD reagents work perfectly, I think we should just take my word that these reagents are bad.

Yesterday, I caught a pool store open right as it was closing. Same one that sold me sand for the new filter. He admitted he doesn't carry DE. (sheesh.) So he sold me some flocculant for $9 and told me to vac to waste. At this point, I'm about willing to try that. I may try it even without the flocculant. This stuff settles within a half day by itself. It's only cloudy when it gets kicked up. Anybody see any problems with this plan?

Now I'm just trying to figure out the best way to vac to waste. The Intex hoses that ship only go so far. I could really use a 20 ft hose to get to the drain. But, the pool store doesn't carry Intex hoses either. (I don't know what they do carry at this point. Pretty useless store.) Looking online, I don't see anybody carrying longish Intex hoses anyway. I guess I need an adapter that would allow me to use a less proprietary hose. There are lots of adapters online, but it's a tough call which is what I need. If anybody's bought one they liked, that might be handy to know which one it was. I may be able to get away with moving the pump closer to the drain this time, but longer term, it'd be nice to just leave the pump where it is and use a longer hose to drain.
 
I think H bought a hose kit at walmart last year. It had like 4 hoses in it, a few adapters, hose clamps, some double circle hose holders, etc.

If you're in town sometime, I've got extra fresh DPD powder (a whole 10ml container) and could spare a few ml of R-0871 so you can run some CC tests. I'm near Eastport. Now you got me worried my extra container of powder won't be good next year. Doh!

Someone mentioned this solution a few weeks ago but I haven't tried it. They said to attach a garden hose to the regular vacuum that comes with the intex pool and create a siphon to vacuum to waste. I guess I gotta search "siphon" now to find the post :~}
 
an update...

I figured out that if I unplugged my return and moved the whole pump over, I could just make the waste hose reach the waste. So I let it settle and vac'd to waste a couple times. The flocculant said it could also be used as a filter aid, so I just used it that way. I don't know how much that helped.

The water's passable now. We went swimming Saturday. There's still a bit of sediment -- Might repeat the process another time or so, but this will definitely get us through the end of the season. (assuming this isn't some algae thing that just keeps generating sediment -- doesn't seem to be the case so far)

Thanks for the tips, all.
 
Another update.

Good grief. The vac to waste helped things a bit, but never got all of it. There would always be a bit of gunk settling within a day of being kicked up.

At some point it was clear enough to not mind swimming in, and a short time later it was too cold to swim anyway. It was ultimately solved by draining the pool at end of season. I'm quite sure the stuff is gone now.

At no point the the FC consumption ever act like anything was wrong. At one point there was enough gunk on the bottom that I thought it must have been algae, and I bumped up the FC's to close to shock just in case. It still averaged about 1 or less consumed on cool, unused days, though.

I think if it happens again I may try to use the flocculant (to REALLY settle it and get it all at once) or DE in the filter (if I can find it.)
 
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