Is it possible for algae to become imbedded in Diamondbrite?

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jdp39

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May 31, 2011
42
Charlotte County, Florida
In an older (15 or so years) surface we seem to have algae growth on the pool surface regardless of FC/TC content. In addition, it appears in vertical striations that are not consistent with eddies or "dead spots" in pool circulation. I brush the pool every day, vac in the evening.
They do appear and reappear in regular areas of the pool. Mostly mustard algae it seems (yellow) although some are darker.
Two questions come to mind:
1) At mustard algae shock value for a given CYA level how long should it take for minor, and I mean MINOR, surface mustard algae to be killed? Days? Weeks?

2) Water is sparkling clear yet this algae will appear on pool surface ONE DAY after shock value is reduced to target. Sometimes even ABOVE target value.

Thoughts?
 
Re: Is it possible for algae to become imbedded in Diamondbr

It should appear to be killed in only a few hours at regular shock level. But to really get rid of it you need 24 hours at mustard algae shock after it all appears to be dead and to brush and clean very throughly, including all pool tools, toys, and bathing suits.

Black algae grows into the plaster, but mustard algae doesn't normally do so. However if the plaster is especially old and pitted there can be cracks and crevices that can harbor algae.
 
Re: Is it possible for algae to become imbedded in Diamondbr

Black algae. Usually very spotty in pools here. Not broadcast over an area. I have seen plenty of it here but it usually is in node like spots.
Mind you, about two years ago we drained, chlorine and acid treated the pool surface. I mean we left straight 12% chlorine on the walls/bottom over two days and then gave a light acid wash before refill.
Does mustard algae present over black algae?
This pool has been at mustard shock for three days, just coming down to target now and we have mustard growth.
 
Re: Is it possible for algae to become imbedded in Diamondbr

If I am interpreting your post correctly, those are Fridays test results and you allowed the FC to come down on Friday.

Bring the FC back up to shock and keep it there until....
1. Your water is crystal clear.
2. You lose less than 1.0 FC during the FC overnight loss test
3. Your CC's test is .5 or less

Essentially, algae will not exist in a pool with adequate chlorine. If you have algae (and it may not be algae, do you have a pic?), then the chlorine level is or has been inadequate.
 
Re: Is it possible for algae to become imbedded in Diamondbr

>> Water temp is 82F and in full sun all day

270 kilometers south of your location, I've cleared several local pools from various types of algae by running pump 24 hr/day, new filter media/cartridge/sand and maintaining FC at shock level, CYA at around 50-60, pH at 7.2-7.3

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Re: Is it possible for algae to become imbedded in Diamondbr

Those results are from this morning. Had been at 24-25FC from Wed til Fri. Water IS crystal but growth still coming back - not in the water but on the pool walls. After shock it was brushed, vacuumed and filter cleaned. Repeatedly. No trace of algae anywhere in pool and water was and is crystal clear. Once FC dropped below shock value mustard algae began to show up on pool wall again. As the pool was clean last nite I did not ck FC until this morning because I was trying to get it back to balance level. I will ck it again this afternoon to see what drop was during the day.
At 15FC w/ CYA at 50 should still be above target correct? Shouldn't that be high enough
to kill it faster than it grows?
Anyone know for that CYA level what chlorine consumption would be in full sun?
Perhaps it is something other than mustard algae, I will try to post pics later on but at this time of day it is difficult to get them. I can say that it dies readily at shock level and brushes off.
Thanks all.
 
Re: Is it possible for algae to become imbedded in Diamondbr

Did you take it to 30FC? I'm wondering if you hit mustard algae shock level.

The CYA test is subjective, so maybe a slightly higher shock level is correct.

I feel sure you did this, too - just checking: It is important to brush everywhere, wash bathing suits, and clean pool toys with diluted bleach solution or soak them in the pool for a few hours at the extra high shock level. Mustard algae can hide out in various places, even if they are dry at the moment.

Well, we'll see the test results Jason asked for and go from there.
 

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Re: Is it possible for algae to become imbedded in Diamondbr

Complete testing this morning virtually duplicated yesterday's results so for those numbers please see above. Since there has been no drop in FC or a rise in CC I am at a loss for algae growth.

As far as toys, bathing suits, etc. there are no toys and nobody has entered the pool since last week. In addition the filter was also washed in chlorine solution to eliminate that possibility. The pool cleaner and hoses received the same treatment. Once they were put back in service the pool water was still at shock value as well.

Old though it may be the surface is not especially pitted. However, since those pits would be in contact with the shocked water I am not sure I understand why algae would live while in contact with it. How does algae "hide" from chlorine it's in contact with?

I do agree that CYA tests are subjective though there is a much greater margin of error at the high end of the scale and less at the mid/lower end. Keeping this in mind I try to err to the side of caution and if my test shows 45 I use 50 as my number (as I have done here). Unfortunately even with a Taylor dpd test you must use a multiplier at those FC levels and anything over 25 FC is a guess. You can't be sure what it is, just that it's off the 5x scale. The dilute we're using is distilled water. I suppose I could get silly about it and use a burette but measuring pool water in grains is a bit over the top.

Attached is a photo of what has accumulated since Saturday. Area in question is slight yellowing at radius of pool bottom to side from light left to step. This was not present on Friday. Keep in mind test results from last two days. You will note the clarity of the water as well. Pay no attention to date as wife swapped battery ; ). I hope the photo helps. Beginning to believe it is something other than algae or some nuke proof version of it. In the interest of being thorough I think we should bring the water back up to over shock level for a couple of days and see what happens.[attachment=0:q5yasece]Pool Pic Resize 1.jpg[/attachment:q5yasece]

Your wisdom and info is greatly appreciated.
 

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Re: Is it possible for algae to become imbedded in Diamondbr

jdp39 said:
Old though it may be the surface is not especially pitted. However, since those pits would be in contact with the shocked water I am not sure I understand why algae would live while in contact with it. How does algae "hide" from chlorine it's in contact with?
Click to expand...
Water flow goes to zero when it reaches a surface so if there is any pitting or uneven surface then the water in those wells/pits will only get chlorine into them via diffusion which can be slow. Any algae that does end up growing there can form biofilms more readily as well unless you are brushing enough to dislodge them. Shock levels of chlorine increase the diffusion rate, but brushing is also key both for physical removal and for better mixing/circulation.

If what you are seeing is just a yellowing, then that might be metals and not algae. I've got an area in the deep end of my pool where the plaster gets a yellowish cast when the pH rises to around 7.8 and especially 8.0. When I lower the pH, the yellowing fades. That's pretty much a sure sign of a metals problem and I know I've got some rusting (stainless) steel mounts that introduce iron into the water. You might just see what happens if you lower and raise your pH with respect to the intensity of coloration.
 
Re: Is it possible for algae to become imbedded in Diamondbr

Without getting into hydraulic pressures at a given depth I take your point. As these spots are in deeper (near the bottom) and not shallower (near waterline) I believe hyd pressure would overtake flow, presuming by "flow" you mean circulation. Comme ci', comme ca. Laminar vs. turbulent, etc. Just watch that turbulent flow Geek. The worse the surface the more it becomes a factor........

I do think you're onto something w/ PH. We have tried in the last hour to brush those areas to no avail. My brush is my friend. PH has come up to almost 8.0. FC still constant at just about 15. So no loss thru use there.
Think we'll knock the PH down to around 7.5-7.6 and see what happens when the lights go on. Too bad we don't have any mounts to give an indicator. Anodes anyone?

Thanks Geek (and everyone else) for your unending support and knowledge here.
 
Re: Is it possible for algae to become imbedded in Diamondbr

jdp39 said:
Without getting into hydraulic pressures at a given depth I take your point. As these spots are in deeper (near the bottom) and not shallower (near waterline) I believe hyd pressure would overtake flow, presuming by "flow" you mean circulation. Comme ci', comme ca. Laminar vs. turbulent, etc. Just watch that turbulent flow Geek. The worse the surface the more it becomes a factor........
Click to expand...
I presumed you didn't have returns mounted low or pointed downwards causing significant circulation of water near the bottom. Many pools have rather poor bottom circulation so that diffusion rates become more of a factor, especially very close to the surface of the plaster and inside the pits/crevices. If circulation at surfaces was always excellent, then we would probably never need to brush our pools. Anyway, see what lowering the pH does.
 
Re: Is it possible for algae to become imbedded in Diamondbr

Never understood why most pool builders did that although I think Anthony & Sylvan had a whole pool circulation concept which I haven't seen catch on in the rest of the industry.
Anyway, lowered PH to 7.4 last nite and let pool run overnight. Discolored areas still visible. They are more visible to the eye than in pic unfortunately. Certainly not worse but not significantly better either. TC still hovering just under 15 and the rest of pool looks good. Could be a metal (or other) stain - brushing still has no effect. Copper or iron maybe........? I'll ck for info/threads on this.

Any reliable methods to determine what stains are? I know there are stain id kits out there but not sure if they're worth the package they're in.
Thanks again
 
Re: Is it possible for algae to become imbedded in Diamondbr

>> Any reliable methods to determine what stains are?

did you already try a vitamin-c tablet on a sample area? take one or two 500mg solid tablets and place them inside a pvc sprinkler end cap (the goal here is for the tablets to stay in one place and not float or move due to circulation) and place it over the area tested.
 
Re: Is it possible for algae to become imbedded in Diamondbr

I get the ascorbic acid but could you be a bit more clear on methodology. Unsure of what a pvc "sprinkler end cap" is. Do you mean to use a length of pipe w/ perforated cap to hold tabs in place whilst they dissolve?

Edit: I am unsure of what stains are. We have no source of metals in system nor in fill water that I am aware of. Might be trace Fe in fill water (well) but really need to ID stains.
 
Re: Is it possible for algae to become imbedded in Diamondbr

I have simply used vitamin C tablets crushed and placed in an old sock, then put a weight on the sock to hold it on the stain.
 

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