Mustard algae? pollen? at wits end...help please!

[mxfan]

I have been dealing with this issue for the last two years (on and off).

Our pool is going on our 3rd Summer and the first year was great. Ever since I have had some black algae issues and luckily with all the good info that I read here on the forum, I finally got a handle on it (black algae).

My problem is now that the water is clear and looks pretty good, but when I brush the sides of the pool I get this major dust that comes off the walls and is especially bad in our grotto/cave where we have bench style seats. If I brush the walls at all it clouds the entire pool to the point that I cannot see the bottom and is a greenish color.

Our pools is a sculpted cement pool that looks like natural rock. The sculpted cement goes all the way to the pool floor and looks really nice but it has a pretty rough surface. Some parts of the walls have a fairly rough texture and the bench seats in the cave also are the same style and it is a bumpy surface. The surface is similar to a real rock, but a bit rougher with some 'pockets' that are probably 1/16" deep or so and it makes a nice hiding spot for all the 'dust'.

I have tried to use a vacuum hose (from a skimmer) to catch some of the 'dust' while I brush it but it is pretty much a losing battle

I think it is actually a fine enough powder that it goes through the filter and comes back through the returns? but i'm not sure.

I have tried to look at the captured 'dust' under a microscope but I don't have a good one and it is not clear if it is a plant form or solid.

Part 2:

Our pools surface during the building process is poured and sculpted, sealed, than plastered and stained. Before staining they sprinkled some 'greens' and 'oranges' powder to color the cement and make it look more like real rock. (think natural swimming hole in a river).

The walls when they have a lot of the 'dust' on them, I can run my fingers down the walls and my fingers have the 'greens' and 'oranges' and browns coloring on them? It does feel slimey?

My pool builder also told me NOT to use acid in the pool...but i'm not sure if the acid could eat through the 'coloring' or not.

If I let the water in the pool settle for a few days it comes back to clear again, sometimes up to 3 days, and it doesn't seem to be using a bunch of chlorine on a daily basis. Daily use has been up to 3 ppm per day (I usually have it at 7-8 ppm) and lately it has been using less and less and for the last week or two has only been losing maybe 1 ppm per day.


My test #s from earlier today:

FC 6
CC 0
PH 7.2
TA 40
CH 190
CYA 60

water temp 80

I am at my wits end and am about ready to turn it into a coy pond :grrrr:

Any help, opinions on this would be much appreciated.
Thanks.
...Eric

 

[reebok]

would love to see pictures of that pool (and the dust if you can). you have a tf-100 right? you can preform the overnight fc loss test to see if you've got algae.
pool-school/overnight_fc_test

 

[dattia]

I'll second that reply! It sounds like you have an extraordinarily beautiful set up, MUCH too nice for Koi!

Those 'in the know' here will have you right where you want to be before too long... unfortunately, I am not one of them. Good luck!

 

[Butterfly]

Wow, your pool does sound amazing. It also sounds like the surfaces will make it difficult to deep algae at bay.

Have you done an Overnight FC Loss test?
It sounds as tho you are on the brink of a major algae outbreak. When you brush the pool it clouds the entire pool, can't see the bottom and is greenish color.

The walls when they have a lot of the 'dust' on them, I can run my fingers down the walls and my fingers have the 'greens' and 'oranges' and browns coloring on them? It does feel slimey?

The colors are coming off on your fingers? Maybe call the PB on this one?

How often is the pool being brushed? Esp the grotto area?

Do you use skimmer socks/screens?

 

[duraleigh]

The nature of your pool walls will always be a haven for algae.

Your posts back from last Summer indicate you have had a constant battle with algae. There is a 97% chance that is the battle you are facing again.

Constant circulation (pump 24/7), frequent brushing (with something long-bristled to expose the algae to the chlorine, and, most importantly, higher levels of chlorine (7-10ppm) that must be constantly kept in your pool will probably eliminate 90% of your issue but the walls themselves seem like they are a haven for organics to get established and hide.

Short of the koi pond idea, a regimen of chlorine, chlorine, chlorine is your best bet.

 

[mxfan]

Thank you all for your replies :-D

I did a FC overnight test and lost only .5 telling me that it isn't an algae issue?

I brushed about 1/3 of the pool yesterday and it went completely cloudy so I filtered all night and this morning it has all settled again and looks clear.

I have tried the skimmer socks in the past with some success but not too much.

I am thinking of pressure washing the remaining parts today (I haven't tried the pressure washer yet) but I am thinking it would be easier than brushing all the nooks and crannies.

After I normally brush a small part of the pool and wait about an hour I can try the same spot again and get a significant amount of dust again, like it just settles back into the walls for some reason. I never see too much on the floor of the pool? but maybe my pool sweep is taking care of some of it?

Thanks again for your help.
...Eric

 

[mxfan]

Here are some pics of the pool. The first is how it looked this morning after filtering all night, it is probably about the fastest it has ever cleared back up? I couldn't see the bottom yesterday at all after I had brushed about 1/3 of the pool.

The second pic is of the wall texturing itself to give you an idea of the surface roughness.

The 3rd pic is after brushing a small part of the wall (this is about 1/4 of the amount of 'dust' that comes off of the grotto seats) but the grotto is always the worst I think due to the fact that there is no skimmer in it and it seems to accumulate the majority of the leaves/floating stuff.

Thanks again.
...Eric

 

[mxfan]

Well I tried the pressure washer, but it didn't work so good, so I went back to brushing. After only about 30 minutes of brushing I had to stop because I literally couldn't see 2' in front of me and couldn't see where I had been or anything.

I snapped a quick picture of it after brushing (back to swampland!)

I'm stumped and am giving up for the day to try to enjoy the rest of Father's day :|

...Eric

 

[reebok]

man that is one cool pool. that last picture does look like algae to me...but you are losing less than one ppm of chlorine overnight... I'm sure someone else will have a better answer, but you could put some of that water in a container and see if bleach kills it.

 

[frustratedpoolmom]

Very confusing. An overnight loss of less than 1 would indicate this is not algae. Also I don't think algae would clear up with just filtration and settling, if you weren't shocking it would look like the last photo all the time, if not worse. It wouldn't just settle and clear the water without shocking the pool.... would it? The photos I've seen of full blown algae blooms look like the last photo, they don't clear up on their own.

 

[Butterfly]

What test kit are you using?

Your pH, TA & CH all look low.

What is your chlorine source?

 

[mxfan]

I am using the Taylor 2006 test kit.

I am using 12% chlorine and sometimes (if I run out) I use the 6% bleach as recommended. I also occasionally used the pucks in the skimmers when I was losing FC, but don't have any in at the moment.

I checked the pool again tonight and it is about 70% clear again and the FC reading is the same as when I tested it early this morning, 7 ppm.

...Eric

 

[frustratedpoolmom]

I'm not sure what's happening here. In the one picture the green spots on the walls - is that dye/pigment, or is that algae spots?

You are certain of your FC testing? You are saying you lost no FC all day - though the pool was not covered? And you are certain your overnight tests also you lost no FC?

Your ph/ta are low, and so is your CH. I don't know if long term if this is wreaking havoc on the rock, or how long your chemicals have been this way. You have a scale line or water line too, which doesn't make sense to me given your results.

 

[Buggsw]

Wow! That is one interesting pool design. Sure looks cool. I'm as stumped as everyone else. You said, when you run your fingers across the area you are getting brown, orange, green dust on your fingers, which is the same colors of stain. It almost seems as though the stain is "powdering" off. Your ph and your ta are on the lower ranges. I wonder if that is causing the stain to leach out of your faux rocks.

 

[frustratedpoolmom]

Wow! That is one interesting pool design. Sure looks cool. I'm as stumped as everyone else. You said, when you run your fingers across the area you are getting brown, orange, green dust on your fingers, which is the same colors of stain. It almost seems as though the stain is "powdering" off.

Thats what I was thinking about...if this is some kind of corrosion....

 

[mxfan]

Thank you for your replies!

The green and orange coloring in the photo is the coloring of the cement. During the process they plasters then sprinkled the green and orange powder around and then stained it (I believe). It has been 3 years so i'm trying to remember the process.

I'm pretty confident about the FC testing...unless I am out to lunch on my method? I fill the tube to the 25 ml mark than add a scoop of the powder until it turns red/pink than count the drops (around 14 which equals 7 ppm?) I think this is the right way...unless my chemicals are out of date? or something strange? I have had the kit for about a year and a half, and have also gotten some replacement chemicals for the kit as needed.

Our PB turned out to be pretty flaky near the completion of the project and I don't think I can chase him down (not easily anyways) so I am trying to find alternatives. I am actually meeting with another pool builder tomorrow (the guy I should have had build the pool) and although he doesn't do the 'sculpted cement' style pools, he is very sharp and i'm hoping he can shed some light on the situation. I am at a point that I might have him re-do the bottom and see if he can cover the existing rough walls of the pool with pebbletec?

I really don't want to do it...but if it will make the maintenance way easier for the next 20 years of so I might consider it.

Don't know what to do at this point, but I really do appreciate any ideas and the replies that I have received so far. thanks again!

...Eric

 

[Butterfly]

Eric, here's a link to PaulR's Testing Guide: water-testing-instructions-on-one-page-t11306.html

You fill the bottle to 10 (not 25) and then multiply by .5 (or just divide in half).

If it took 14 drops to clear using a a 25 ml sample, your FC is 2.8, which is way too low for your CYA.

 

[chem geek]

Eric,

If the powder is algae, most likely yellow/mustard algae if it is indeed algae, then it's possible that the chlorine usage is localized given that the circulation appears to be rather poor. Was the overnight test done in the area where the powder occurs rather than in the clearer areas?

However, your initial post numbers in this thread result in a saturation index of -1.0 which is indicative of dissolving calcium carbonate so would not be good for your cement pool. Since your cement is colored, the various colored dust could just be your cement dissolving into your pool and the colored portions entering into the water. Is there a particular reason you have such a low pH, CH and especially TA combination?

I would first adjust the water chemistry and then see where things stand. If it does turn out that you do have algae, then if this is a persistent problem due to poor circulation and a very textured surface, then either a higher chlorine level relative to CYA or a supplemental algae inhibitor would be needed. One algae inhibitor would be 50 ppm Borates in the pool. It's a one-time addition as opposed to having to use PolyQuat 60 regularly or maintain a much higher FC level, say 15% of CYA level. I can't tell you the specific FC % of CYA needed if you use the Borates -- that's something you'll have to experiment with.

Richard

 

[mxfan]

Butterfly,
Thanks for the post. I went and looked at my test kit (which I should have done before posting my FC testing method) and I do fill it to the 10ml mark not the 25ml. I was going by memory, my goof.

Thanks.
...Eric

 

[mxfan]

chem geek,
Good information in your post, thank you.

I test the water in the same spot each time...I will try different areas and see if it is any different. Most of the pool has about the same amount of the 'dust' on the walls with the exception of the grotto which due to the poor circulation in there it seems to accumulate more of the dust, and it also has the bench seats (horizontal shelves) that would seem to 'catch' more of the settling 'dust'.

As far as the low #s on the original test, they are not low on purpose or for any particular reason. I have a pool service that I use and don't normally check anything other than the FC and PH?

I am meeting with my pool service guy this week to show him the 'dust' when you brush the pool. If you normally walk up to it (if I haven't stirred it up by brushing) the pool looks really clear and the FC #s are usually in a good range? So I will ask him why the numbers are so low when I see him.

thanks.
...Eric