Stuff on Bottom of Clear Pool... Brown Algae??

Hello All!

Let me start by saying Thank You too all that run and contribute to this forum. I found this forum and sister site, Pool Solutions earlier this year, and recently converted to the bbb methods after 4 years of the local pool store standard of bags of shock and algecide once a week and them testing my water. I purchased a K-2006 test kit and am testing my own water now and love the MUCH improved water quality I am experiencing using the BBB method! I have been reading as much as I can on the two sites to get up to speed, but still a huge newbie to my new found hobby.

Anyway to my questions. My pool water is clearer than it has been in a long time, however I have had this stuff show up on the pool bottom this week that looks like dead algae, but with a dark green/brownish color. It appears in the morning only after I add maintence Sodium Hypochlorite (12.5%). I have been reading many post here about Brown/ Mustard Algae hoping this is not what I have. There is a post with a picture that I cant see yet, that I would like to look at. The confusing part to me is that my chroline levels seem to be in tact. They are as follows:

Last night before adding hypo (7/20/11): FC=3.0, CC=0.4. Added enough hypo (per pool calculator) to take FC up to around 6.0, couldnt test to get an actual reading as it was too late.

This morning (7/21/11 1+/- hr after sunrise): FC=5.6, CC=0.2, CYA=50, PH=7.4, TA=170.. didnt test CH, but CH was teted on 7-15-11 at 180. If I got to around 6.0 on 7/20/11, I had a drop < 1ppm overnight, which should indicate no algae.. correct?

This evening when I got home (7/21/11): FC=2.0 (yikes), CC=0.4. Added hypo to take FC up to 6, let circulate for almost 2 hrs, tested FC=5.6, CC=0.4

Gonna test in the morning to see if I actually have less than 1 ppm lose to FC

Chlorine usage doesn't seem out of line?? Very hot day with usage. Does it make sense that it could be brown/mustard algae with these numbers? Its been two weeks since it has been shocked, and I have had a few days of evening test of FC less than 3.0. Always add chroline to raise FC upto +/- 6 immediately. I think I am going to shock this weekend just to be safe, the question is how hard should I hit it?

Another thought is could it be metals settling out? I top off the pool with well water, which we have a decent amount of iron. At pool opening I add a quart of staintrine (as recommended by local pool store) to care of the problem. I havent gotten an iron test yet this year, but have not had problems in the past when tested. I thought I read a post by Ben that he said it takes a very high iron count before needing to treat, so dont know how valid this thought is. Just throwing that out there.

Second issue/question, TA = 170. Per the book that came in my test kit, that is above the recommended range. But I read another post by Ben that with a vinyl lined pool that it shouldn't be a problem as long as it is below 200?? Should I start the process of lowering it?

Pool Specifics 24ft Rnd w/ Deep End (estimated at 18,000 gals), new 1 hp pump with 100 lb sand filter (yes..i wish I would have found this community sooner, manufacture said its good to 20,000 gal) runs 3 hrs on....3 hrs off.

WOW.. Sorry for the long post, what can I say...i'm a newbie learning.

Thanks Again!

As an update this morning (7/22/11)... have small amounts of the stuff on bottom again... with none last night.
Levels this morning are FC=4.8 CC=0.4.

Thanks!

Really confused now.... brought fc up to 7ish this morning couldn't get actual reading before going to work.. got home from work today with no one in the pool today and had more stuff on bottom.... vac to waste.. tested water with results of FC 5.8 and CC at 0.2? Water itself is very clear and not losing fc?? However.... I did find an algae source in the pool that has been looked over (probably a newbie move) ..... the pockets on the back side of the ladder and inside the bottom step...Yuck... I assume this may be part of the problem? I took the ladder out and cleaned with straight 12.5% and toothbrush. Is there any way to keep back side of ladder clean with use of toothbrsh, or now that I have cleaned it the way I did I shouldn't have a problem?

Questions questions questions...

Thanks!
TAB

Have you had your water tested for metals? That might be a first step. Post back once you have it tested and somebody here can try and help you.

Welcome to the Pool Forum!

Thanks for the reply Watermom. I will get it tested tomorrow and post the results.

Thanks again!

Update 7/23/11

First off I want to say that if anyone is still doubting BBB method..you should not! As I mentioned in original post. I have had my AG pool for 4 years prior to this year. Always did the pool store recommendation and had ok water at best, put alot of differnt stuff (per their recommendations) over the years. Converted over to the BBB method about 4 weeks ago and could not be happier. Had to take a sample to the pool store to get metals checked and was told I had perfect water and that I was showing it off. All I could do was chuck inside. I havent had this clear of water since the day I had the pool filled. Thanks Again to everyone here for promoting the BBB method and keeping us newbies on the right path. But back the the issue at hand.

Water checked out with no metals (zero copper and zero iron), everything else is in line with my last round of full numbers (see original post). I checked FC and CC levels this mornig as follows: FC = 4.2 and CC 0.2, so it appears the stuff may be the start of algae.. more than 1.0 ppm drop overnight?? I had a verry small amount of brown stuff on the bottom again this morning. I am going to start shocking, and I presume I need to take FC up to 30 ppm to be safe???

Also the pool store told me phosphates are at 500. Should I be concerned with this?

Thanks!
TAB

With CYA of 50, your shock level would be 15, not 30. Don't worry about the phosphate level.

Will 15ppm take care of it if it was Brown algae? That is why I was assuming 30 ppm? If you don't think I have brown algae I will shock at 15 ppm. I just don't want brown/ mustard algae as I had a full breakout two years ago.... what a mess.

Thanks for the reply Watermom. I will.wait to see what anyone thinks about brown algae or not?

TAB

I'm assuming this is a liner pool? You don't want to go higher than the recommendations in the Best Guess Chlorine Chart with a vinyl liner for risk of bleaching it.

Sorry Watermom... Somehow I missed your last post until now. Thanks for the reply! Yes it is a vinyl lined pool. When you say Best Guess Chlorine Chart.. that does include the far right column... correct? If I read things correctly about brown/ mustard algae, you need to shock at above normal shock levels, or did I miss something??

Thanks for all the help and patience! So much information to take in.. but well worth it!

If it's mustard algae, hold the chlorine at 15 ppm for several days AND brush the pool thoroughly, to get rid of the algae. Mustard algae ranges from brown to yellow green, and is loosely attached to the pool walls. DEAD algae (or dirt from kids feet) can be tan dust that piles up and will blow away if you wave your hand near it in the water.

Thanks for the reply Ben! I didn't know dead algae could be tan in color, thought it was always clear-grayish color. Will see if the stuff blows away with the wave of a hand the next time I run across this. I shocked the pool up to 15ppm chlorine and held it there Saturday and Sunday (followed Watermom’s post (thanks Watermom) of 15ppm as I was still confused about the whole mustard algae, higher chlorine and the Best Guess Chart and not wanting to potentially bleach out my liner) and brushed several times each day. I passed the 1 ppm overnight drop test overnight Sunday/ Monday. I let the chlorine drift back down Monday since I passed the test and no one was home during the day to maintain a 15ppm chlorine level anyway. So far Monday after I got home and this morning I have not seen anything on the bottom of the pool.

While reading through the forums this weekend, I came across another possible explanation for the stuff.. pollen?? I have read several post about using filter socks to pick up finer particles in general.. not just pollen. I picked up a package this weekend and was amazed at what the sock is collecting that might of been falling out on the bottom along with the dirt you suggested.

Has anyone else had problems with automatic chlorinators causing circulation issues?? I have one I purchased this year before finding the BBB method =( and once I got my CYA up to my current level, I took out my chlorine tabs, but did not shut the valve. This weekend I decided to shut the valve completely, and appeared to notice better circulation within the pool after shutting the valve? Could this cause more to settle out onto the bottom of the pool as well??

Anyway all seems well at the moment. If the stuff comes back and it seems like it is more than dead algae, dirt, etc.. I will then have to figure out a way to keep chlorine levels up for several days as suggested.

Thanks again to all the moderators and participants of this great site!
TAB

Glad to hear things are improving and thanks for the update.

Quote:

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Has anyone else had problems with automatic chlorinators causing circulation issues??

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Yeah, lots:
+ Hayward inline chlorinators restrict water flow a LOT, but closing the feed valve on the chlorinator wouldn't change that.
+ Depending on how it's been piped, all offline chlorinators can cause problems by feeding air from one side of the pump, to the pump intake. Resultant problems are quite common, and reduced flow could be an effect. If this were the case, closing the feed valve would improve the situation.