Brown gunk on the bottom of pool

[BigDave]

Your TA is fine at 80, If you pH isn't moving too quickly, I wouldn't worry about it.
I would add the rest of the CYA - you're still under 30.
You might want to bump your pH a bit with a little Borax ... but maybe not, do you find that you pH rises from using your SWCG?
You don't need to worry about CH in a vinyl pool - It's strange that your test doesn't work the way it should but ... I haven't done the CH test on my water 'cause it's meaningless to me. I suppose if my water was cloudy I might check.
Regarding the brown dust (and I don't know if this would help), I had a robot cleaner for three years I ran my Intex donut - it saved me hours as my yard is tree-covered. The filterbag is pretty fine - it might help - but $300 is a good price for one. It only lasted three years but I liked it so well I bought another this year.

[rox29160]

The lady at the local pool store sold me something to reduce the ph in pools when I went to get my stabilizer, but I have never had to use it. She said I would definitely need it with a SWCG and I didn't know any better than to listen to her. My ph has been consistently around 7.2 since I put the pool up at the beginning of the summer. It never seems to change. That is why I had thought about putting in some Soda Ash to raise the PH a little since is has always been on the low side. I think soda ash also raises the Alkalinity which would knock out two birds with one stone. I just don't know how much to put in. I definitely don't want to overdo it and through the whole thing out of balance.

The instructions for the K2006 test kit says if the CH test starts out purple then there are metals in the water, hence the reason for adding the titrant before the test to tie them up. PoolDoc seemed to think my brown stuff on the bottom of my pool may have been iron so now I am wondering if this proves it. If I need to get it out, what do I use and how much of it?

[AnnaK]

Sometimes, brown gunk is just . . . brown gunk. Our pools provide a very large surface area on which dirt collects: airborne dust particles, pollens, whatever. Not all of it gets swept into the skimmer and trapped by the filter. Much of it sinks and, in due time, makes brown gunk. I dust my furniture every so often without really giving much thought to what that fine grey layer of stuff is or where it comes from. It's just dust: dander, smoke, oils, the detritus of life inside a home.

Since you haven't had an active algae outbreak and your numbers look pretty good and your water is otherwise clear you could just accept the brown gunk as part of having a pool that gets dirty. Not unsanitary. Just dirty. I have those same spots in mine and I would bet they're pretty common. I vacuum occasionally, I brush other times, I use a skimmer sock. The fine debris comes back, sometimes overnight, sometimes it takes a few days. I look at it as my pool's circadian rhythm

[rox29160]

I just didn't have any of this "brown gunk" on the bottom for about the first two months the pool was open. Then after reading on here, I started maintaining slightly higher FC levels. When I raised the FC, it was almost overnight that the gunk appeared. I had never had algae that I know of so I don't think it is algae. The water has always been sparkling clear, but the brown dusty stuff on the bottom makes the pool look nasty. Vaccuming just seems to stir it up. The pool looks spotless after vacuuming b/c you can't see the brown stuff (it mixes back in with the water) I have no way to vacuum to waste since I have a venturi type vacuum with a debris bag. It goes right through the debris bag. My filter does catch some of it before it settles back out, but no where near all of it. It will start settling again within a day. Maybe you are correct that it is just normal "stuff", it just seems odd that it seems to increase with FC levels. It sounds as though I may just have to vacuum every day to keep it stirred up. Thanks for your help Anna.

[BigDave]

Since pH is stable, I wouldn't move the TA. I would, however, move the pH up a little with Borax, 7.2 is as low as you want to go leaving little room for it to drop. We've had alot of rain recently and my pH went from the high side of 7.4 to under 7.2 in one storm ( my TA dropped as well ). The rain consumed my margin and I was still in the safe zone - had I started at 7.2... You do have room with your TA so if you want to use Soda Ash ('cause you already have it?) then, sure, just do it a little at a time ( 1/4 cup to start ) - let it mix throughly and measure the result.

The Brown Stuff: Does it really bother you? Is it staining your pool?
If it is metals, you might get more when you raise the pH - watch for that. Is there more when the FC is higher?
Perhaps your observation in the CH test is good reason to have your water tested for metals.

[rox29160]

Thanks for the reply BigDave. I will pick up some Borax. I've been waiting all summer for my PH to go up like the pool store lady told me it would, instead of buying something else. I knew I was on the low side. We have had a lot of rain as well, which may be the reason my TA dropped from 90 to 80 and also the reason my PH has not been increasing. I do not already have Soda Ash so it doesn't matter to me which one. I just thought my TA needed to be bumped up slightly too and Soda Ash would do both. I'll stick with Borax per your recommendation.

The brown stuff is just a nuisance. It comes back every day after vacuuming. The water is clear but the brown stuff settles out to the bottom and makes my pool look dirty. Before anybody comes over, I have to hurry and go vaccum the pool.

[BigDave]

I supppose it's personal preference for me. I increase TA with Baking Soda and increase pH with Borax; seems to me it's more targeted - just my thinking, either way will work. BTW, it will take twice as much (by weight) Borax as Washing Soda to have the same effect on pH.
Swamp Mistress ( http://www.poolforum.com/pf2/showthr...-it-all!/page6 ) seems to have had luck with a series of improvised filters.

[AnnaK]

Maybe you are correct that it is just normal "stuff", it just seems odd that it seems to increase with FC levels. It sounds as though I may just have to vacuum every day to keep it stirred up. Thanks for your help Anna.

Each pool is unique and who knows why that brown stuff invades. You've reported clear and sparkling water and no CCs to speak of. Your pH is a smidge low but that's personal preference. It's 'in range' at any rate.

I know those patches of brown are unsightly and it is frustrating that they come back after vacuuming and/or brushing. In my pool, it only happens during late July/early August. When it's just us here at home, I toss the dogs in to stir things up. When we expect company I might vacuum to make it all look pretty but, more then likely, I'll just let the dogs swim for a while and scoop out the fur before the guests arrive.

Does the bottom of the pool feel squeaky clean? Not slimy? That's one of my hallmarks: a slimy feeling bottom heralds biological invaders and I might dump some extra chlorine in, regardless of what the test says. If the bottom feels clean then I'm going with Occam's Razor: sometimes, a kiss is just a kiss . . . and brown gunk is just part of the pool's life.

[rox29160]

Dave: Thanks, I had actually read somthing similar to that before about using batting and tube socks. I haven't actually tried it yet. I haven't figured out in my mind how to attach it to my vacuum so it works effieciently yet so I haven't tried it yet. I might just tie it on tonight and give it a go and see what it does.

Anna: Every thing has always felt squeaky clean. Mine did show up in late July so maybe it was a coincidence that it was right after I raised my FC levels.

[rox29160]

I made and improvised filter out of four old socks to use in combination with my venturi vacuum and debris bag. I simply put the socks, one inside the other, and tied them around the outside of the debris bag. I vacuumed all the brown stuff up a week ago and it still has not returned. (Previously, it had been coming right back after vacuuming. Most of the time within 12 hours.) The sock on the inside, the first filter if you will, was almost completely brown after vacuuming. The socks got cleaner and cleaner as you worked your way out.

I have added 3 cups of Borax so far and let it mix in for a couple of days each time. It has changed my ph from 7.2 to maybe 7.3. I added another cup or so over the weekend and plan on checking it tonight to see where my ph is now. It seems like I am having to add an awful lot. The Pool Calculator said I only needed like 11 fl oz to raise it to 7.5. I am now at around 16 fl oz. Twelve ounces hardly made it change at all. Maybe I did something wrong on the calculator. Anybody know how much I should have to add?