Why won't my pool get clean?

[rilesworld]

I recently bought a house with an IG vinyl lined pool. This is my first year maintaining the pool. This may be a silly question, but I am having trouble getting my pool clean (it's clean, maybe I should say sparkling). We have had quite a bit of silt, pollen, leaves, etc. in the pool this spring, and we vacuum about once a week. However, everytime I get done vacuuming some of the silt seems to return the very next day. Is this silt that just gets suspended during the vacuuming process (stirred up) and then settles back down the following day? Is that typical? I try to be careful and go slow, but sometimes I have to scrub to get the silt up.

My other thought was that I am actually vacuuming up the silt, but it is just not getting filtered out and then ends up back in my pool.

Riles

[matt4x4]

if you have to scrub a bit to remove teh "silt" then I highly doubt it's settled silt - please read:
http://www.poolforum.com/pf2/showthread.php?t=6954
it should explain what you should do.

[rilesworld]

I have read that post before, and was curious about that type of algae. Is there anyway to determine whether it is silt or algae (without a microscope). I would hate go through the extreme shock process if it wasn't necessary.

BTW I have a couple of other points. The bottom of the pool does feel a bit slimy (bad news), but this hasn't seemed to get any worse over the past month with me maintaining 3-6ppm Cl. It just won't go away. In other words, I don't get the impression that anything is multipling. Not sure if that information is useful, but it might help.

Riles

[mohawk]

We've had this same stuff since the pool was installed last year. I always thought it was dust and dirt. We had to dig out around the pool last year for code and now the grass is finally growing in, but I still get this dust the day after I vacuum. I thought maybe everyones' pool was like that. What can I say, I'm a newby. I still have a bottle of polyquat from last year. Do you think I should try that? I don't want to fade the liner. Right now I'm trying to get my CYA up since I had to drain this spring cuz of a hole. I always thought algae stuck on pool sides-that's what it does in my aquarium. Denise

[rilesworld]

The more I think about this the more I believe that it is indeed some form of algae. I do have a fair amount that clings to the walls and it is typically found in the low flow areas first.

I vacuumed yesterday evening and this morning brown deposits again could be found throughout the pool. Not a huge amount, but it has definately redeposited to some extent.

I am going to go ahead and shock as Matt has suggested and I will keep you posted with what I find out. As I said, I have had this issue for about a month, so if it clears with some heavy shocking then I can feel certain that it was indeed some form of algae.

Riles

[ivyleager]

Slickness on the vinyl surfaces ALWAYS means you're working on something growing in your pool. That's my first clue that I need to shock, which I do only rarely. Check your pool chemistry to make sure your levels are in range (CC, CA, TA, pH). If so, try these three things to sparkle up your water: 1) superchlorinate anyway to levels required based on your CYA, 2) run your filter 24/7 for the shocking, then knock it down to slightly over what you need to turn your water over; 3) use a skimmer sock ALL season. If you don't mind running the filter longer go ahead. I run mine from 8am - 6pm. I don't split up the time or need to run it at night. I'm not in California so that's not an issue. My pool ALWAYS sparkles. When it doesn't, then I know I have a problem.

Hope this helps.

CaryB
Anyone but Buffalo

[mohawk]

I've been thinking - if I add polyquat to the pool before vacuuming and the brown goes away, then I should assume it was algae-right? Then vacuum afterwards.

[chem geek]

To all posting with pool issues (rilesworld, mohawk): please post a complete set of numbers including FC, CC, pH, TA, CH, CYA. Otherwise we are really shooting in the dark here. The CYA level is very important to know as that will tell us how much chlorine is needed to battle this algae.

As for PolyQuat, it is generally not as effective at killing larger amounts of algae as it is for preventing algae from taking hold. This may be from this chemical polymer being easy to clump free-floating algae particles together and to block their ion channels, but that PolyQuat may be unable to penetrate below the surface layer of a biofilm of existing algae.

Richard

[tphaggerty]

I have had the slickness with my vinyl pool in the past. From my experience, you don't always need to "shock" (or super-chlorinate) to get rid of it, but you do need to BRUSH. Someone above posted that they get this in the less well circulated areas of the pool, and I think that is a good clue.

If you maintain your CL levels (meaning it is pretty steady, not dipping to 0, then back up), you can normally get rid of any slimy or slick feel by brushing the walls AND floor. If the feeling returns, you may need to shock and/or increase your normal CL levels a touch.

Richard has posted many times about CL not being as effective on bio-films (until they are removed) and I think this is a thin bio-film of algae. Once it is scrubbed/brushed a bit, the CL can get right to the vinyl and should keep it away at your normal levels.

[rilesworld]

My numbers were as follows before I shocked:

FC - 4
CC - 0
Ph - 7.5
CYA - 40
TA - 90
CH - 190 (not sure about this one, but I vinyl so I don't test it often)

I went ahead and shock to 23 ppm just in case I was battling the Yellow/Mustard algae that Matt4x4 refers to.

My Ph did go up quite a bit with the shock is that normal? It reads about 7.8-7.9 right now.

I brushed and added some DE to my sand filter. I already seems to have helped. Although I won't really know whether it was shocking or the DE that solved my problem. I guess I don't really care at that point.

What is a safe chlorine level to swim at?

Thanks,

Riles