Why won't my pool get clean?

[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

[chem geek]

Yes it is normal for the pH to go up when adding chloriniating liquid or bleach. As the chlorine gets consumed or breaks down from sunlight, the pH will drop back down.

With your CYA level, wait for the FC level to drop below 10 ppm though technically even 23 ppm FC with 40 ppm CYA is equivalent to only 1.4 ppm FC with no CYA (i.e. typical of what may be found in indoor pools that don't have CYA).

Richard