Slightly cloudy with brown residue at the bottom

[proximo]

Since I found this wonderful forum almost a year ago I've been following the BBB method and it has really been great! Most of the time the pool is very clear and my costs are low to maintain it. I use the Taylor K-2006 kit for testing. I added Borax to help prevent alge last year. I don't shock weekly like I used to since I've learned here that it's not necessary.

My setup is a 36,000 gallon vinyl pool with a Hayward 1.5 hp pump (I know, it's oversized) with a Hayward sand filter, and a Tri-chlor feeder.Here is a typical reading of the water over the last couple of weeks:
FC: 7
CC: 0
PH: 7.4
CYA: 55-60
TA: 150 (well water is high)
Temp: 90°

My problem is that the water occasionally looks cloudy in the deep end. I especially notice it after brushing (try to do this weekly). After a few days to a week it clears up. Also I constantly have some brown residue at the bottom - mainly on the edges and corner. I know this is dead alge - possibly mustard alge. I've been dealing with it by vacuuming it out to waste since it passed right through the sand filter. I've tried shocking it out last year but I may not have done it right. Also I am vigilant and make sure the chlorine levels never drop below the minimums so I'm not sure how alge could have gotten in.

Any suggestions on what I should do would be appreciated. Thanks!

[Charlie_R]

Try and capture some of it when you vacuum. Maybe fill a bucket with the waste as you vacuum. Let it settle and try to smear a little of it on a white surface. If there is any green or yellow to it, then it probably is an algae.

Have you been noticing an abnormal usage of chlorine? Perhaps you should temporarily shut off your feeder and dose by hand for a weekend to check your demand.

[proximo]

I collected some of the residue with an ear bulb thingy and placed it in a jar. When it settled I poured the water out and took samples. I placed these on paper and attempted to smear them. It looked brown and the texture of sand. I suppose it could just be sand from the filter or dirt that made its way into the pool. Is there anything else I should check?

What about the cloudiness that we sometimes see after brushing?

[PoolDoc]

I collected some of the residue with an ear bulb thingy and placed it in a jar

Good thinking!

Filter sand should be quartz (unless you've got some sort of filter goop in your filter). With a digital macro photo OR under a hand lens, you should be able to see if the sand particles are quartz bits and crystals. Also, if you put bleach in the jar -- if it 'dissolves' or lightens the particles overnight, it's not real sand.

What about the cloudiness that we sometimes see after brushing?

What sort of pool surface do you have? Painted concrete? If so, it's just epoxy chalking (that's how it wears!).

[proximo]

A couple of days ago the cycle repeated. I came out and noticed a yellow film covering most of the bottom of the pool. We brushed the sides and bottom (it's a vinyl pool) and again got a very cloudy pool (can't see the drain in the deep end). Water looks yellowish. I'm running the filter constantly to try to clear it up. Also went ahead and raised chlorine levels to shock values (20) and cleaned behind the pool light (it was really gross).

Just can't figure out how algae is getting in there since my chlorine levels are consistent. I suppose this could be mustard algae rearing it's ugly head. Any other ideas I should try?

[proximo]

Pool water still cloudy a week later so I'm going to try to keep the chlorine levels at shock level and the filter going until it clears. Floor is now heavily covered by brown residue. Still scratching my head as to how this could have happened! I have kept chlorine at ~7ppm for weeks with the chlorine feeder.