Still fighting brownish dust in bottom of pool

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FoxyRoman

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Nov 1, 2012
18
New Freedom, PA
I continue to struggle with brownish dust that keeps settling in the bottom of my pool. I've read through a number of posts from the last several years with members reporting similar problems, but the posts never seem to reach a conclusion where the silver bullet solution is revealed. The pictures attached by wkener2 in this topic (http://www.troublefreepool.com/what-is-this-brownish-dust-at-the-bottom-of-my-clear-pool-t35509.html) best depict my problem.

I began fighing the issue on 8/28 and brought my pool up to SLAM levels for several days, never failing to pass an OCLT. I even then raised it to Mustard shock levels. My water has remained clear throughout, but when I brust the bottom of the pool, this brownish dust poofs up and clouds the water until it resettles, generally in about 12 hours. I've added DE to my filter, but have had very little luck. Out of desperation, I even applied the pool store's recommendation of phosphate remover this past weekend (even though I was skeptical), vacuuming to waste on Sunday. Still, the problem persists. I once again SLAMmed my pool last night and passed another OCLT this morning. CC's are 0.

Has anyone had any final luck in ultimately getting rid of this stuff? I'll be closing the pool in a few weeks, but I really don't want to just have this same problem to look forward to in the spring.
 
You have never SLAMmed the pool to completion.

The SLAM process is complete when....
1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1 ppm.

Your pool water is not sparkling....the brown dust settling at the bottom fails that test.

I'd bet dollars to donuts that "dust" is algae and you are not holding your FC high enough long enough to eradicate it.

Follow the SLAM process to completion (which involves filtration, brushing and constant high levels of chlorine) and I'll bet your pool will clear.

Since you have apparently been having this issue for three years you need to change what you are doing or it will continue.

Can you post a complete set of current test results?
 

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duraleigh said:
You have never SLAMmed the pool to completion.

The SLAM process is complete when....
1. Your pool water is sparkling
2. Your CC's are .5ppm or less
3. You can hold your FC overnight without losing more than 1 ppm.

Your pool water is not sparkling....the brown dust settling at the bottom fails that test.

I'd bet dollars to donuts that "dust" is algae and you are not holding your FC high enough long enough to eradicate it.

Follow the SLAM process to completion (which involves filtration, brushing and constant high levels of chlorine) and I'll bet your pool will clear.

Since you have apparently been having this issue for three years you need to change what you are doing or it will continue.

Can you post a complete set of current test results?
Click to expand...

This is my first year with the pool. Was installed last fall. Was going along swimmingly :) with the pool maintenance up until 8/23.

FC - 19
CC- 0
PH - 7.4
TA - 80
CH 150
CYA - 50 (it dropped a fair amount with the backwashing and vacuuming to waste)

I guess I'm confused on the SLAM process. My OCLT passes consistently and my CC's are .5 or less. In my mind, my water is crystal clear, it's just that I have this sediment that keeps settling to the floor. If my OCLT is passing, can you give me more info on how I could still be fighting algae so I understand better? Are you saying that even with OCLT passing, algae is still active, just not registering via FC consumption?

I was also always under the impression that dead algae dust appeared more whitish/greyish. This is definitely a brownish/yellowish tint. Nothing forms on the walls or sides of the steps.

Very perplexed/frustrated. Thanks to everyone by the way for the questions/suggestions. This site is fantastic.
 
jblizzle said:
Also, what speed are you running your pump? If too high, that and sand issues could result in the lack of filtering.
Click to expand...

I've been running at 2500 RPMs at the advice of my pool builder. In his opinion, it's an ideal compromise between return circulation for skimming and filtering ability, but I'm certainly not married to it and open to suggestions.
 
If my OCLT is passing, can you give me more info on how I could still be fighting algae so I understand better? Are you saying that even with OCLT passing, algae is still active, just not registering via FC consumption?
Click to expand...

Yeah, that's pretty much what I think is happening. Dead algae is definitely brownish yellow and many things in your thread seem to lead to that probability. It is very common to have live algae that you simply cannot see in your pool but it becomes visible as it dies and accumulates in the low spots and crevices of your pool floor.

I cannot explain why your OCLT didn't indicate the presence of organics but visual indicators of your pool's condition are always the best. Your pics look like many, many pools on here (and my pool) with dead algae on the bottom.

Here's my suggested path....

1. Keep your FC up at SLAM value

2. Each time you see the dust, brush it up into the water so the chlorine can continue to work on it.

3. Run you pump 24/7, cleaning, backwashing your filter if your psi goes up 25%.

4. Vacuum when you can slowly pulling that dust into the filter.

Keep all four of those steps going until your pool floor is crystal clear just like your water.

At this point, I would test just once daily, returning the FC to SLAM value after each test. Don't perform the OCLT anymore until all that stuff is gone.

Don't buy any other "magic bullets" like phosphate remover......you are wasting your money.

A little DE is fine if you want to but it is seldom necessary to rid a pool of the debris you are seeing.

I don't know when it will go away (I suspect in just a day or two more) but, unless you can positively identify it as something other than dead algae and figure out the source, I would assume you still have some organics in your pool to get rid of.
 
I get brownish yellow stuff on the bottom too. It goes away when I vacuum then comes back over time. It's too fine to be filtered and it always sinks to the bottom soon after I stir it up. I think it's sand that comes in on people's feet. Do you have sand near the pool?
 
Hi Dave, I've also been struggling with this same problem at one of the pools I service. It's strange because I also service a pool two houses down and I've never had this issue. But I'm trying to understand how algae can be growing in that type if environment, he posted a FC of 19 with a CYA of 50? The pool I'm currently trying to diagnose is a 20,000 Gal with SWG and in the middle of winter I raised FC to 10 with a CYA of 40 and I'm still seeing this stuff every week!? I just don't get it?
 
i believe the original poster has sand that is channeled and needs to do a deep clean on the sand and remove the clumps. there is an easy way to determine this in my opinion. Vacuum the dust/algae/whatever out to waste and then shut the pump off for a couple of days. If the pool stays clean then you know that the filter is channeled and probably letting a little bit of dust through upon startup. If it is algae shutting the pump off for a couple of days would magnify (if anything) the problem.
 

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