I have this gray sand on the bottom of my above ground pool. Some of it is stuck to the vinyl and needs to be scrubbed off. I've seen other threads about this but I can't find one with my exact circumstances. I have a sand filter with a paper cartridge filter downstream of it. I had the volcanic sand in the filter from when the pool was new 8 years ago. The gray sand problem only started happening about a year and a half ago. I thought it was because the sand was getting old and breaking down and passing through the laterals but couldn't figure out how it was getting through the cartridge filter. BTW this sand is completely absent from the cartridge filter as well as the filter housing. I replaced the volcanic sand with silica sand 1 week ago. I removed the lateral assembly and checked it for cracks and damage, none found. The exact same gray sand is still collecting on the bottom of the pool. If it is from the sand filter, how is it getting past the cartridge filter and why is there never any residual sand in the filter housing? If it is not from the sand filter, then what the heck is this stuff? It isn't the same as the dirt from the environment around the pool, that dirt is brown. Any help would be appreciated.
Gray sand on the bottom of my pool
- Thread starter mdenbow
- Start date
- Jun 22, 2014
- 48,074
- Pool Size
- 17888
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- CircuPool RJ-45 Plus
I have to ask the obvious question .... are you sure it's sand? Have you collected some of it and felt it's texture? If you confirm it's sand, is there any possibility sand could get blown in from something nearby? Any concrete or grout areas perhaps?
If the substance is not gritty like sand, then perhaps it's algae and a full set of water test results would help.
If the substance is not gritty like sand, then perhaps it's algae and a full set of water test results would help.
I have not been able to collect any. I'm just going by what it looks like. I looks like granules about the size of sand. My water chemistry: Free chlorine-4, pH-7.6, Total alkalinity-65, Cyanuric acid-45. The water is crystal clear otherwise so I don't think it's algae or a chemistry issue. I tend to think it's coming from my filter because it's concentrated in the area of the pool where the water return discharges. I live in the desert. Yes we have lots of blowing sand but I've seen that sand in my pool. It's all over, not concentrated in one specific area and it is definitely different than this stuff. Sand from the wind is brown and when I vacuum it out, I can see brown dirt in my cartridge filter. This is gray like concrete color. There is no concrete deck around my pool as it's above ground. I have a patio but it's downwind and been there for 10+ years. This problem only started about 1 1/2 years ago.
- May 3, 2014
- 58,832
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
It kind of goes poof. If it is algae, it's like no algae I've ever seen before. It's concrete gray and looks granulated like sand. I keep the chlorine levels up in my pool regularly, so I don't understand how algae can ever start growing. But it is concentrated in certain areas of the pool. Newer above ground pools don't have a floor drain but only a skimmer with the return just a few feet away. This, to me, seems inadequate for complete pool circulation. Could it be that this problem, if it turns out to be algae, is caused by poor circulation? I will be changing my liner here in the next couple of years and I think I'm going to install a floor drain at the opposite end of the pool from the return.
- May 3, 2014
- 58,832
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
Floor drain does not help circulation all that much. Multiple return jets do, or in an ABG pool, directional jets help.
Most of the time really light debris that goes poof is dead algae. Yours might or might not be. Do you regularly brush the pool and get the material up into the water? Vacuum it?
Most of the time really light debris that goes poof is dead algae. Yours might or might not be. Do you regularly brush the pool and get the material up into the water? Vacuum it?
I don't brush it because of the lack of a floor drain. It doesn't get pulled into the skimmer, it just settles back to the bottom. I vacuum it out. I can get it all out, make sure my FC is good and 2 days later, it's all back, laying in the same area of the pool. I've shocked the pool several times, and within a couple days it's all back. I'm not saying it isn't algae, you may be right, but I can't seem to get rid of it no matter how much chlorine I put in. I've had this pool for 8 years and have never had this problem until about a year and a half ago. Something has changed somewhere.
- May 3, 2014
- 58,832
- Pool Size
- 6000
- Surface
- Fiberglass
- Chlorine
- Salt Water Generator
- SWG Type
- Pentair Intellichlor IC-40
If it comes back after a couple days, it really sounds like dead algae.
Have you done a Overnight Chlorine Loss Test? Completed a full SLAM Process?
Have you done a Overnight Chlorine Loss Test? Completed a full SLAM Process?
Do you have stairs? What is weighting them down? Perhaps a container of sand ballast cracked.
I'll take your word for it. Although I'm not seeing anything green in the water and it's clear to the bottom otherwise. I'm presently not in a position to SLAM it as that is a multi-day undertaking. Work is taking up all my time right now. All I can do is make sure the FC level stays up.
Just an update. I've completed that SLAM process and I'm keeping the FC levels at 3-5 ppm. The gray sand is still there. I vacuumed it all out yesterday and today it's all back. I don't believe this is dead algae. With the chlorine levels I've been keeping, there's no way algae can even start growing, much less grow and be killed in less than 24 hrs. It is a complete mystery to me as to where this stuff is coming from. When I open my cartridge filter, which is downstream of my sand filter, there's not one grain of this stuff in there, neither is it present on the filter. If anybody has ever seen anything like this, I would sure appreciate any insight you might have.
borjis
LifeTime Supporter
Any chance it is roof asphalt granules?
I get some gray sand every time I blow out my gutters. Even with the cover on I usually end up with a handful of it in the pool.
I get some gray sand every time I blow out my gutters. Even with the cover on I usually end up with a handful of it in the pool.
Could it be ash from the fires? I had quite a bit in my pool. It did look like gray sand where it would gather. Made a "puff" like algee, but gray when hit with the brush.
That's a definite possibility and could be contributing to the problem, but this "sand" was in my pool before the fires started. Although the air has been fairly clear over my house the last few days, the "sand" is still in there in the same quantities.
Do you have a picture?
Does the stuff have any yellow, green or brown color at all?
Does the stuff have any yellow, green or brown color at all?