Pool dust or algae settling in floors

[3FootPool]

I run my robot every day and often more than once a day. No matter how much I run it, there is always algae settling on the bottom floors of my pool. My pool readings are normal and water is pretty clear and I run a sand filter.

Is there anything I can do to reduce the amount of algae / dust settling at the bottom of the pool?

 

[PoolStored]

How are you testing your water. Get a recommended kit if you don't have one. Link-->Test Kits Compared

If you have a recommended test kit, do this test tonight. Link-->Overnight Chlorine Loss Test

If you pass, it is likely dirt.

If you fail, follow the SLAM process to clear the pool. Link-->SLAM Process

If you don't have a test kit, add 3ppm of liquid chlorine per day until it arrives.

 

[3FootPool]

How are you testing your water. Get a recommended kit if you don't have one. Link-->Test Kits Compared

If you have a recommended test kit, do this test tonight. Link-->Overnight Chlorine Loss Test

If you pass, it is likely dirt.

If you fail, follow the SLAM process to clear the pool. Link-->SLAM Process

If you don't have a test kit, add 3ppm of liquid chlorine per day until it arrives.

I have a Taylor test kit.

My most recent readings were:
Chlorine: 4
pH: 7.8
Alk - 90
CYA- 30
CH - 200

What can you tell from the readings that would constantly cause all this algae settling at the bottom of pool? I assume the algae is dead right? Or is it alive and that’s why it keeps breaking out? The pool is clear but the dust or algae is very visible at the bottom.

I also add about half gallon of chlorine nightly to my 18K gallon vinyl pool.

I don’t see how it can be dirt either. That’s a lot of dirt and there doesn’t appear to be any way of getting that much dirt into the pool.

 

[PoolStored]

It is either dirt or algae. If it is algae, it is there because you didn't follow this, and allowed FC to get too low. Keep your FC near the high end of the range...Link-->FC/CYA Levels

Do this test tonight. Link-->Overnight Chlorine Loss Test

If you fail, SLAM. Link-->SLAM Process

 

[3FootPool]

It is either dirt or algae. If it is algae, it is there because you didn't follow this, and allowed FC to get too low. Keep your FC near the high end of the range...Link-->FC/CYA Levels

Do this test tonight. Link-->Overnight Chlorine Loss Test

If you fail, SLAM. Link-->SLAM Process

Thanks problem solved. The clarity is a TON clearer and I don’t see much dust anymore.

With my 18K gallon vinyl pool, how often should I expect to add chlorine? CYA is around 35 and I use liquid chlorine (10%). I typically add about half gallon a night. Seems like with half gallon I can get it up to around 5-6 ppm during the day and then it dips down to 3 ppm by nighttime. Does that sound right?

 

[KenKasza]

What did you do to fix it? Did you conduct an OCLT as recommended by @PoolStored?

 

[PoolStored]

Your CYA is 40, round up to the next 10. Follow this...Link-->FC/CYA Levels

Dose enough so that WHEN YOU TEST, you are in range. Min is LAVA.

 

[3FootPool]

Your CYA is 40, round up to the next 10. Follow this...Link-->FC/CYA Levels

Dose enough so that WHEN YOU TEST, you are in range. Min is LAVA.

What does LAVA mean? To be in range all the time, seems like I’d need to add a gallon a day. Does that sound excessive? Are there cheaper ways to maintain the levels such as tablets?

 

[3FootPool]

What did you do to fix it? Did you conduct an OCLT as recommended by @PoolStored?

I realized my chlorine was too low so I shocked it and all the algae on the floor cleared up as well as pool clarity significantly improving. I did the OCLT test this morning and lost about 1ppm but sun had already hit. So I plan to do it again tomorrow to make sure.