Is this yellow algae?

[nnhrm]

Hi guys,

We bought this house last year and the pool has always had this stuff at the bottom. Sometimes it seems like it comes from the filter because we will vacuum it up and then the next day after running the filter overnight it will be back.

 

[amwillg]

Gonna go out on a branch and assume that you have a sand filter?
Possibly a damaged lateral with sand escaping

 

[Saturn94]

Or DE?

 

[MITBeta]

Or dead algae.

 

[proavia]

Tell us a bit about your pool and test kit... actually, put all that info in your signature so we can see it each time you post. That will better help us to help you.

Post a full set of current test results
FC
CC
pH
TA
CH
CYA
Water temp
Salt level (if using SWG)

 

[nnhrm]

Sorry about that, I'm new here.
Yes, we have a sand filter. That's interesting because that's the first thing we thought when we saw it. Thought it looked like sand.

Current test results

TC 5
FC 5
CC 0?
pH 6.8
TA 40
CH 250
CYA 0-30
Water temp -- not sure, it is 8 degrees celcius outside and hasn't been above 15 for about a week, and we aren't heating it

 

[proavia]

We don't give much credence to test strips or pool store results as they have been proven time and time again to be inconsistent. It would be best for you to obtain one of the recommended testkits - Test Kits Compared.

 

[nnhrm]

We don't give much credence to test strips or pool store results as they have been proven time and time again to be inconsistent. It would be best for you to obtain one of the recommended testkits - Test Kits Compared.

Ah okay. Yeah, I find them pretty hard to read in terms of the colours as well. Never really sure where I'm at.
Perhaps we will get it tested at the local pool store this week and report back.
Thanks

Edit: oh I miss read that - really? no pool store results. wow. okay. thank you!

 

[phonedave]

1) As others have said, invest in a good test kit - it is going to make a world of difference. Think of it this way, if you are diabetic you want to know your sugar is 134 so you can does accordingly. You don't want to say "this strip looks yellowish red so I think my sugar is between 110 and 140 so I will take some insulin". Same thing goes for your pool. With test strips all you have is a best guess.

2) Once you get a good test kit, if it shows it is not algae then it could be sand from your filter. I have a DE filter that occasionally does the same thing. I use a slime bag and it works wonders.

 

[nnhrm]

1) As others have said, invest in a good test kit - it is going to make a world of difference. Think of it this way, if you are diabetic you want to know your sugar is 134 so you can does accordingly. You don't want to say "this strip looks yellowish red so I think my sugar is between 110 and 140 so I will take some insulin". Same thing goes for your pool. With test strips all you have is a best guess.

2) Once you get a good test kit, if it shows it is not algae then it could be sand from your filter. I have a DE filter that occasionally does the same thing. I use a slime bag and it works wonders.

How would the test kit tell me whether or not it is algae? Is it to do with the combined chlorine levels or does it have a specific test for algae?
Thanks

 

[phonedave]

Ah okay. Yeah, I find them pretty hard to read in terms of the colours as well. Never really sure where I'm at.
Perhaps we will get it tested at the local pool store this week and report back.
Thanks

Edit: oh I miss read that - really? no pool store results. wow. okay. thank you!

There are two issues with pool store results.

Sometimes the person doing the test really does not understand the test, and they just "follow the instructions" - sort of. People have gone into two different pool stores with the same sample of water and received wildly different results.

I am not going to say pool stores outright lie, but they do have an incentive to sell you expensive chemicals, and if tests support that story ...... If you do go to a pool store keep that in mind when they tell you that you NEED clarifier, algae out, polyquat, and whatever other potions they try to sell you.

 

[phonedave]

How would the test kit tell me whether or not it is algae? Is it to do with the combined chlorine levels or does it have a specific test for algae?
Thanks

Good - no combined chloramines (Not combined chlorine) mean probably no 'infection' in your pool.

Total Chlorine (or Combined Chlorine) = Free Chlorine (Chlorine waiting around for something to do) + Combined Chloramines (Product of Chlorine attacking organic matter - it gets off gassed eventually)
no Combined Chloramines likely means no active infection.

Better - Pass a OCLT - Overnight Chlorine Loss Test.

Chlorine gets used up in two ways (basically) From UV rays (the sun) and from attacking organic matter
You measure your CL in the evening after the sun goes down, and then you measure it again in the morning before the sun comes up. If it has not changed (or changed 0,5 ppm or less), then you are good. If it has changed, then something organic is in your pool and consuming it.

 

[nnhrm]

Good - no combined chloramines (Not combined chlorine) mean probably no 'infection' in your pool.

Total Chlorine (or Combined Chlorine) = Free Chlorine (Chlorine waiting around for something to do) + Combined Chloramines (Product of Chlorine attacking organic matter - it gets off gassed eventually)
no Combined Chloramines likely means no active infection.

Better - Pass a OCLT - Overnight Chlorine Loss Test.

Chlorine gets used up in two ways (basically) From UV rays (the sun) and from attacking organic matter
You measure your CL in the evening after the sun goes down, and then you measure it again in the morning before the sun comes up. If it has not changed (or changed 0,5 ppm or less), then you are good. If it has changed, then something organic is in your pool and consuming it.

Okay, thank you. That’s very helpful.
just in regards to what people were saying about the sand - my partner says he looked in the filter and the medium looks more like clear glass than sand.

 

[Saturn94]

Okay, thank you. That’s very helpful.
just in regards to what people were saying about the sand - my partner says he looked in the filter and the medium looks more like clear glass than sand.

That sounds like some kind of sand substitute some people use.

 

[nnhrm]

That sounds like some kind of sand substitute some people use.

Thank you. One other thing I just thought of is that I seem to remember the stuff in the pool “dissolves” when acid is poured on it.