Mustard Algea or just dirt/pollen?

[Doddsy]

Hey all,

First post on this great website. I have been a covert to the TFP system but I have this ongoing problem (or maybe it isn’t one).
I have a small (30k litre) fibreglass SWC pool in Sydney Australia and I keep getting deposits in the bottom of the pool that looks brown and puff away when touched (see attached photos).
I did an overnight loss test and FC dropped less that 1.
Other stats:
FC 6 (I am letting it drift to 3 as per SWC recommendations)
PH 7.6
TA 75
CH 350
CYA 70
BOR 23 (waiting for more boric acid to arrive)

I have previously taken FC up to mustard shock levels for 24 hours (with lower CYA), lots of brushing but it came back. I have no automatic pool cleaner and manually clean once a week.
Is this actually an algae problem or just normal dirt /pollen that I should except and needs to be cleaned. I am thinking it’s easier to see dirt/pollen in a fibreglass blue pool.
Thanks for your help!

30k litre, fibreglass, Davey Promaster pump, Davey Sandfilter, Zodiac SWC, Clear Choice Labs Testing kit (FAS-DPD).

 

[Rancho Cost-a-Lotta]

It looks like dirt to me. Mustard algae is more yellow in color and would stick to the sides of the pool. Pollen would float or stick to the tile at the waterline. Is there a dirt source nearby?

 

[mknauss]

Your FC level is quite low. Your target should be 7.5% of your CYA, or about 6 ppm. See FC/CYA Levels

 

[Doddsy]

Your FC level is quite low. Your target should be 7.5% of your CYA, or about 6 ppm. See FC/CYA Levels

Thanks you right. I’ll keep it between 4-6 as per TFP recommendations.

 

[Doddsy]

It looks like dirt to me. Mustard algae is more yellow in color and would stick to the sides of the pool. Pollen would float or stick to the tile at the waterline. Is there a dirt source nearby?

Yes there is a garden bed around pool. I am surprised there is that much settling at the bottom all the time but must be windy. But your right it’s wrong colour. Also never on sides or floating.
I thought maybe algae couldn’t stick to side of fibreglass pool.
Thanks for your help!

 

[CRAD_oz]

Doddsy
I had the exact same problem with my FG pool. I have garden beds all around my pool and heavy rain was washing dirt into the pool. The only way to get the dirt out of the pool was to manual vac to my cartridge filters or to waste. Now I have a Robot cleaner with Ultra fine filters and now no more dirt!

 

[Doddsy]

Doddsy
I had the exact same problem with my FG pool. I have garden beds all around my pool and heavy rain was washing dirt into the pool. The only way to get the dirt out of the pool was to manual vac to my cartridge filters or to waste. Now I have a Robot cleaner with Ultra fine filters and now no more dirt!

Thanks, which robot did you get?

 

[CRAD_oz]

I have the s200. Not only was it well recommended on here but it came with everything I wanted and nothing of what I didn't want. The Ultra fine filters are perfect for the fine dust/dirt that collects in my pool.

 

[Jezza]

Hi Doddsy. For what it's worth i think what you are describing is dead algae. It is hard to tell from the pictures. If it puffs away when you brush it then that is a tell tale sign. Unless it's fine dust. Dirt and sand just tends to move around.
It only takes 1 occasion to drop below the appropriate FC level and you will be battling away until you eradicate it completely. The dead algae could be the result of when you raised the FC to mustard level but you need to start with a standard SLAM as I think it's probably green algae.

 

[Doddsy]

Hi Doddsy. For what it's worth i think what you are describing is dead algae. It is hard to tell from the pictures. If it puffs away when you brush it then that is a tell tale sign. Unless it's fine dust. Dirt and sand just tends to move around.
It only takes 1 occasion to drop below the appropriate FC level and you will be battling away until you eradicate it completely. The dead algae could be the result of when you raised the FC to mustard level but you need to start with a standard SLAM as I think it's probably green algae.

Alright, I’ll put through another SLAM just to make sure. I’m pretty sure I haven’t dropped below 3 since last one but I’ll do one just in case. Thanks.

 

[Lilypad]

Many of us keep our FC on the high end of the scale, as appropriate for our individual CYA levels. It is safe to swim in and gives you that extra wiggle room if you miss a chlorine addition. Keeps any problems at bay.

 

[Jezza]

Just make sure you keep at the SLAM going until there are no signs of any of the dead algae in the water. Hopefully you should find that it will clear up over time. Remember to keep running the filter 24/7. Always pays to keep recording your FC levels as you go along as it allows you to track how your going.

 

[Doddsy]

Just make sure you keep at the SLAM going until there are no signs of any of the dead algae in the water. Hopefully you should find that it will clear up over time. Remember to keep running the filter 24/7. Always pays to keep recording your FC levels as you go along as it allows you to track how your going.

Ok so not just until it passes a OCLT? Actually until there are no more signs of algae on the floor or poll.

 

[Jezza]

Yep the 3 criteria that you have passed the SLAM are

1.) Your pool is clear- no signs of algae dead or alive
2.) You pass the OCLT
3.) Your CC's are 0.5 or less

You must tick all 3 to declare you have it licked- otherwise there is a good chance it comes back again and you go through the cycle again