Strange things growing in pool

[TamaraEnLaPlaya]

A friend has a pool that is lined with small mosaic tiles. Over the years the grout has become damaged, including several bouts of black algae, and some of the tiles have lifted off the walls and bottom. She knows it needs a complete revamp but is trying to keep it going for the time being. 
When I went to clean it for her today I found these strange strands appearing to grow in areas of the damaged grout. They brushed out really easily, along with some normal green algae that was coating the sides. 
The chemical balance of the water is spot on and the water was clean and bright before I started brushing. I've added some algaecide and left the sediment to settle overnight and hopefully can vac it all out tomorrow. The green algae is quite standard in hot Weather and of no real concern, but does anyone have any idea what these other things are and what if any treatment is needed?

the longest strand was about 3" long

[Archer]

Tamara, it looks to me like the roots from a nearby tree have found their way through the lining. It could be what has pushed off the mosaic tiles as well.
Difficult to resolve, as you need to find the source of the roots, and some trees here, like acacias, can travel many many metres and cause untold damage.

[Spitfire58]

They look viable shoots Tamara. Why not try & get them to grow & see what they are. Might give you some idea where they are coming from 🙂🙂

[TamaraEnLaPlaya]

Thanks Archer & Spitfire - good thoughts. I don't think it is stray tree roots as these shoots all seem to have their own little root tip (the white ends) but I'll try growing some. Strange that ordinary plants would grow in chlorine water though - that normally stunts or kills them. They appeared on all walls of the pool in the same week as well which doesn't seem likely with tree roots.

I didn't manage to get back there to vac today - it will have to wait until Tuesday when I'll do an update!


Any other thoughts/ideas from anyone very welcome please!

[Archer]

Tamara. What is your Free Chlorine level (ppm)? As you say you have green algae. Nothing should grow if you have it set high enough relative to the CYA level. Do you measure this?
FC is ineffective if CYA is too high.
If no-one is swimming this week whack it up to 35ppm.

[TamaraEnLaPlaya]

Hi Archer. Thanks for the info about CYA. Not something I've measured - I've just had a read up about it on Google.


I measure, using the little dipping strips:
Total Hardness (currently around 240)
Total Chlorine (2/2)
Free Chlorine (1/2)
pH (7.3)
Total Alkalinity (90)

Thanks to your post I remembered to check the expiry date on the dipping strips and they are well out of date! I'll buy some new ones and retest on Tuesday.

How do you measure CYA and where can you buy it, if needed?

[Archer]

Tamara. If you buy new test strips or a test kit, check it can measure CYA (Cyanuris Acid). This level is best kept below 100.

Most people have too much CYA, which makes the Chlorine ineffective.

If you have CYA below 100, then if you can increase the Chlorine level to 35-40ppm, and maintain it there for 3 days it will kill off everything, hopefully including your plantlife!

I find the best way to add Chlorine is in liquid form, then nothing else gets added and the water balance stays the same.

Good luck.

[Gone Fishing]

Hi Tamara

Is there a eucalyptus tree growing anywhere in your friend's garden ........ or next door?

They can travel many, many metres in their search for moisture and may have found almost unlimited supplies in the pool.

Eucalyptus roots are also more than capable of penetrating concrete and tile surrounds.

[TamaraEnLaPlaya]

I've ordered some new test strips that include the CYA test. 

No eucalyptus trees around! There is a yucca about 5M away in the garden and a couple of aloes. The ground (rock) drops away directly behind the pool/garden wall, about 10' drop, then a pavement and then there is a pepper tree in the 'verge'. Could it be seeds blowing in and settling in the gaps in the grout and taking root perhaps? Really will have to try growing some in a bucket of pool water as well as some in soil and see what develops!

Thanks again for everyone's help - keep the ideas coming please.

[Spitfire58]

Just looked at your photo again Tamara, I may be wrong but the white ends look to me like the growing tip & the black ends more like where they grew from the grout. Only my thoughts & an academic point really, unless you are trying to root them 🤣😂 They might end up in China 🤣😂🤣😂