Lay My Hat

Besides the CYA levels causing issues, often it's phosphates, these can be from all sorts of sources, people, hair products, washing detergent on costumes, birds etc. Keeping this level low removes the food for algae.
The finer the filtration, the more you remove from the water so less treatment required.
Just pointers towards easier management.

Thanks Teapot. I'll pass on the info.

teapot wrote: Your water must be nutrient rich in algae terms. Worth checking phosphate levels and whether the filtration is good enough, maybe add some seaKlear or jolly gel.

I think that might be our problem too Teapot, levels of chlorine, CYA, pH etc all good but we're still getting patches of algae on a weekly basis. Constantly having to sling a couple of litres of liquid chlorine in to clear it. Should we get sealer or jolly gel? Why would a pool become nutrient rich? Ours was emptied and refilled a month ago.

Give the algae patches a good brushing before treating the water as some algae type form a crust on their surface which can stop the chemicals reaching the parts you need to kill.

LotBoy47 wrote:Give the algae patches a good brushing before treating the water as some algae type form a crust on their surface which can stop the chemicals reaching the parts you need to kill.

Yep, gets brushed every time.

LotBoy47 wrote:Give the algae patches a good brushing before treating the water as some algae type form a crust on their surface which can stop the chemicals reaching the parts you need to kill.

Yep, gets brushed every time.

Groundhog Day? Must be the heat.

KathyG wrote:

teapot wrote: Your water must be nutrient rich in algae terms. Worth checking phosphate levels and whether the filtration is good enough, maybe add some seaKlear or jolly gel.

I think that might be our problem too Teapot, levels of chlorine, CYA, pH etc all good but we're still getting patches of algae on a weekly basis. Constantly having to sling a couple of litres of liquid chlorine in to clear it. Should we get sealer or jolly gel? Why would a pool become nutrient rich? Ours was emptied and refilled a month ago.

It shouldn't build up nutrient that quick, that said, phosphates are often added to water supplies to reduce corrosion so worth testing.
To keep things nice I and many others recommend maintaining the chlorine level at 5-7.5% of the CYA stabiliser level. This provides sufficient free chlorine to deal with most issues.

Its black algae that has the tough shell and its not actually an algae, its a cyanobacteria and very resistant, usually requires chlorine dioxide treatment. Just another example of the pool industry getting it wrong.