Patches of green algae

[dannytrigo]

Hi all,

I bought a house a year ago that has a salt water pool. It persistently gets green algae - mostly on the grout near the surface, all around the pool, even at the skimmer which has a lot of flow, but also patches at the bottom of the walls, corners, steps. It used to brush off quite easily but now I’m getting stubborn patches that won’t brush away.

I have my water tested regularly and it shows perfect chlorine levels, 4ppm. And stabiliser levels are good. The only thing out is the pH is a bit high at 8. The pool shop just suggested turning up my chlorinator but no other advice.

I run my pump around 3000 rpm for one hour, then 2500rpm for 7 hours and I’m based in South Florida so lots of sun. Pool is around 12,000 gallons from my very rough estimation.

This is my first time owning a pool, so is it normal to always have to brush algae away (like daily) or should the chlorine prevent any algae? And how do I tackle the stubborn patches?

Thanks in advance.

 

[Jimrahbe]

Danny,

The idea that 4 ppm of FC is good depends on the level of your CYA (Stablizer) which can't be 'good' it has to have a number.

The higher the CYA the higher the FC needs to be.

That said, once you get algae, normal FC levels will never be able to kill it. You need to perform what we call a SLAM to get rid of algae.
SLAM Process

To perform a SLAM you have to be able to test the pool water yourself, as you have to do it often.. This requires a 'real' test kit.

You should take a long read through our pool school and see what we are all about.

Thanks,

Jim R.

 

[Bperry]

Hi all,

I bought a house a year ago that has a salt water pool. It persistently gets green algae - mostly on the grout near the surface, all around the pool, even at the skimmer which has a lot of flow, but also patches at the bottom of the walls, corners, steps. It used to brush off quite easily but now I’m getting stubborn patches that won’t brush away.

I have my water tested regularly and it shows perfect chlorine levels, 4ppm. And stabiliser levels are good. The only thing out is the pH is a bit high at 8. The pool shop just suggested turning up my chlorinator but no other advice.

I run my pump around 3000 rpm for one hour, then 2500rpm for 7 hours and I’m based in South Florida so lots of sun. Pool is around 12,000 gallons from my very rough estimation.

This is my first time owning a pool, so is it normal to always have to brush algae away (like daily) or should the chlorine prevent any algae? And how do I tackle the stubborn patches?

Thanks in advance.

In addition to above advice, no it’s not normal to have algae growing in the pool. If there is, it means there’s not enough chlorine in it.

 

[dannytrigo]

Thanks for the replies. Here’s some more details on the chemical levels. I’m going to read up on the SLAM process.
The pool shop said i shouldn’t need to do a shock based on the levels.

Total chlorine, 4ppm
Free chlorine, 4ppm
Combined chlorine, 0ppm
pH, 8
Stabiliser, 60ppm
Salt, 3200ppm

 

[mknauss]

Welcome to the forum!
You will find TFPC is quite a bit different than pool store methods. We advocate the pool owner doing their own water testing with a proper test kit.
As Jim mentioned, you need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF-100 or Taylor K2006C. A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

Let us know when you get your test kit and post up the results.

 

[JJ_Tex]

Thanks for the replies. Here’s some more details on the chemical levels. I’m going to read up on the SLAM process.
The pool shop said i shouldn’t need to do a shock based on the levels.

Total chlorine, 4ppm
Free chlorine, 4ppm
Combined chlorine, 0ppm
pH, 8
Stabiliser, 60ppm
Salt, 3200ppm

While the chlorine numbers are in line for a Stabilizer(CYA) of 60, if you have algae you either dipped below the minimum chlorine levels or the pool store testing is bad (very likely, we do not trust their results).

Also the pool shop telling you you do not need more chlorine is just ignorant.
That would be akin to going to the doctor with a visible bacterial infection, but they don't give you antibiotics because your blood pressure looks fine.

 

[Bperry]

Thanks for the replies. Here’s some more details on the chemical levels. I’m going to read up on the SLAM process.
The pool shop said i shouldn’t need to do a shock based on the levels.

Total chlorine, 4ppm
Free chlorine, 4ppm
Combined chlorine, 0ppm
pH, 8
Stabiliser, 60ppm
Salt, 3200ppm

I wasn’t going to go down that road yet but most pool shop testing falls in the “you get what you pay for” type of accuracy, not very accurate.

 

[dannytrigo]

Ok, so I’ve ordered the testing kit and am preparing for what I’ll need to SLAM. I can get chlorinating liquid fairly cheap at Walmart which seems to just be 10% bleach. I’m comparing the website calculator and the app and am a little confused.

On the web, if I put 60 as my CYA, it says target 24 FC for SLAM. But in the app when I put 60 CYA and 24 as the target SLAM level it says it is out of the recommended range.

Does 24 sound roughly right? (I know I’ll have to test CYA properly when I get the kit).

That’s going to mean around 2.4 gallons of bleach according to the calculator (12k gal pool)

Just want to confirm these numbers don’t sound absolutely crazy.

I can’t use the pool while doing SLAM right?

 

[mknauss]

Does 24 sound roughly right? (I know I’ll have to test CYA properly when I get the kit).

Yes. The App says out of normal range. SLAM level FC is not normal. But necessary if you have algae.

I can’t use the pool while doing SLAM right?

You can. As long as you can see the bottom of the deep end for safety.

 

[dannytrigo]

You can. As long as you can see the bottom of the deep end for safety.

Thanks for the reply. Ah ok, I thought too much chlorine/bleach might be bad for skin/eyes. The water is perfectly clear, I just have some small algae patches on walls/steps/grout

 

[mknauss]

Ah ok, I thought too much chlorine/bleach might be bad for skin/eyes.

The SLAM level FC is designed to be no more harsh than 3 ppm FC without CYA. Which is most tap water and or public pools.
Low pH or CC is typically what effects skin and eyes.

 

[jsygrls]

I can get chlorinating liquid fairly cheap at Walmart which seems to just be 10% bleach

So, if Pinch A penny is your area , it's a go to place for chlorine in Florida. I use 2 of their 2.5 gallon jugs @10.5 % for about $16.00
( purchase 10 get one free also) and you don't have worries about expiration dates and handling multiple gallons. Also pick up the 2 jug caddie for travel protection.

 

[dannytrigo]

Pinch a penny is my current shop yea. Walmart seems to have 1 gallon of 10% sodium hypochlorite for $5-6 which seems roughly the same. I’ll probably just pick up the larger size there then

 

[JupiterFL]

I’m a Newbie, but I’ve noticed a lot of people seem to miss the fact that in a SLAM (especially in the beginning) you need to be testing and adjusting FC often. Best would be every 2 hours if you can. Instructions say twice a day minimum, but the more often the better.