Algae Splotches on Flagstone Sundeck?

[FlyersDude21]

We dont trust test results from anyone but the owner. Nobody cares about your pool more than you do.

Physically disrupt those spots then pour LC on them. The sooner the better. Thats pretty much it for now. After using the first two gallons of the LC, I would limit your adding to 1 gallon per day until you get your test kit.

Once you get your test kit, and you post a full set of results there is going to be a lot more information that we can provide.

There are some articles you should read posted. I am 98.75463% sure you will be advised to SLAM your pool, so read up on that. That will be based upon doing an OCLT, so read up on that.

This is all pretty easy, and the experts here have your back.

Thanks. Really appreciate the responses.
Not sure if you would know this but can we swim in the pool in 3 days if we add a gallon of LC a day and get this scrubbed 2 days in a row?

Until I get the test kit, I'll need to rely on the store tests. We're trying to swim later this week and over the weekend.

If you were in my shoes what would you do without a kit to get levels back to normal over the next few days. Pump a foot or 2 of water out and refill?

I'm wondering if I also need to do a SLAM, but again I don't think I can do that until I get my test kit which probably won't come until next week.

 

[PoolStored]

The algae is not a concern for swimming. Bacteria/pathogens are the concern.

It would be impossible to give you advice on swimming in the pool without knowing your CYA and FC levels. Take a read-->FC/CYA Levels

The basics: To have enough HOCl in the pool to kill bacteria/pathogens, we need to know the amount of CYA to tell you the FC level that would be safe from bacterial infections (forget algae).

We don't know your CYA and we don't know your FC.

You will need to make that decision regarding the health of you and your family. If you have been comfortable swimming NOT knowing the risk, like you know now, maybe you are comfortable with that. If it just you and your immediate family that lives in the house that is going to swim, the risk is pretty low. If you have extra-familial guests, the risk would be higher. If you have extra-familial guests with small children, the risks are even higher.

All the more reason to test your own water.

In either case, one piece advice is to never swim in the pool if you can't see the bottom.

 

[FlyersDude21]

The algae is not a concern for swimming. Bacteria/pathogens are the concern.

It would be impossible to give you advice on swimming in the pool without knowing your CYA and FC levels. Take a read-->FC/CYA Levels

The basics: To have enough HOCl in the pool to kill bacteria/pathogens, we need to know the amount of CYA to tell you the FC level that would be safe from bacterial infections (forget algae).

We don't know your CYA and we don't know your FC.

You will need to make that decision regarding the health of you and your family. If you have been comfortable swimming NOT knowing the risk, like you know now, maybe you are comfortable with that. If it just you and your immediate family that lives in the house that is going to swim, the risk is pretty low. If you have extra-familial guests, the risk would be higher. If you have extra-familial guests with small children, the risks are even higher.

All the more reason to test your own water.

In either case, one piece advice is to never swim in the pool if you can't see the bottom.

According to the chemical tests run at Store
FC - 0
Ph - 8
stabilizer / cya - 100

Temps are around 98-100 and full sun. The pool is clear as well.

 

[PoolStored]

stabilizer / cya - 100

Again, we don't trust pool store testing, it is notoriously wrong. Giving you advice based on that testing, we could do more harm.

I will say the following to help you decide:
With a CYA of 100 you need to maintain at least 3+ PPM of FC to kill bacteria/pathogens. See lowest blue line where it intercects with the Red horizontal line ( U.S. and WHO set as the minimum required for disinfection).


But, we don't know that your CYA is 100. CYA testing, particularly at higher levels is one area where the tests tend to be significantly off. As an example, here is the accuracy of Leslie's accublue. This assumes the machine is calibrated and operated properly.


25% error at CYA of 100. That could be 75 or 125...you just don't know. I've seen tests at 120 from the pool store and actual at 180.

Since the first chart is logarithmic for FC, you might need to maintain 6-10ppm at CYA of 125 to kill bacteria/pathogens...we just don't know. You are doing your own science at that point.

It is your pool, you get to decide. We can't, in good conscience, tell you it is safe. We don't know without proper testing. I wish we could do more, but at least you are informed on the risks..

 

[cwswifty]

As an example, here is the accuracy of Leslie's accublue. This assumes the machine is calibrated and operated properly.
View attachment 591806

25% error at CYA of 100. That could be 75 or 125...you just don't know.

Nice chart!

 

[PoolStored]

Nice chart!

Yeah, I stole it...Credit is yours!

 

[Katodude]

I am a little less cautious than most. If you swam in your pool last week, you can most likely swim in your pool this week. Your pool company has been using tabs to chlorinate your pool, so you have CYA in your pool, most likely a lot of it. Keep adding the LC to the pool and scrubbing those BA spots.

It’s a holiday week, enjoy your pool. You mentioned early that your water is clear, which is a strong indicator it is probably safe. Very few people get sick from their own pool. There is very little danger that you are putting too much chlorine in your pool. In fact the inverse is most likely true. You can most likely increase the chlorine amounts with much less risk.