What kind of algae is this?

[DCFamily]

I opened our pool cover today and think we have black algae - but if anyone more familiar tells me I'm wrong, I'll be happy to hear it. These spots started on the steps but seem to be spreading. We would really appreciate advice on how to deal with this.

Here's the (very long) back story on how we got here:

We used a company to close the pool in the Fall and they reopened for the season a couple of weeks ago. We have yet to swim... A few days after pool opening, we opened the cover to an absolutely filthy pool. Dirt on the pool floor and dirty/hazy water. We called the company back and they vacuumed again and dumped in more shock. A few more days after that, we started troubleshooting further... Turns out the company didn't actually clean the DE filter in the Fall, didn't close the filter properly and actually didn't add ANY DE into the filter when they opened for the season. So, yes, shame on us for not discovering all of this sooner but here we are. My husband jumped into action mode immediately, cleaning the filter, adding DE. Our local pool store said get the filter situation sorted and then add 5 lbs of shock and then NoPhos (phosphates were really, really high) even though our CYA is basically 0. So we added the shock after sorting the filter and then adding NoPhos the next morning, then letting the filter run 48 hours. The water started becoming clear within hours of the filter actually working properly. When I went to test the water today to figure out next steps, I found these black/brown spots all over the pool and little fuzzy white balls floating around the pool. The fuzzy things I'm guessing are the NoPhos doing its job?

We have no idea what we should do. The pool store recommended shocking a lot because they weren't sure we're dealing with algae here. So we added 9 lbs of shock tonight after brushing the pool. (We've ordered stainless wire brushes since we don't have those.) Our pH was 7.2. The phosphates came down quite a lot but are still high (our home-test showed 500 whereas the in-store test showed 1043 with the same water being tested). Alkalinity was a touch high (4ppm over the range).

We have a salt chlorinator, keep the pool covered. We would appreciate advice on next steps. Do we get the CYA sorted before doing anything else? The phosphates? Keeping shocking and brushing? Adding algaecide?

Thank you in advance! Please be gentle as I'm already going to lose sleep over this.

 

[DCFamily]

I should add that we use(d) Leslie's Power Powder Plus Calcium Hypochlorite Pool Shock and that our pool is about 33,000 gallons.

 

[DCFamily]

I took a quick peek at the pool (it's pouring rain today) under the cover and there's noticeable improvement since shocking last night. Since we're new to maintaining our pool (I don't trust a pool company after this experience), I would really, really appreciate some input on next steps. Thank you!

 

[mknauss]

Welcome to forum!
You need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF-100/Pro or Taylor K2006C. A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

While you are waiting on your test kit, add 3 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - the Trouble Free Pool

 

[DCFamily]

Welcome to forum!
You need to follow the SLAM Process. To do that, you need a proper test kit. I suggest the TF-100/Pro or Taylor K2006C. A proper test kit is needed to get the accurate water chemistry results needed to follow the TFP protocols.

While you are waiting on your test kit, add 3 ppm FC worth of liquid chlorine / plain bleach to your pool each evening with the pump running. This will replenish the FC lost each day to the sun and also inhibit any algae in the water from growing further.
I suggest you read through Pool Care Basics - Trouble Free Pool and even look at a few of our videos TFP-TV - the Trouble Free Pool

Thank you very much! Just to make sure I'm doing everything in proper order:

- should we assume we're dealing with black algae and scrub the spots with a stainless steel brush every day before adding liquid chlorine? Or is normal brushing ok?
- while we wait for the test kit (I think we're going with the TF-100 Pro), we should only be adding liquid chlorine nightly?
- for the SLAM process checklist, am I correct that we first need to fix the CYA before proceeding to the next step in the list?
- the CYA is considered good to go, once the sock is in the water? Or do we wait longer? Not entirely clear on this.
- can we keep the daily cover on the pool as we're waiting to SLAM and during SLAM?

Hopefully we won't need to come back with more questions. Thank you again!

 

[mknauss]

Read Black Algae. Test to see if you have Black Algae.

Only chlorine. Until you have your kit, you do not know what else is needed.
You add the stabilizer to the sock and start dissolving it. At that point, you assume the CYA level is what you targeted and start the SLAM. Adjust the pH prior to raising the FC to SLAM level.
You need to leave the pool uncovered during the day when doing the SLAM.