Could this be algae or dirt/pollen?

[itstoohot]

I'm getting mixed feelings about this. We have had this show up in the pool. I shocked (with granular chlorine) and the chlorine level maintained somewhere between 5-10 the following day (using test strip). The pool company said I needed to brush the stuff off the floor to "meet" the chlorine, which I did. Still got the same chlorine reading the following morning.

The pictures posted are after we returned from a short vacation. The entire pool floor was covered. Assuming it was algae, I turned off the filter and triple shocked and brushed the entire pool floor. The following morning, I tested the chlorine and it was at least 10ppm (test strip doesn't go any higher). Now I'm back to thinking it's only dirt/pollen, so I started the filter and poured in clarifier. That was 2 days ago. The water is now dirty and cloudy and I can't see the deep end drain.

Specifics, if you need them (chemicals based on closest color test strip):
30,000 gal in ground vinyl liner
PH - 7.8
Alkalinity - 120
Total & Free Chlorine - 10 or above
Cyanuric Acid/Conditioner - between 50 and 100

Thanks so much for your help,
David

[Pamsel]

There are other folks here with lots more experience than I, who can be of better help but one thing you really need to do is get more accurate test result numbers. CYA from 50-100 is too wide a range to know what your proper Chlorine level should be. Also, you need to know your CL level ~ how much above 10ppm? Everyone here recommends using a better testing method than test strips. If you don't have a good kit, you can take a water sample to a reliable pool supply store and have the water tested for you.

One thing you can do is feel the stuff settling in your pool and see if it's gritty or slimy. That will help you to determine if it's dirt or algae. I'm sure someone else will chime in with some good advice for you.

[itstoohot]

I'm working on getting to the pool store today for a current reading (and will purchase a test kit). As for the feel - it's not gritty.

[waterbear]

It is hard to tell from the picture but it looks like it could be mustard algae. You need an accurate set of test results so we can help you with it if it is mustard algae. Especially an accurate CYA reading since that will determine just how high you need to go with your shock levels to kill it.

[ShelleyAnn]

DO NOT trust the pool store to give you accurate readings ESPECIALLY CYA

[ChuckD]

Also, keep your filter running; you mentioned you turned it off.

C.

[waterbear]

DO NOT trust the pool store to give you accurate readings ESPECIALLY CYA

This really depends on the store and who is doing the testing. Let's be fair now. I am the first one to say that many pool store employees who test water are clueless but there ARE a few of us good ones out there!

[itstoohot]

OK, back from the pool store. Here we go:

PH - 7.8
FC - 6+
TC - 6+
TA - 140
CYA - 80
Copper - .06

Pool temp is about 78F

I sampled the stuff and pool store says its algae. They are also a little confused that I still get chlorine readings with this stuff in the pool. They had me purchase Green Treat by United Chemical. I haven't put it in yet. It is sodium bromide based (48.5%).

Thanks for all your help!

[CarlD]

DON'T USE THAT STUFF!!!!! YOU'll SPEND WEEKS ADDING TONS OF CHLORINE TO GET IT OUT!!!!!!! THE CURE IS WORSE BY FAR THAN THE DISEASE!!!!

It's only for desperation situations--which you do NOT have!

Nowhere have I seen that you VACUUMED your pool. Do so and see if it goes away and returns. I get all kinds of similar looking stuff on the bottom of my pool from pollen and dust and it just vacuums up and the pool chemistry is FINE. It looks a lot like that but it's definitely NOT algae--it is brown but not a problem.

[itstoohot]

I have tried to vaccuum and found it returning through the jets. I pulled the filters out to clean them, assuming they were at capacity, and found them to be rather clean except for a yellowish-greenish hue to the water running out of the cartridges. I have not tried vaccuuming since I put in the clean cartridges.